One of the clearest and most acute minds among the philosophers of the Illumination was the deist Hermann Samuel Reimarus[1] (1694-1768), from 1728 professor in Hamburg. He attacks atheism, in whatever form it may present itself, with as much zeal and conviction as he shows in breaking down the belief in revelation by his inexorable criticism (in his Defense, communicated in ma.n.u.script to a few friends only). He obtains his weapons for this double battle from the Wolffian philosophy. The existence of an extramundane deity is proved by the purposive arrangement of the world, especially of organisms, which aims at the good-not merely of man, as the majority of the physico-theologists have believed, but-of all living creatures. To believe in a special revelation, i.e., a miracle, in addition to such a revelation of G.o.d as this, which is granted to all men, and is alone necessary to salvation, is to deny the perfection of G.o.d, and to do violence to the immutability of his providence. To these general considerations against the credibility of positive revelation are to be added, as special arguments against the Jewish and Christian revelations, the untrustworthiness of human testimony in general, the contradictions in the biblical writings, the uncertainty of their meaning, and the moral character of the persons regarded as messengers of G.o.d, whose teachings, precepts, and deeds in no wise correspond to their high mission. Jewish history is a "tissue of sheer follies, shameful deeds, deceptions, and cruelties, the chief motives of which were self-interest and l.u.s.t for power." The New Testament is also the work of man; all talk of divine inspiration, an idle delusion, the resurrection of Christ, a fabrication of the disciples; and the Protestant system, with its dogmas of the Trinity, the fall of man, original sin, the incarnation, vicarious atonement, and eternal punishment, contrary to reason. The advance of Reimarus beyond Wolff consists in the consistent application of the criteria for the divine character of revelation, which Wolff had set up without making a positive, not to speak of a negative, use of them. His weakness[2] consists in the fact that, on the one hand, he contented himself with a rationalistic interpretation of the biblical narratives, instead of pus.h.i.+ng on-as Semler did after him at Halle (1725-91)-to a historical criticism of the sources, and, on the other, held fast to the alternative common to all the deists, "Either divine or human, either an actual event or a fabrication," without any suspicion of that great intermediate region of religious myth, of the involuntary and pregnant inventions of the popular fancy.
[Footnote 1: H.S. Reimarus: Discussions on the Chief Truths of Natural Religion, 1754; General Consideration of the Instincts of Animals, 1762; Apology or Defense for the Rational Wors.h.i.+pers of G.o.d. Fragments of the last of these works, which was kept secret during its author's life, were published by Lessing (the well-known "Wolffenb.u.t.tel Fragments," from 1774). A detailed table of contents is to be found in Reimarus und seine Schutzschrift, 1862, by D. Fr. Strauss, included in the fifth volume of his Gesammelte Schriften.]
[Footnote 2: Cf. O. Pfleiderer, Philosophy of Religion, vol. i. p. 102, p. 106 seq.]
The philosophico-religious standpoint of G.E. Lessing (1729-81), in whom the Illumination reached its best fruitage, was less one-sided. Apart from the important aesthetic impulses which flowed from the Laoc.o.o.n (1766) and the Hamburg Dramaturgy (1767-69), his philosophical significance rests on two ideas, which have had important consequences for the religious conceptions of the nineteenth century: the speculative interpretation of certain dogmas (the Trinity, etc.), and the application of the Leibnitzian idea of development to the history of the positive religions. By both of these he prepared the way for Hegel. In regard to his relation to his predecessors, Lessing sought to mediate between the pantheism of Spinoza and the individualism of Leibnitz; and in his comprehension of the latter showed himself far superior to the Wolffians. He can be called a Spinozist only by those who, like Jacobi, have this t.i.tle ready for everyone who expresses himself against a transcendent, personal G.o.d, and the unconditional freedom of the will. Moreover, in view of his critical and dialectical, rather than systematic, method of thinking, we must guard against laying too great stress on isolated statements by him.[1]
[Footnote 1: A caution which Gideon Spicker (Lessings Weltanschauung, 1883) counsels us not to forget, even in view of the oft cited avowal of determinism, "I thank G.o.d that I must, and that I must the best." Among the numerous treatises on Lessing we may note those by G.E. Schwarz (1854), and Zeller (in Sybel's Historische Zeitschrift, 1870, incorporated in the second collection of Zeller's Vortrage und Abhandlungen, 1877); and on his theological position, that of K. Fischer on Lessing's Nathan der Weise, 1864, as well as J.H. Witte's Philosophie unserer Dichterheroen, vol. i. (Lessing and Herder), 1880. [Cf. in English, Sime, 2 vols., 1877, and Encyclopedia Britannica, vol. xiv. pp, 478-482.-TR.]]
