P 532 APPENDIX TO THE TRANSCENDENTAL DIALECTIC THE REGULATIVE EMPLOYMENT OF THE IDEAS OF PURE REASON The outcome of all dialectical attempts of pure reason does not merely confirm what we have already proved in the Transcendental Analytic, namely, that all those conclusions of ours which profess to lead us beyond the field of possible experience are deceptive and without foundation; it likewise teaches us this further lesson, that human reason has a natural tendency to transgress these limits, and that transcendental ideas are just as natural to it as the categories are to understanding -- though with this difference, that while the categories lead to truth, that is, to the conformity of our concepts with the object, the ideas produce what, though a mere illusion, is none the less irresistible, and the harmful influence of which we can barely succeed in neutralising even by means of the severest criticism. Everything that has its basis in the nature of our powers must be appropriate to, and consistent with, their right employment -- if only we can guard against a certain misunderstanding and so can discover the proper direction of these powers. We are entitled, therefore, to suppose that transcendental ideas have their own good, proper, and therefore immanent use, although, when their meaning is misunderstood, and they are taken for concepts of real things, they become transcendent in their application and for that very reason can be delusive. For it is not the idea in itself, but its use only, that can be either transcendent or immanent (that is, either range beyond all possible experience or find employment within its limits), according as it is applied to an object which is supposed to correspond to it, or is directed solely to the use of understanding in general, in respect of those objects that fall to be dealt with by the understanding. All errors of subreption are to be ascribed to a defect of judgment, never to understanding or to reason. Reason is never in immediate relation to an object, but P 533 only to the understanding; and it is only through the understanding that it has its own [specific] empirical employment. It does not, therefore, create concepts (of objects) but only orders them, and gives them that unity which they can have only if they be employed in their widest possible application, that is, with a view to obtaining totality in the various series. The understanding does not concern itself with this totality, but only with that connection through which, in accordance with concepts, such series of conditions come into being. Reason has, therefore, as its sole object, the understanding and its effective application. Just as the understanding unifies the manifold in the object by means of concepts, so reason unifies the manifold of concepts by means of ideas, positing a certain collective unity as the goal of the activities of the understanding, which otherwise are concerned solely with distributive unity. I accordingly maintain that transcendental ideas never allow of any constitutive employment. When regarded in that mistaken manner, and therefore as supplying concepts of certain objects, they are but pseudo-rational, merely dialectical concepts. On the other hand, they have an excellent, and indeed indispensably necessary, regulative employment, namely, that of directing the understanding towards a certain goal upon which the routes marked out by all its rules converge, as upon their point of intersection. This point is indeed a mere idea, a focus imaginarius, from which, since it lies quite outside the bounds of possible experience, the concepts of the understanding do not in reality proceed; none the less it serves to give to these concepts the greatest [possible] unity combined with the greatest [possible] extension. Hence arises the illusion that the lines have their source in a real object lying outside the field of empirically possible knowledge -- just as objects reflected in a mirror are seen as behind it. Nevertheless this illusion (which need not, however, be allowed to deceive us) is indispensably necessary if we are to direct the understanding beyond every given experience (as part of the sum of possible experience), and thereby to secure its greatest possible extension, just as, in the case of mirror- vision, the illusion involved is indispensably necessary if, P 534 besides the objects which lie before our eyes, we are also to see those which lie at a distance behind our back. If we consider in its whole range the knowledge obtained for us by the understanding, we find that what is peculiarly distinctive of reason in its attitude to this body of knowledge, is that it prescribes and seeks to achieve its systematisation, that is, to exhibit the connection of its parts in conformity with a single principle. This unity of reason always presupposes an idea, namely, that of the form of a whole of knowledge -- a whole which is prior to the determinate knowledge of the parts and which contains the conditions that determine a priori for every part its position and relation to the other parts. This idea accordingly postulates a complete unity in the knowledge obtained by the understanding, by which this knowledge is to be not a mere contingent aggregate, but a system connected according to necessary laws. We may not say that this idea is a concept of the object, but only of the thoroughgoing unity of such concepts, in so far as that unity serves as a rule for the understanding. These concepts of reason are not derived from nature; on the contrary, we interrogate nature in accordance with these ideas, and consider our knowledge as defective so long as it is not adequate to them. By general admission, pure earth, pure water, pure air, etc. , are not to be found. We require, however, the concepts of them (though, in so far as their complete purity is concerned, they have their origin solely in reason) in order properly to determine the share which each of these natural causes has in producing appearances. Thus in order to explain the chemical interactions of bodies in accordance with the idea of a mechanism, every kind of matter is reduced to earths (qua mere weight), to salts and inflammable substances (qua force), and to water and air as vehicles (machines, as it were, by which the first two produce their effects). The modes of expression usually employed are, indeed, somewhat different; but the influence of reason on the classifications of the natural scientist is still easily detected. If reason is a faculty of deducing the particular from the universal, and if the universal is already certain in itself and given, only judgment is required to execute the process of P 535 subsumption, and the particular is thereby determined in a necessary manner. This I shall entitle the apodeictic use of reason. If, however, the universal is admitted as problematic only, and is a mere idea, the particular is certain, but the universality of the rule of which it is a consequence is still a problem. Several particular instances, which are one and all certain, are scrutinised in view of the rule, to see whether they follow from it. If it then appears that all particular instances which can be cited follow from the rule, we argue to its universality, and from this again to all particular instances, even to those which are not themselves given. This I shall entitle the hypothetical employment of reason. The hypothetical employment of reason, based upon ideas viewed as problematic concepts, is not, properly speaking, constitutive, that is, it is not of such a character that, judging in all strictness, we can regard it as proving the truth of the universal rule which we have adopted as hypothesis. For how are we to know all the possible consequences which, as actually following from the adopted principle, prove its universality? The hypothetical employment of reason is regulative only; its sole aim is, so far as may be possible, to bring unity into the body of our detailed knowledge, and thereby to approximate the rule to universality. The hypothetical employment of reason has, therefore, as its aim the systematic unity of the knowledge of understanding, and this unity is the criterion of the truth of its rules. The systematic unity (as a mere idea) is, however, only a projected unity, to be regarded not as given in itself, but as a problem only. This unity aids us in discovering a principle for the understanding in its manifold and special modes of employment, directing its attention to cases which are not given, and thus rendering it more coherent. But the only conclusion which we are justified in drawing from these considerations is that the systematic unity of the manifold knowledge of understanding, as prescribed by reason, is a logical principle. Its function is to assist the understanding by means of ideas, in those cases in which the understanding cannot by itself establish rules, and at the same time to give P 536 to the numerous and diverse rules of the understanding unity or system under a single principle, and thus to secure coherence in every possible way. But to say that the constitution of the objects or the nature of the understanding which knows them as such, is in itself determined to systematic unity, and that we can in a certain measure postulate this unity a priori, without reference to any such special interest of reason, and that we are therefore in a position to maintain that knowledge of the understanding in all its possible modes (including empirical knowledge) has the unity required by reason, and stands under common principles from which all its various modes can, in spite of their diversity, be deduced -- that would be to assert a transcendental principle of reason, and would make the systematic unity necessary, not only subjectively and logically, as method, but objectively also. We may illustrate this by an instance of the employment of reason. Among the various kinds of unity which conform to the concepts of the understanding, is that of the causality of a substance, which is called power. The various appearances of one and the same substance show at first sight so great a diversity, that at the start we have to assume just as many different powers as there are different effects. For instance in the human mind we have sensation, consciousness, imagination, memory, wit, power of discrimination, pleasure, desire, etc. Now there is a logical maxim which requires that we should reduce, so far as may be possible, this seeming diversity, by comparing these with one another and detecting their hidden identity. We have to enquire whether imagination combined with consciousness may not be the same thing as memory, wit, power of discrimination, and perhaps even identical with understanding and reason. Though logic is not capable of deciding whether a fundamental power actually exists, the idea of such a power is the problem involved in a systematic representation of the multiplicity of powers. The logical principle of reason calls upon us to bring about such unity as completely as possible; and the more the appearances of this and that power are found to be identical with one another, the more probable it becomes that they are simply different manifestations of one and the same power, P 537 which may be entitled, relatively to the more specific powers, the fundamental power. The same is done with the other powers. The relatively fundamental powers must in turn be compared with one another, with a view to discovering their harmony, and so to bring them nearer to a single radical, that is, absolutely fundamental, power. But this unity of reason is purely hypothetical. We do not assert that such a power must necessarily be met with, but that we must seek it in the interests of reason, that is, of establishing certain principles for the manifold rules which experience may supply to us. We must endeavour, wherever possible, to bring in this way systematic unity into our knowledge. On passing, however, to the transcendental employment of understanding, we find that this idea of a fundamental power is not treated merely as a problem for the hypothetical use of reason, but claims to have objective reality, as postulating the systematic unity of the various powers of a substance, and as giving expression to an apodeictic principle of reason. For without having made any attempt to show the harmony of these various powers, nay, even after all attempts to do so have failed, we yet presuppose that such a unity does actually exist, and this not only, as in the case cited, on account of the unity of the substance, but also in those cases in which, as with matter in general, we encounter powers which, though to a certain extent homogeneous, are likewise diverse. In all such cases reason presupposes the systematic unity of the various powers, on the ground that special natural laws fall under more general laws, and that parsimony in principles is not only an economical requirement of reason, but is one of nature's own laws. It is, indeed, difficult to understand how there can be a logical principle by which reason prescribes the unity of rules, unless we also presuppose a transcendental principle whereby such a systematic unity is a priori assumed to be necessarily inherent in the objects. For with what right can reason, in its logical employment, call upon us to treat the multiplicity of powers exhibited in nature as simply a disguised unity and to derive this unity, so far as may be possible, from a fundamental power -- how can reason do this, if it be free to admit P 538 as likewise possible that all powers may be heterogeneous, and that such systematic unity of derivation may not be in conformity with nature? Reason would then run counter to its own vocation, proposing as its aim an idea quite inconsistent with the constitution of nature. Nor can we say that reason, while proceeding in accordance with its own principles, has arrived at knowledge of this unity through observation of the accidental constitution of nature. The law of reason which requires us to seek for this unity, is a necessary law, since without it we should have no reason at all, and without reason no coherent employment of the understanding, and in the absence of this no sufficient criterion of empirical truth. In order, therefore, to secure an empirical criterion we have no option save to presuppose the systematic unity of nature as objectively valid and necessary. Although philosophers have not always acknowledged this transcendental principle, even to themselves, or indeed been conscious of employing it, we none the less find it covertly implied, in remarkable fashion, in the principles upon which they proceed. That the manifold respects in which individual things differ do not exclude identity of species, that the various species must be regarded merely as different determinations of a few genera, and these, in turn, of still higher genera, and so on; in short, that we must seek for a certain systematic unity of all possible empirical concepts, in so far as they can be deduced from higher and more general concepts -- this is a logical principle, a rule of the Schools, without which there could be no employment of reason. For we can conclude from the universal to the particular, only in so far as universal properties are ascribed to things as being the foundation upon which the particular properties rest. That such unity is to be found in nature, is presupposed by philosophers in the well-known scholastic maxim, that rudiments or principles must not be unnecessarily multiplied (entia praeter necessitatem non esse multiplicanda). This maxim declares that things by their very nature supply material for the unity of reason, and that the seemingly infinite variety need not hinder us from assuming that behind this variety there is a unity of fundamental properties -- properties from which the P 539 diversity can be derived through repeated determination. This unity, although it is a mere idea, has been at all times so eagerly sought, that there has been need to moderate the desire for it, not to encourage it. A great advance was made when chemists succeeded in reducing all salts to two main genera, acids and alkalies; and they endeavour to show that even this difference is merely a variety, or diverse manifestation, of one and the same fundamental material. Chemists have sought, step by step, to reduce the different kinds of earths (the material of stones and even of metals) to three, and at last to two; but, not content with this, they are unable to banish the thought that behind these varieties there is but one genus, nay, that there may even be a common principle for the earths and the salts. It might be supposed that this is merely an economical contrivance whereby reason seeks to save itself all possible trouble, a hypothetical attempt, which, if it succeeds, will, through the unity thus attained, impart probability to the presumed principle of explanation. But such a selfish purpose can very easily be distinguished from the idea. For in conformity with the idea everyone presupposes that this unity of reason accords with nature itself, and that reason -- although indeed unable to determine the limits of this unity -- does not here beg but command. If among the appearances which present themselves to us, there were so great a variety -- I do not say in form, for in that respect the appearances might resemble one another; but in content, that is, in the manifoldness of the existing entities -- that even the acutest human understanding could never by comparison of them detect the slightest similarity (a possibility which is quite conceivable), the logical law of genera would have no sort of standing; we should not even have the concept of a genus, or indeed any other universal concept; and the understanding itself, which has to do solely with such concepts, would be non-existent. If, therefore, the logical principle of genera is to be applied to nature (by which I here understand those objects only which are given to us), it presupposes a transcendental principle. And in accordance with this latter principle, homogeneity is necessarily presupposed in the manifold of possible experience (although we are not in a position to determine in a priori fashion its degree); for in the absence P 540 of homogeneity, no empirical concepts, and therefore no experience, would be possible. The logical principle of genera, which postulates identity, is balanced by another principle, namely, that of species, which calls for manifoldness and diversity in things, notwithstanding their agreement as coming under the same genus, and which prescribes to the understanding that it attend to the diversity no less than to the identity. This principle (of discriminative observation, that is, of the faculty of distinction) sets a limit to possible indiscretion in the former principle (of the faculty of wit); and reason thus exhibits a twofold, self-conflicting interest, on the one hand interest in extent (universality) in respect of genera, and on the other hand in content (determinateness) in respect of the multiplicity of the species. In the one case the understanding thinks more under its concepts, in the other more in them. This twofold interest manifests itself also among students of nature in the diversity of their ways of thinking. Those who are more especially speculative are, we may almost say, hostile to heterogeneity, and are always on the watch for the unity of the genus; those, on the other hand, who are more especially empirical, are constantly endeavouring to differentiate nature in such manifold fashion as almost to extinguish the hope of ever being able to determine its appearances in accordance with universal principles. This latter mode of thought is evidently based upon a logical principle which aims at the systematic completeness of all knowledge -- prescribing that, in beginning with the genus, we descend to the manifold which may be contained thereunder, in such fashion as to secure extension for the system, just as in the alternative procedure, that of ascending to the genus, we endeavour to secure the unity of the system. For if we limit our attention to the sphere of the concept which marks out a genus, we can no more determine how far it is possible to proceed in the [logical] division of it, than we can judge merely from the space which a body occupies how far it is possible to proceed in the [physical] division of its parts. Consequently, P 541 every genus requires diversity of species, and these in turn diversity of subspecies; and since no one of these subspecies is ever itself without a sphere (extent as conceptus communis), reason, in being carried to completion, demands that no species be regarded as being in itself the lowest. For since the species is always a concept, containing only what is common to different things, it is not completely determined. It cannot, therefore, be directly related to an individual, and other concepts, that is, subspecies, must always be contained under it. This law of specification can be formulated as being the principle: entium varietates non temere esse minuendas. But it is easily seen that this logical law would be without meaning and application if it did not rest upon a transcendental law of specification, which does not indeed demand an actual infinity of differences in the things which can be objects to us -- the logical principle, as affirming only the indeterminateness of the logical sphere in respect of possible division, gives no occasion for any such assertion -- but which none the less imposes upon the understanding the obligation of seeking under every discoverable species for subspecies, and under every difference for yet smaller differences. For if there were no lower concepts, there could not be higher concepts. Now the understanding can have knowledge only through concepts, and therefore, however far it carries the process of division, never through mere intuition, but always again through lower concepts. The knowledge of appearances in their complete determination, which is possible only through the understanding, demands an endless progress in the specification of our concepts, and an advance to yet other remaining differences, from which we have made abstraction in the concept of the species, and still more so in that of the genus. This law of specification cannot be derived from experience, which can never open to our view any such extensive prospects. Empirical specification soon comes to a stop in the distinction of the manifold, if it be not guided by the antecedent transcendental law of specification, which, as a principle of reason, leads us to seek always for further differences, and to suspect their existence even when the senses are unable to disclose them. That absorbent earths are of different kinds (chalk and muriatic earths), is a discovery that was possible P 542 only under the guidance of an antecedent rule of reason -- reason proceeding on the assumption that nature is so richly diversified that we may presume the presence of such differences, and therefore prescribing to the understanding the task of searching for them. Indeed it is only on the assumption of differences in nature, just as it is also only under the condition that its objects exhibit homogeneity, that we can have any faculty of understanding whatsoever. For the diversity of that which is comprehended under a concept is precisely what gives occasion for the employment of the concept and the exercise of the understanding. Reason thus prepares the field for the understanding: (1) through a principle of the homogeneity of the manifold under higher genera; (2) through a principle of the variety of the homogeneous under lower species; and (3) in order to complete the systematic unity, a further law, that of the affinity of all concepts -- a law which prescribes that we proceed from each species to every other by gradual increase of the diversity. These we may entitle the principles of homogeneity, specification, and continuity of forms. The last named arises from union of the other two, inasmuch as only through the processes of ascending to the higher genera and of descending to the lower species do we obtain the idea of systematic connection in its completeness. For all the manifold differences are then related to one another, inasmuch as they one and all spring from one highest genus, through all degrees of a more and more widely extended determination. The systematic unity, prescribed by the three logical principles, can be illustrated in the following manner. Every concept may be regarded as a point which, as the station for an observer, has its own horizon, that is, a variety of things which can be represented, and, as it were, surveyed from that standpoint. This horizon must be capable of containing an infinite number of points, each of which has its own narrower horizon; that is, every species contains subspecies, according to the principle of specification, and the logical horizon consists exclusively of smaller horizons (subspecies), never of points which possess no extent (individuals). But for different horizons, that is, genera, each of which is determined by its own concept, there can be a common horizon, in reference to P 543 which, as from a common centre, they can all be surveyed; and from this higher genus we can proceed until we arrive at the highest of all genera, and so at the universal and true horizon, which is determined from the standpoint of the highest concept, and which comprehends under itself all manifoldness -- genera, species, and subspecies. We are carried to this highest standpoint by the law of homogeneity, and to all lower standpoints, and their greatest possible variety, by the law of specification. And since there is thus no void in the whole sphere of all possible concepts, and since nothing can be met with outside this sphere, there arises from the presupposition of this universal horizon and of its complete division, the principle: non datur vacuum formarum, that is, that there are not different, original, first genera, which are isolated from one another, separated, as it were, by an empty intervening space; but that all the manifold genera are simply divisions of one single highest and universal genus. From this principle there follows, as its immediate consequence: datur continuum formarum, that is, that all differences of species border upon one another, admitting of no transition from one to another per saltum, but only through all the smaller degrees of difference that mediate between them. In short, there are no species or subspecies which (in the view of reason) are the nearest possible to each other; still other intermediate species are always possible, the difference of which from each of the former is always smaller than the difference between these. The first law thus keeps us from resting satisfied with an excessive number of different original genera, and bids us pay due regard to homogeneity; the second, in turn, imposes a check upon this tendency towards unity, and insists that before we proceed to apply a universal concept to individuals we distinguish subspecies within it. The third law combines these two laws by prescribing that even amidst the utmost manifoldness we observe homogeneity in the gradual transition from one species to another, and thus recognise a relationship of the different branches, as all springing from the same stem. This logical law of the continuum specierum (formarum logicarum) presupposes, however, a transcendental law (lex P 544 continui in natura), without which the former law would only lead the understanding astray, causing it to follow a path which is perhaps quite contrary to that prescribed by nature itself. This law must therefore rest upon pure transcendental, not on empirical, grounds. For if it rested on empirical grounds, it would come later than the systems, whereas in actual fact it has itself given rise to all that is systematic in our knowledge of nature. The formulation of these laws is not due to any secret design of making an experiment, by putting them forward as merely tentative suggestions. Such anticipations, when confirmed, yield strong evidence in support of the view that the hypothetically conceived unity is well-grounded; and such evidence has therefore in this respect a certain utility. But it is evident that the laws contemplate the parsimony of fundamental causes, the manifoldness of effects, and the consequent affinity of the parts of nature as being in themselves in accordance both with reason and with nature. Hence these principles carry their recommendation directly in themselves, and not merely as methodological devices. But it is easily seen that this continuity of forms is a mere idea, to which no congruent object can be discovered in experience. For in the first place, the species in nature are actually divided, and must therefore constitute a quantum discretum. Were the advance in the tracing of their affinity continuous, there would be a true infinity of intermediate members between any two given species, which is impossible. And further, in the second place, we could not make any determinate empirical use of this law, since it instructs us only in quite general terms that we are to seek for grades of affinity, and yields no criterion whatsoever as to how far, and in what manner, we are to prosecute the search for them. If we place these principles of systematic unity in the order appropriate to their empirical employment, they will stand thus: manifoldness, affinity, unity, each being taken, as an idea, in the highest degree of its completeness. Reason presupposes the knowledge which is obtained by the understanding and which stands in immediate relation to experience, and P 545 seeks for the unity of this knowledge in accordance with ideas which go far beyond all possible experience. The affinity of the manifold (as, notwithstanding its diversity, coming under a principle of unity) refers indeed to things, but still more to their properties and powers. Thus, for instance, if at first our imperfect experience leads us to regard the orbits of the planets as circular, and if we subsequently detect deviations therefrom, we trace the deviations to that which can change the circle, in accordance with a fixed law, through all the infinite intermediate degrees, into one of these divergent orbits. That is to say, we assume that the movements of the planets which are not circular will more or less approximate to the properties of a circle; and thus we come upon the idea of an ellipse. Since the comets do not, so far as observation reaches, return in any such courses, their paths exhibit still greater deviations. What we then do is to suppose that they proceed in a parabolic course, which is akin to the ellipse, and which in all our observation is indistinguishable from an ellipse that has its major axis indefinitely extended. Thus, under the guidance of these principles, we discover a unity in the generic forms of the orbits, and thereby a unity in the cause of all the laws of planetary motion, namely, gravitation. And we then extend our conquests still further, endeavouring to explain by the same principle all variations and seeming departures from these rules; finally, we even go on to make additions such as experience can never confirm, namely, to conceive, in accordance with the rules of affinity, hyperbolic paths of comets, in the course of which these bodies entirely leave our solar system, and passing from sun to sun, unite the most distant parts of the universe -- a universe which, though for us unlimited, is throughout held together by one and the same moving force. The remarkable feature of these principles, and what in them alone concerns us, is that they seem to be transcendental, and that although they contain mere ideas for the guidance of the empirical employment of reason -- ideas which reason follows only as it were asymptotically, i.e. ever more closely without ever reaching them -- they yet possess, as synthetic a priori propositions, objective but indeterminate validity, and serve as rules for possible experience. They can also be employed with great advantage in the elaboration of experience, P 546 as heuristic principles. A transcendental deduction of them cannot, however, be effected; in the case of ideas, as we have shown above, such a deduction is never possible. In the Transcendental Analytic we have distinguished the dynamical principles of the understanding, as merely regulative principles of intuition, from the mathematical, which, as regards intuition, are constitutive. None the less these dynamical laws are constitutive in respect of experience, since they render the concepts, without which there can be no experience, possible a priori. But principles of pure reason can never be constitutive in respect of empirical concepts; for since no schema of sensibility corresponding to them can ever be given, they can never have an object in concreto. If, then, we disallow such empirical employment of them, as constitutive principles, how are we to secure for them a regulative employment, and therewith some sort of objective validity, and what can we mean by such regulative employment? The understanding is an object for reason, just as sensibility is for the understanding. It is the business of reason to render the unity of all possible empirical acts of the understanding systematic; just as it is of the understanding to connect the manifold of the appearances by means of concepts, and to bring it under empirical laws. But the acts of the understanding are, without the schemata of sensibility, undetermined; just as the unity of reason is in itself undetermined, as regards the conditions under which, and the extent to which, the understanding ought to combine its concepts in systematic fashion. But although we are unable to find in intuition a schema for the complete systematic unity of all concepts of the understanding, an analogon of such a schema must necessarily allow of being given. This analogon is the idea of the maximum in the division and unification of the knowledge of the understanding under one principle. For what is greatest and absolutely complete can be determinately thought, all restricting conditions, which give rise to an indeterminate manifoldness, being left aside. Thus the idea of reason is an analogon of a schema of sensibility; but with this difference, that the application of the concepts of the understanding to the schema of reason does not yield knowledge of the object itself (as is the case in the application of categories to their P 547 sensible schemata) but only a rule or principle for the systematic unity of all employment of the understanding. Now since every principle which prescribes a priori to the understanding thoroughgoing unity in its employment, also holds, although only indirectly, of the object of experience, the principles of pure reason must also have objective reality in respect of that object, not, however, in order to determine anything in it, but only in order to indicate the procedure whereby the empirical and determinate employment of the understanding can be brought into complete harmony with itself. This is acheived by bringing its employment, so far as may be possible, into connection with the principle of thoroughgoing unity, and by determining its procedure in the light of this principle. I entitle all subjective principles which are derived, not from the constitution of an object but from the interest of reason in respect of a certain possible perfection of the knowledge of the object, maxims of reason. There are therefore maxims of speculative reason, which rest entirely on its speculative interest, although they may seem to be objective principles. When merely regulative principles are treated as constitutive, and are therefore employed as objective principles, they may come into conflict with one another. But when they are treated merely as maxims, there is no real conflict, but merely those differences in the interest of reason that give rise to differing modes of thought. In actual fact, reason has only one single interest, and the conflict of its maxims is only a difference in, and a mutual limitation of, the methods whereby this interest endeavours to obtain satisfaction. Thus one thinker may be more particularly interested in manifoldness (in accordance with the principle of specification), another thinker in unity (in accordance with the principle of aggregation). Each believes that his judgment has been arrived at through insight into the object, whereas it really rests entirely on the greater or lesser attachment to one of the two principles. And since neither of these principles is based on objective grounds, but solely on the interest of reason, the P 548 title 'principles' is not strictly applicable; they may more fittingly be entitled 'maxims'. When we observe intelligent people disputing in regard to the characteristic properties of men, animals, or plants -- even of bodies in the mineral realm -- some assuming, for instance, that there are certain special hereditary characteristics in each nation, certain well-defined inherited differences in families, races, etc. , whereas others are bent upon maintaining that in all such cases nature has made precisely the same provision for all, and that it is solely to external accidental conditions that the differences are due, we have only to consider what sort of an object it is about which they are making these assertions, to realise that it lies too deeply hidden to allow of their speaking from insight into its nature. The dispute is due simply to the twofold interest of reason, the one party setting its heart upon, or at least adopting, the one interest, and the other party the other. The differences between the maxims of manifoldness and of unity in nature thus easily allow of reconciliation. So long, however, as the maxims are taken as yielding objective insight, and until a way has been discovered of adjusting their conflicting claims, and of satisfying reason in that regard, they will not only give rise to disputes but will be a positive hindrance, and cause long delays in the discovery of truth. Similar observations are relevant in regard to the assertion or denial of the widely discussed law of the continuous gradation of created beings, which was propounded by Leibniz, and admirably supported by Bonnet. It is simply the following out of that principle of affinity which rests on the interest of reason. For observation and insight into the constitution of nature could never justify us in the objective assertion of the law. The steps of this ladder, as they are presented to us in experience, stand much too far apart; and what may seem to us small differences are usually in nature itself such wide gaps, that from any such observations we can come to no decision in regard to nature's ultimate design -- especially if we bear in mind that in so great a multiplicity of things there can never be much difficulty in finding similarities and approximations. On the other hand, the method of looking for order in nature P 549 in accordance with such a principle, and the maxim which prescribes that we regard such order -- leaving, however, undetermined where and how far -- as grounded in nature as such, is certainly a legitimate and excellent regulative principle of reason. In this regulative capacity it goes far beyond what experience or observation can verify; and though not itself determining anything, yet serves to mark out the path towards systematic unity. THE FINAL PURPOSE OF THE NATURAL DIALECTIC OF HUMAN REASON The ideas of pure reason can never be dialectical in themselves; any deceptive illusion to which they give occasion must be due solely to their misemployment. For they arise from the very nature of our reason; and it is impossible that this highest tribunal of all the rights and claims of speculation should itself be the source of deceptions and illusions. Presumably, therefore, the ideas have their own good and appropriate vocation as determined by the natural disposition of our reason. The mob of sophists, however, raise against reason the usual cry of absurdities and contradictions, and though unable to penetrate to its innermost designs, they none the less inveigh against its prescriptions. Yet it is to the beneficent influences exercised by reason that they owe the possibility of their own self-assertiveness, and indeed that very culture which enables them to blame and to condemn what reason requires of them. We cannot employ an a priori concept with any certainty without having first given a transcendental deduction of it. The ideas of pure reason do not, indeed, admit of the kind of deduction that is possible in the case of the categories. But if they are to have the least objective validity, no matter how indeterminate that validity may be, and are not to be mere empty thought-entities (entia rationis ratiocinantis), a deduction of them must be possible, however greatly (as we admit) it may differ from that which we have been able to give of the categories. This will complete the critical work of pure reason, and is what we now propose to undertake. P 550 There is a great difference between something being given to my reason as an object absolutely, or merely as an object in the idea. In the former case our concepts are employed to determine the object; in the latter case there is in fact only a schema which no object, not even a hypothetical one, is directly given, and which only enables us to represent to ourselves other objects in an indirect manner, namely in their systematic unity, by means of their relation to this idea. Thus I say that the concept of a highest intelligence is a mere idea, that is to say, its objective reality is not to be taken as consisting in its referring directly to an object (for in that sense we should not be able to justify its objective validity). It is only a schema constructed in accordance with the conditions of the greatest possible unity of reason -- the schema of the concept of a thing in general, which serves only to secure the greatest possible systematic unity in the empirical employment of our reason. We then, as it were, derive the object of experience from the supposed object of this idea, viewed as the ground or cause of the object of experience. We declare, for instance, that the things of the world must be viewed as if they received their existence from a highest intelligence. The idea is thus really only a heuristic, not an ostensive concept. It does not show us how an object is constituted, but how, under its guidance, we should seek to determine the constitution and connection of the objects of experience. If, then, it can be shown that the three transcendental ideas (the psychological, the cosmological, and the theological), although they do not directly relate to, or determine, any object corresponding to them, none the less, as rules of the empirical employment of reason, lead us to systematic unity, under the presupposition of such an object in the idea; and that they thus contribute to the extension of empirical knowledge, without ever being in a position to run counter to it, we may conclude that it is a necessary maxim of reason to proceed always in accordance with such ideas. This, indeed, is the transcendental deduction of all ideas of speculative reason, not as constitutive principles for the extension of our knowledge to more objects than experience can give, but as regulative principles of the systematic unity of the manifold of empirical knowledge in general, whereby this empirical P 551 knowledge is more adequately secured within its own Limits and more effectively improved than would be possible, in the absence of such ideas, through the employment merely of the principles of the understanding. I shall endeavour to make this clearer. In conformity with these ideas as principles we shall, first, in psychology, under the guidance of inner experience, connect all the appearances, all the actions and receptivity of our mind, as if the mind were a simple substance which persists with personal identity (in this life at least), while its states, to which those of the body belong only as outer conditions, are in continual change. Secondly, in cosmology, we must follow up the conditions of both inner and outer natural appearances, in an enquiry which is to be regarded as never allowing of completion, just as if the series of appearances were in itself endless, without any first or supreme member. We need not, in so doing, deny that, outside all appearances, there are purely intelligible grounds of the appearances; but as we have no knowledge of these whatsoever, we must never attempt to make use of them in our explanations of nature. Thirdly, and finally, in the domain of theology, we must view everything that can belong to the context of possible experience as if this experience formed an absolute but at the same time completely dependent and sensibly conditioned unity, and yet also at the same time as if the sum of all appearances (the sensible world itself) had a single, highest and all-sufficient ground beyond itself, namely, a self-subsistent, original, creative reason. For it is in the light of this idea of a creative reason that we so guide the empirical employment of our reason as to secure its greatest possible extension -- that is, by viewing all objects as if they drew their origin from such an archetype. In other words, we ought not to derive the inner appearances of the soul from a simple thinking substance but from one another, in accordance with the idea of a simple being; we ought not to derive the order and systematic unity of the world from a supreme intelligence, but to obtain from the idea of a supremely wise cause the rule according to which reason in connecting empirical causes and effects in the world may be employed to best advantage, and in such manner as to secure satisfaction of its own demands. Now there is nothing whatsoever to hinder us from as- P 552 suming these ideas to be also objective, that is, from hypostatising them -- except in the case of the cosmological ideas, where reason, in so proceeding, falls into antinomy. The psychological and theological ideas contain no antinomy, and involve no contradiction. How, then, can anyone dispute their [possible] objective reality? He who denies their possibility must do so with just as little knowledge [of this possibility] as we can have in affirming it. It is not, however, a sufficient ground for assuming anything, that there is no positive hindrance to our so doing; we are not justified in introducing thought-entities which transcend all our concepts, though without contradicting them, as being real and determinate objects, merely on the authority of a speculative reason that is bent upon completing the tasks which it has set itself. They ought not to be assumed as existing in themselves, but only as having the reality of a schema -- the schema of the regulative principle of the systematic unity of all knowledge of nature. They should be regarded only as analoga of real things, not as in themselves real things. We remove from the object of the idea the conditions which limit the concept provided by our understanding, but which also alone make it possible for us to have a determinate concept of anything. What we then think is a something of which, as it is in itself, we have no concept whatsoever, but which we none the less represent to ourselves as standing to the sum of appearances in a relation analogous to that in which appearances stand to one another. If, in this manner, we assume such ideal beings, we do not really extend our knowledge beyond the objects of possible experience; we extend only the empirical unity of such experience, by means of the systematic unity for which the schema is provided by the idea -- an idea which has therefore no claim to be a constitutive, but only a regulative principle. For to allow that we posit a thing, a something, a real being, corresponding to the idea, is not to say that we profess to extend our knowledge of things by means of transcendental concepts. For this being is posited only in the idea and not in itself; and therefore only as expressing the systematic P 553 unity which is to serve as a rule for the empirical employment of reason. It decides nothing in regard to the ground of this unity or as to what may be the inner character of the being on which as cause the unity depends. Thus the transcendental, and the only determinate, concept which the purely speculative reason gives us of God is, in the strictest sense, deistic; that is, reason does not determine the objective validity of such a concept, but yields only the idea of something which is the ground of the highest and necessary unity of all empirical reality. This something we cannot think otherwise than on the analogy of a real substance that, in conformity with laws of reason, is the cause of all things. This, indeed, is how we must think it, in so far as we venture to think it as a special object, and do not rather remain satisfied with the mere idea of the regulative principle of reason, leaving aside the completion of all conditions of thought as being too surpassingly great for the human understanding. The latter procedure is, however, inconsistent with the pursuit of that complete systematic unity in our knowledge to which reason at least sets no limits. This, then, is how matters stand: if we assume a divine being, we have indeed no concept whatsoever either of the inner possibility of its supreme perfection or of the necessity of its existence; but, on the other hand, we are in a position to give a satisfactory answer to all those questions which relate to the contingent, and to afford reason the most complete satisfaction in respect to that highest unity after which it is seeking in its empirical employment. The fact, however, that we are unable to satisfy reason in respect to the assumption itself, shows that it is the speculative interest of reason, not any insight, which justifies it in thus starting from a point that lies so far above its sphere; and in endeavouring, by this device, to survey its objects as constituting a complete whole. We here come upon a distinction bearing on the procedure of thought in dealing with one and the same assumption, a distinction which is somewhat subtle, but of great importance in transcendental philosophy. I may have sufficient ground to assume something, in a relative sense (suppositio relativa), and yet have no right to assume it absolutely (suppositio absoluta). P 554 This distinction has to be reckoned with in the case of a merely regulative principle. We recognise the necessity of the principle, but have no knowledge of the source of its necessity; and in assuming that it has a supreme ground, we do so solely in order to think its universality more determinately. Thus, for instance, when I think as existing a being that corresponds to a mere idea, indeed to a transcendental idea, I have no right to assume any such thing as in itself existing, since no concepts through which I am able to think any object as determined suffice for such a purpose -- the conditions which are required for the objective validity of my concepts being excluded by the idea itself. The concepts of reality, substance, causality, even that of necessity in existence, apart from their use in making possible the empirical knowledge of an object, have no meaning whatsoever, such as might serve to determine any object. They can be employed, therefore, to explain the possibility of things in the world of sense, but not to explain the possibility of the universe itself. Such a ground of explanation would have to be outside the world, and could not therefore be an object of a possible experience. None the less, though I cannot assume such an inconceivable being [as existing] in itself, I may yet assume it as the object of a mere idea, relatively to the world of sense. For if the greatest possible empirical employment of my reason rests upon an idea (that of systematically complete unity, which I shall presently be defining more precisely), an idea which, although it can never itself be adequately exhibited in experience, is yet indispensably necessary in order that we may approximate to the highest possible degree of empirical unity, I shall not only be entitled, but shall also be constrained, to realise this idea, that is, to posit for it a real object. But I may posit it only as a something which I do not at all know in itself, and to which, as a ground of that systematic unity, I ascribe, in relation to this unity, such properties as are analogous to the concepts employed by the understanding in the empirical sphere. Accordingly, in analogy with realities in the world, that is, with substances, with causality and with necessity, I think a being which possesses all this in the highest perfection; and since this idea depends merely on my reason, I can think this being as self-subsistent reason, P 555 which through ideas of the greatest harmony and unity is the cause of the universe. I thus omit all conditions which might limit the idea, solely in order, under countenance of such an original ground, to make possible systematic unity of the manifold in the universe, and thereby the greatest possible empirical employment of reason. This I do by representing all connections as if they were the ordinances of a supreme reason, of which our reason is but a faint copy. I then proceed to think this supreme being exclusively through concepts which, properly, are applicable only in the world of sense. But since I make none but a relative use of the transcendental assumption, namely, as giving the substratum of the greatest possible unity of experience, I am quite in order in thinking a being which I distinguish from the world of sense, through properties which belong solely to that world. For I do not seek, nor am I justified in seeking, to know this object of my idea according to what it may be in itself. There are no concepts available for any such purpose; even the concepts of reality, substance, causality, nay, even that of necessity in existence, lose all meaning, and are empty titles for [possible] concepts, themselves entirely without content, when we thus venture with them outside the field of the senses. I think to myself merely the relation of a being, in itself completely unknown to me, to the greatest possible systematic unity of the universe, solely for the purpose of using it as a schema of the regulative principle of the greatest possible empirical employment of my reason. If it be the transcendental object of our idea that we have in view, it is obvious that we cannot thus, in terms of the concepts of reality, substance, causality, etc. , presuppose its reality in itself, since these concepts have not the least application to anything that is entirely distinct from the world of sense. The supposition which reason makes of a supreme being, as the highest cause, is, therefore relative only; it is devised solely for the sake of systematic unity in the world of sense, and is a mere something in idea, of which, as it may be in itself, we have no concept. This explains why, in relation to what is given to the senses as existing, we require the idea of a primordial being necessary in itself, and yet can never form the slightest concept of it or of its absolute necessity. P 556 We are now in a position to have a clear view of the outcome of the whole Transcendental Dialectic, and accurately to define the final purpose of the ideas of pure reason, which become dialectical only through heedlessness and misapprehension. Pure reason is in fact occupied with nothing but itself. It can have no other vocation. For what is given to it does not consist in objects that have to be brought to the unity of the empirical concept, but in those modes of knowledge supplied by the understanding that require to be brought to the unity of the concept of reason -- that is, to unity of connection in conformity with a principle. The unity of reason is the unity of system; and this systematic unity does not serve objectively as a principle that extends the application of reason to objects, but subjectively as a maxim that extends its application to all possible empirical knowledge of objects. Nevertheless, since the systematic connection which reason can give to the empirical employment of the understanding not only furthers its extension, but also guarantees its correctness, the principle of such systematic unity is so far also objective, but in an indeterminate manner (principium vagum). It is not a constitutive principle that enables us to determine anything in respect of its direct object, but only a merely regulative principle and maxim, to further and strengthen in infinitum (indeterminately) the empirical employment of reason -- never in any way proceeding counter to the laws of its empirical employment, and yet at the same time opening out new paths which are not within the cognisance of the understanding. But reason cannot think this systematic unity otherwise than by giving to the idea of this unity an object; and since experience can never give an example of complete systematic unity, the object which we have to assign to the idea is not such as experience can ever supply. This object, as thus entertained by reason (ens rationis ratiocinatae), is a mere idea; it is not assumed as a something that is real absolutely and in itself, but is postulated only problematically (since we cannot reach it through any of the concepts of the understanding) in order that we may view all connection of the things of the world of sense as if they had their ground in such a being. In thus proceeding, our sole purpose is to secure that systematic unity which is indispensable to reason, and P 557 which while furthering in every way the empirical knowledge obtainable by the understanding can never interfere to hinder or obstruct it. We misapprehend the meaning of this idea if we regard it as the assertion or even as the assumption of a real thing, to which we may proceed to ascribe the ground of the systematic order of the world. On the contrary, what this ground which eludes our concepts may be in its own inherent constitution is left entirely undetermined; the idea is posited only as being the point of view from which alone that unity, which is so essential to reason and so beneficial to the understanding, can be further extended. In short, this transcendental thing is only the schema of the regulative principle by which reason, so far as lies in its power, extends systematic unity over the whole field of experience. The first object of such an idea is the 'I' itself, viewed simply as thinking nature or soul. If I am to investigate the properties with which a thinking being is in itself endowed, I must interrogate experience. For I cannot even apply any one of the categories to this object, except in so far as the schema of the category is given in sensible intuition. But I never thereby attain to a systematic unity of all appearances of inner sense. Instead, then, of the empirical concept (of that which the soul actually is), which cannot carry us far, reason takes the concept of the empirical unity of all thought; and by thinking this unity as unconditioned and original, it forms from it a concept of reason, that is, the idea of a simple substance, which, unchangeable in itself (personally identical), stands in association with other real things outside it; in a word, the idea of a simple self- subsisting intelligence. Yet in so doing it has nothing in view save principles of systematic unity in the explanation of the appearances of the soul. It is endeavouring to represent all determinations as existing in a single subject, all powers, so far as possible, as derived from a single fundamental power, all change as belonging to the states of one and the same permanent being, and all appearances in space as completely different from the actions of thought. The simplicity and other properties of substance are intended to be only the schema of this regulative principle, and are not presupposed as being the actual ground of the properties of the soul. For these may rest P 558 on altogether different grounds, of which we can know nothing. The soul in itself could not be known through these assumed predicates, not even if we regarded them as absolutely valid in respect of it. For they constitute a mere idea which cannot be represented in concreto. Nothing but advantage can result from the psychological idea thus conceived, if only we take heed that it is not viewed as more than a mere idea, and that it is therefore taken as valid only relatively to the systematic employment of reason in determining the appearances of our soul. For no empirical laws of bodily appearance, which are of a totally different kind, will then intervene in the explanation of what belongs exclusively to inner sense. No windy hypotheses of generation, extinction, and palingenesis of souls will be permitted. The consideration of this object of inner sense will thus be kept completely pure and will not be confused by the introduction of heterogeneous properties. Also, reason's investigations will be directed to reducing the grounds of explanation in this field, so far as may be possible, to a single principle. All this will be best attained through such a schema, viewed as if it were a real being; indeed it is attainable in no other way. The psychological idea can signify nothing but the schema of a regulative concept. For were I to enquire whether the soul in itself is of spiritual nature, the question would have no meaning. In employing such a concept I not only abstract from corporeal nature, but from nature in general, that is, from all predicates of any possible experience, and therefore from all conditions requisite for thinking an object for such a concept; yet only as related to an object can the concept be said to have a meaning. The second regulative idea of merely speculative reason is the concept of the world in general. For nature is properly the only given object in regard to which reason requires regulative principles. This nature is twofold, either thinking or corporeal. To think the latter, so far as regards its inner possibility, that is, to determine the application of the categories to it, we need no idea, that is, no representation which transcends experience. Nor, indeed, is any idea possible in this connection, since in dealing with corporeal nature we are guided solely by sensible intuition. The case is different from that of the fundamental psychological concept ('I'), which P 559 contains a priori a certain form of thought, namely, the unity of thought. There therefore remains for pure reason nothing but nature in general, and the completeness of the conditions in nature in accordance with some principle. The absolute totality of the series of these conditions, in the derivation of their members, is an idea which can never be completely realised in the empirical employment of reason, but which yet serves as a rule that prescribes how we ought to proceed in dealing with such series, namely, that in explaining appearances, whether in their regressive or in their ascending order, we ought to treat the series as if it were in itself infinite, that is, as if it proceeded in indefinitum. When, on the other hand, reason is itself regarded as the determining cause, as in [the sphere of] freedom, that is to say, in the case of practical principles, we have to proceed as if we had before us an object, not of the senses, but of the pure understanding. In this practical sphere the conditions are no longer in the series of appearances; they can be posited outside the series, and the series of states can therefore be regarded as if it had an absolute beginning, through an intelligible cause. All this shows that the cosmological ideas are nothing but simply regulative principles, and are very far from positing, in the manner of constitutive principles, an actual totality of such series. The fuller treatment of this subject will be found in the chapter on the antinomy of pure reason. The third idea of pure reason, which contains a merely relative supposition of a being that is the sole and sufficient cause of all cosmological series, is the idea of God. We have not the slightest ground to assume in an absolute manner (to suppose in itself) the object of this idea; for what can enable us to believe in or assert a being of the highest perfection and one absolutely necessary by its very nature, merely on the basis of its concept, or if we did how could we justify our procedure? It is only by way of its relation to the world that we can attempt to establish the necessity of this supposition; and it then becomes evident that the idea of such a being, like all speculative ideas, seeks only to formulate the command of reason, that all connection in the world be viewed in accordance with the principles of a systematic unity -- as if all such connection had its source in one single all-embracing being, as the supreme and P 560 all-sufficient cause. It is thus evident that reason has here no other purpose than to prescribe its own formal rule for the extension of its empirical employment, and not any extension beyond all limits of empirical employment. Consequently it is evident that this idea does not, in any concealed fashion, involve any principle that claims, in its application to possible experience, to be constitutive in character. This highest formal unity, which rests solely on concepts of reason, is the purposive unity of things. The speculative interest of reason makes it necessary to regard all order in the world as if it had originated in the purpose of a supreme reason. Such a principle opens out to our reason, as applied in the field of experience, altogether new views as to how the things of the world may be connected according to teleological laws, and so enables it to arrive at their greatest systematic unity. The assumption of a supreme intelligence, as the one and only cause of the universe, though in the idea alone, can therefore always benefit reason and can never injure it. Thus if, in studying the shape of the earth (which is round, but somewhat flattened), of the mountains, seas, etc. , we assume it to be the outcome of wise purposes on the part of an Author of the world, we are enabled to make in this way a number of discoveries. And provided we restrict ourselves to a merely regulative use of this principle, even error cannot do us any serious harm. For the worst that can happen would be that where we expected a teleological connection (nexus finalis), we find only a mechanical or physical connection (nexus effectivus). In such a case, we merely fail to find the additional unity; we do not destroy the unity upon which reason insists in its empirical employment. ++ The advantage arising from the spherical shape of the earth is well known. But few are aware that its spheroidal flattening alone prevents the continental elevations, or even the smaller hills, thrown up perhaps by earthquakes, from continuously, and indeed quite appreciably in a comparatively short time, altering the position of the axis of the earth. The protuberance of the earth at the equator forms so vast a mountain that the impetus of all the other mountains can never produce any observable effect in changing the position of the earth's axis. And yet, wise as this arrangement is, we feel no scruples in explaining it from the equilibrium of the formerly fluid mass of the earth. P 561 But even a disappointment of this sort cannot affect the teleological law itself, in its general bearing. For although an anatomist can be convicted of error when he assigns to some member of an animal body an end which it can be clearly shown not to subserve, it is yet quite impossible to prove in any given case that an arrangement of nature, be it what it may, subserves no end whatsoever. Accordingly, medical physiology extends its very limited empirical knowledge of the ends served by the articulation of an organic body, by resorting to a principle for which pure reason has alone been responsible; and it carries this principle so far as to assume confidently, and with general approval, that everything in an animal has its use, and subserves some good purpose. If this assumption be treated as constitutive it goes much further than observation has thus far been able to justify; and we must therefore conclude that it is nothing more than a regulative principle of reason, to aid us in securing the highest possible systematic unity, by means of the idea of the purposive causality of the supreme cause of the world -- as if this being, as supreme intelligence, acting in accordance with a supremely wise purpose, were the cause of all things. If, however, we overlook this restriction of the idea to a merely regulative use, reason is led away into mistaken paths. For it then leaves the ground of experience, which alone can contain the signs that mark out its proper course, and ventures out beyond it to the incomprehensible and unsearchable, rising to dizzy heights where it finds itself entirely cut off from all possible action in conformity with experience. The first error which arises from our using the idea of a supreme being in a manner contrary to the nature of an idea, that is, constitutively, and not regulatively only, is the error of ignava ratio. ++ This was the title given by the ancient dialecticians to a sophistical argument, which ran thus: If it is your fate to recover from this illness, you will recover, whether you employ a physician or not. Cicero states that this mode of argument has been so named, because, if we conformed to it, reason would be left without any use in life. On the same ground I apply the name also to the sophistical argument of pure reason. P 561 We may so entitle every principle which makes P 562 us regard our investigation into nature, on any subject, as absolutely complete, disposing reason to cease from further enquiry, as if it had entirely succeeded in the task which it had set itself. Thus the psychological idea, when it is employed as a constitutive principle to explain the appearances of our soul, and thereby to extend our knowledge of the self beyond the limits of experience (its state after death), does indeed simplify the task of reason; but it interferes with, and entirely ruins, our use of reason in dealing with nature under the guidance of our experiences. The dogmatic spiritualist explains the abiding and unchanging unity of a person throughout all change of state, by the unity of the thinking substance, of which, as he believes, he has immediate perception in the 'I'; or he explains the interest which we take in what can happen only after our death, by means of our consciousness of the immaterial nature of the thinking subject; and so forth. He thus dispenses with all empirical investigation of the cause of these inner appearances, so far as that cause is to be found in physical grounds of explanation; and to his own great convenience, though at the sacrifice of all real insight, he professes, in reliance upon the assumed authority of a transcendent reason, to have the right to ignore those sources of knowledge which are immanent in experience. These detrimental consequences are even more obvious in the dogmatic treatment of our idea of a supreme intelligence, and in the theological system of nature (physico-theology) which is falsely based upon it. For in this field of enquiry, if instead of looking for causes in the universal laws of material mechanism, we appeal directly to the unsearchable decree of supreme wisdom, all those ends which are exhibited in nature, together with the many ends which are only ascribed by us to nature, make our investigation of the causes a very easy task, and so enable us to regard the labour of reason as completed, when, as a matter of fact, we have merely dispensed with its employment -- an employment which is wholly dependent for guidance upon the order of nature and the series of its alterations, in accordance with the universal laws which they are found to exhibit. This error can be avoided, if we consider from the teleological point of view not merely certain parts of nature, such as the distribution P 563 of land, its structure, the constitution and location of the mountains, or only the organisation of the vegetable and animal kingdoms, but make this systematic unity of nature completely universal, in relation to the idea of a supreme intelligence. For we then treat nature as resting upon a purposiveness, in accordance with universal laws, from which no special arrangement is exempt, however difficult it may be to establish this in any given case. We then have a regulative principle of the systematic unity of teleological connection -- a connection which we do not, however, predetermine. What we may presume to do is to follow out the physico-mechanical connection in accordance with universal laws in the hope of discovering what the teleological connection actually is. In this way alone can the principle of purposive unity aid always in extending the employment of reason in reference to experience without being in any instance prejudicial to it. The second error arising from the misapprehension of the above principle of systematic unity is that of perversa ratio (husteron proteron). The idea of systematic unity should be used only as a regulative principle to guide us in seeking for such unity in the connection of things, according to universal laws of nature; and we ought, therefore, to believe that we have approximated to completeness in the employment of the principle only in proportion as we are in a position to verify such unity in empirical fashion -- a completeness which is never, of course, attainable. Instead of this the reverse procedure is adopted. The reality of a principle of purposive unity is not only presupposed but hypostatised; and since the concept of a supreme intelligence is in itself completely beyond our powers of comprehension, we proceed to determine it in an anthropomorphic manner, and so to impose ends upon nature, forcibly and dictatorially, instead of pursuing the more reasonable course of searching for them by the path of physical investigation. And thus teleology, which is intended to aid us merely in completing the unity of nature in accordance with universal laws, not only tends to abrogate such unity, but also prevents reason from carrying out its own professed purpose, that of proving from nature, in conformity with these laws, the existence of a supreme intelligent cause. P 564 For if the most complete purposiveness cannot be presupposed a priori in nature, that is, as belonging to its essence, how can we be required to search for it, and through all its gradations to approximate to the supreme perfection of an Author of all things, a perfection that, as absolutely necessary, must be knowable a priori? The regulative principle prescribes that systematic unity as a unity in nature, which is not known merely empirically but is presupposed a priori (although in an indeterminate manner), be presupposed absolutely, and consequently as following from the essence of things. If, however, I begin with a supreme purposive being as the ground of all things, the unity of nature is really surrendered, as being quite foreign and accidental to the nature of things, and as not capable of being known from its own universal laws. There then arises a vicious circle; we are assuming just that very point which is mainly in dispute. To take the regulative principle of the systematic unity of nature as being a constitutive principle, and to hypostatise, and presuppose as a cause, that which serves, merely in idea, as the ground of the consistent employment of reason, is simply to confound reason. The investigation of nature takes its own independent course, keeping to the chain of natural causes in conformity with their universal laws. It does indeed, in so doing, proceed in accordance with the idea of an Author of the universe, but not in order to deduce therefrom the purposiveness for which it is ever on the watch, but in order to obtain knowledge of the existence of such an Author from this purposiveness. And by seeking this purposiveness in the essence of the things of nature, and so far as may be possible in the essence of things in general, it seeks to know the existence of this supreme being as absolutely necessary. Whether this latter enterprise succeed or not, the idea remains always true in itself, and justified in its use, provided it be restricted to the conditions of a merely regulative principle. Complete purposive unity constitutes what is, in the absolute sense, perfection. If we do not find this unity in the essence of the things which go to constitute the entire object of experience, that is, of all our objectively valid knowledge, and therefore do not find it in the universal and necessary laws of nature, how can we profess to infer directly from this unity the P 565 idea of a supreme and absolutely necessary perfection of an original being, as the source of all causality? The greatest possible systematic unity, and consequently also purposive unity, is the training school for the use of reason, and is indeed the very foundation of the possibility of its greatest possible employment. The idea of such unity is, therefore, inseparably bound up with the very nature of our reason. This same idea is on that account legislative for us; and it is therefore very natural that we should assume a corresponding legislative reason (intellectus archetypus), from which, as the object of our reason, all systematic unity of nature is to be derived. In discussing the antinomy of pure reason we have stated that the questions propounded by pure reason must in every case admit of an answer, and that in their regard it is not permissible to plead the limits of our knowledge (a plea which in many questions that concern nature is as unavoidable as it is relevant). For we are not here asking questions in regard to the nature of things, but only such questions as arise from the very nature of reason, and which concern solely its own inner constitution. We are now in a position to confirm this assertion -- which at first sight may have appeared rash -- so far as regards the two questions in which pure reason is most of all interested; and thus finally to complete our discussion of the dialectic of pure reason. If, in connection with a transcendental theology, we ask, first, whether there is anything distinct from the world, which contains the ground of the order of the world and of its connection in accordance with universal laws, the answer is that there undoubtedly is. For the world is a sum of appearances; and there must therefore be some transcendental ground of the appearances, that is, a ground which is thinkable only by the pure understanding. If, secondly, the question be, whether this being is substance, of the greatest reality, necessary, etc. , ++ After what I have already said regarding the psychological idea and its proper vocation, as a principle for the merely regulative employment of reason, I need not dwell at any length upon the transcendental illusion by which the systematic unity of all the manifoldness of inner sense is hypostatised. The procedure is very similar to that which is under discussion in our criticism of the theological ideal. P 566 we reply that this question is entirely without meaning. For all categories through which we can attempt to form a concept of such an object allow only of empirical employment, and have no meaning whatsoever when not applied to objects of possible experience, that is, to the world of sense. Outside this field they are merely titles of concepts, which we may admit, but through which [in and by themselves] we can understand nothing. If, thirdly, the question be, whether we may not at least think this being, which is distinct from the world, in analogy with the objects of experience, the answer is: certainly, but only as object in idea and not in reality, namely, only as being a substratum, to us unknown, of the systematic unity, order, and purposiveness of the arrangement of the world -- an idea which reason is constrained to form as the regulative principle of its investigation of nature. Nay, more, we may freely, without laying ourselves open to censure, admit into this idea certain anthropomorphisms which are helpful to the principle in its regulative capacity. For it is always an idea only, which does not relate directly to a being distinct from the world, but to the regulative principle of the systematic unity of the world, and only by means of a schema of this unity, namely, through the schema of a supreme intelligence which, in originating the world, acts in accordance with wise purposes. What this primordial ground of the unity of the world may be in itself, we should not profess to have thereby decided, but only how we should use it, or rather its idea, in relation to the systematic employment of reason in respect of the things of the world. But the question may still be pressed: Can we, on such grounds, assume a wise and omnipotent Author of the world? Undoubtedly we may; and we not only may, but must, do so. But do we then extend our knowledge beyond the field of possible experience? By no means. All that we have done is merely to presuppose a something, a merely transcendental object, of which, as it is in itself, we have no concept whatsoever. It is only in relation to the systematic and purposive ordering of the world, which, if we are to study nature, we are constrained to presuppose, that we have thought this unknown being by analogy with an intelligence (an empirical concept); that is, have endowed it, in respect of the ends and perfection P 567 which are to be grounded upon it, with just those properties which, in conformity with the conditions of our reason, can be regarded as containing the ground of such systematic unity. This idea is thus valid only in respect of the employment of our reason in reference to the world. If we ascribed to it a validity that is absolute and objective, we should be forgetting that what we are thinking is a being in idea only; and in thus taking our start from a ground which is not determinable through observation of the world, we should no longer be in a position to apply the principle in a manner suited to the empirical employment of reason. But, it will still be asked, can I make any such use of the concept and of the presupposition of a supreme being in the rational consideration of the world? Yes, it is precisely for this purpose that reason has resorted to this idea. But may I then proceed to regard seemingly purposive arrangements as purposes, and so derive them from the divine will, though, of course, mediately through certain special natural means, themselves established in furtherance of that divine will? Yes, we can indeed do so; but only on condition that we regard it as a matter of indifference whether it be asserted that divine wisdom has disposed all things in accordance with its supreme ends, or that the idea of supreme wisdom is a regulative principle in the investigation of nature and a principle of its systematic and purposive unity, in accordance with universal laws, even in those cases in which we are unable to detect that unity. In other words, it must be a matter of complete indifference to us, when we perceive such unity, whether we say that God in his wisdom has willed it to be so, or that nature has wisely arranged it thus. For what has justified us in adopting the idea of a supreme intelligence as a schema of the regulative principle is precisely this greatest possible systematic and purposive unity -- a unity which our reason has required as a regulative principle that must underlie all investigation of nature. The more, therefore, we discover purposiveness in the world, the more fully is the legitimacy of our idea confirmed. But since the sole aim of that principle was to guide us in seeking a necessary unity of nature, and that in the greatest possible degree, while we do indeed, P 568 in so far as we attain that unity, owe it to the idea of a supreme being, we cannot, without contradicting ourselves, ignore the universal laws of nature -- with a view to discovering which the idea was alone adopted -- and look upon this purposiveness of nature as contingent and hyperphysical in its origin. For we were not justified in assuming above nature a being with those qualities, but only in adopting the idea of such a being in order to view the appearances as systematically connected with one another in accordance with the principle of a causal determination. For the same reasons, in thinking the cause of the world, we are justified in representing it in our idea not only in terms of a certain subtle anthropomorphism (without which we could not think anything whatsoever in regard to it), namely, as a being that has understanding, feelings of pleasure and displeasure, and desires and volitions corresponding to these, but also in ascribing to it a perfection which, as infinite, far transcends any perfection that our empirical knowledge of the order of the world can justify us in attributing to it. For the regulative law of systematic unity prescribes that we should study nature as if systematic and purposive unity, combined with the greatest possible manifoldness, were everywhere to be met with, in infinitum. For although we may succeed in discovering but little of this perfection of the world, it is nevertheless required by the legislation of our reason that we must always search for and surmise it; and it must always be beneficial, and can never be harmful, to direct our investigations into nature in accordance with this principle. But it is evident that in this way of representing the principle as involving the idea of a supreme Author, I do not base the principle upon the existence and upon the knowledge of such a being, but upon its idea only, and that I do not really derive anything from this being, but only from the idea of it -- that is, from the nature of the things of the world, in accordance with such an idea. A certain, unformulated consciousness of the true use of this concept of reason seems indeed to have inspired the modest and reasonable language of the philosophers of all times, since they speak of the wisdom and providence of nature and of divine wisdom, just as if nature and divine wisdom were P 569 equivalent expressions -- indeed, so long as they are dealing solely with speculative reason, giving preference to the former mode of expression, on the ground that it enables us to avoid making profession of more than we are justified in asserting, and that it likewise directs reason to its own proper field, namely, nature. Thus pure reason, which at first seemed to promise nothing less than the extension of knowledge beyond all limits of experience, contains, if properly understood, nothing but regulative principles, which, while indeed prescribing greater unity than the empirical employment of understanding can achieve, yet still, by the very fact that they place the goal of its endeavours at so great a distance, carry its agreement with itself, by means of systematic unity, to the highest possible degree. But if, on the other hand, they be misunderstood, and be treated as constitutive principles of transcendent knowledge, they give rise, by a dazzling and deceptive illusion, to persuasion and a merely fictitious knowledge, and therewith to contradictions and eternal disputes. *** Thus all human knowledge begins with intuitions, proceeds from thence to concepts, and ends with ideas. Although in respect of all three elements it possesses a priori sources of knowledge, which on first consideration seem to scorn the limits of all experience, a thoroughgoing critique convinces us that reason, in its speculative employment, can never with these elements transcend the field of possible experience, and that the proper vocation of this supreme faculty of knowledge is to use all methods, and the principles of these methods, solely for the purpose of penetrating to the innermost secrets of nature, in accordance with every possible principle of unity -- that of ends being the most important -- but never to soar beyond its limits, outside which there is for us nothing but empty space. The critical examination, as carried out in the Transcendental Analytic, of all propositions which may seem to extend our knowledge beyond actual experience, has doubtless sufficed to convince us that they can never lead to anything more than a possible experience. Were it not that we are suspicious of abstract and general doctrines, however clear, P 570 and were it not that specious and alluring prospects tempt us to escape from the compulsion which these doctrines impose, we might have been able to spare ourselves the laborious interrogation of all those dialectical witnesses that a transcendent reason brings forward in support of its pretensions. For we should from the start have known with complete certainty that all such pretensions, while perhaps honestly meant, must be absolutely groundless, inasmuch as they relate to a kind of knowledge to which man can never attain. But there is no end to such discussions, unless we can penetrate to the true cause of the illusion by which even the wisest are deceived. Moreover, the resolution of all our transcendent knowledge into its elements (as a study of our inner nature) is in itself of no slight value, and to the philosopher is indeed a matter of duty. Accordingly, fruitless as are all these endeavours of speculative reason, we have none the less found it necessary to follow them up to their primary sources. And since the dialectical illusion does not merely deceive us in our judgments, but also, because of the interest which we take in these judgments, has a certain natural attraction which it will always continue to possess, we have thought it advisable, with a view to the prevention of such errors in the future, to draw up in full detail what we may describe as being the records of this lawsuit, and to deposit them in the archives of human reason.