Lessing conceives the Deity as the supreme, all-comprehensive, living unity, which excludes neither a certain kind of plurality nor even a certain kind of change; without life and action, without the experience of changing states, the life of G.o.d would be miserably wearisome. Things are not out of, but in him; nevertheless (as "contingent") they are distinct from him. The Trinity must be understood in the sense of immanent distinctions. G.o.d has conceived himself, or his perfections, in a twofold manner: he conceived them as united and himself as their sum, and he conceived them as single. Now G.o.d's thinking is creation, his ideas actualities. By conceiving his perfections united he created his eternal image, the Son of G.o.d; the bond between G.o.d representing and G.o.d represented, between Father and Son, is the Holy Spirit. But when he conceived his perfections singly he created the world, in which these manifest themselves divided among a continuous series of particular beings. Every individual is an isolated divine perfection; the things in the world are limited G.o.ds, all living, all with souls, and of a spiritual nature, though in different degrees. Development is everywhere; at present the soul has five senses, but very probably it once had less than five, and in the future it will have more. At first the actions of men were guided by obscure instinct; gradually the reason obtained influence over the will, and one day will govern it completely through its clear and distinct cognitions. Thus freedom is attained in the course of history-the rational and virtuous man consciously obeys the divine order of the world, while he who is unfree obeys unconsciously.
Lessing shares with the deistic Illumination the belief in a religion of reason, whose basis and essential content are formed by morality; but he rises far above this level in that he regards the religion of reason not as the beginning but as the goal of the development, and the positive religions as necessary transition stages in its attainment. As natural religion differs in each individual according to his feelings and powers, without positive enactments there would be no unity and community in religious matters. Nevertheless the statutory and historical element is not a graft from without, but a sh.e.l.l organically grown around natural religion, indispensable for its development, and to be removed but gradually and by layers-when the inclosed kernel has become ripe and firm. The history of religions is an education of the human race through divine revelation; so teaches his small but thoughtful treatise of 1780.[1] As the education of the individual man puts nothing extraneous into him, but only gives him more quickly and easily that which he could have reached of himself, so human reason is illuminated by revelation concerning things to which it could have itself attained, only that without G.o.d's help the process would have been longer and more difficult-perhaps it would have wandered about for many millions of years in the errors of polytheism, if G.o.d had not been pleased by a single stroke (his revelation to Moses) to give it a better direction. And as the teacher does not impart everything to the pupil at once, but considers the state of development reached by him at each given period, so G.o.d in his revelation observes a certain order and measure. To the rude Jewish people he revealed himself first as a national G.o.d, as the G.o.d of their fathers; they had to wait for the Persians to teach them that the G.o.d whom they had hitherto wors.h.i.+ped as the most powerful among other G.o.ds was the only one. Although this lowest stage in the development of religion lacked the belief in immortality, yet it must not be lightly valued; let us acknowledge that it was an heroic obedience for men to observe the laws of G.o.d simply because they are the laws of G.o.d, and not because of temporal or future rewards! The first practical teacher of immortality was Christ; with him the second age of religion begins: the first good book of elementary instruction, the Old Testament, from which man had hitherto learned, was followed by the second, better one, the New Testament. As we now can dispense with the first primer in regard to the doctrine of the unity of G.o.d, and as we gradually begin to be able to dispense with the second in regard to the doctrine of the immortality of the soul, so this New Testament may easily contain still further truths, which for the present we wonder at as revelations, until the reason shall learn to derive them from other truths already established. Lessing himself makes an attempt at a philosophical interpretation of the dogmas of the Trinity (see above), of original sin, and of atonement. Such an advance from faith to knowledge, such a development of revealed truths into proved truths of reason, is absolutely necessary. We cannot dispense with the truths of revelation, but we must not remain content with simply believing them, but must endeavor to comprehend them; for they have been revealed in order that they may become rational. They are, as it were, the sum which the teacher of arithmetic tells his pupils beforehand so that they may guide themselves by it; but if they content themselves with this solution-which was given merely as a guide-they would never learn to calculate. Hand in hand with the advance of the understanding goes the progress of the will. Future recompenses, which the New Testament promises as rewards of virtue, are means of education, and will gradually fall into disuse: in the highest stage, the stage of purity of heart, virtue will be loved and practiced for its own sake, and no longer for the sake of heavenly rewards. Slowly but surely, along devious paths which are yet salutary, we are being led toward that great goal. It will surely come, the time of consummation, when man will do the good because it is good, this time of the new, eternal Gospel, this third age, this "Christianity of reason." Continue, Eternal Providence, thine imperceptible march; let me not despair of thee because it is imperceptible, not even when to me thy steps seem to lead backward. It is not true that the straight line is always the shortest.
[Footnote 1: Die Erziehung des Menschengeschlects.]
With the thought that every individual must traverse the same course as that by which the race attains its perfection, Lessing connects the idea of the transmigration of souls. Why may not the individual man have been present in this world more than once? Is this hypothesis so ridiculous because it is the oldest?
If Lessing abandoned the ranks of the deists by his recognition of the fact that the positive religions contain truth in a gradual process of purification, by his free criticism, on the other hand, he broke with the orthodox, whose idolatrous reverence for the Bible was to him an abomination. The letter is not the spirit, the Bible is not religion, nor yet its foundation, but only its records. Contingent historical truths can never serve as a proof of the necessary truths of reason. Christianity is older than the New Testament.
Already, in the case of Lessing, we may doubt, in view of his historical temper and of certain speculative tendencies, whether he is to be included among the Illuminati. In the case of Kant a decided protest must be raised against such a cla.s.sification. When Hegel numbers him among the philosophers of the Illumination, on account of his lack of rational intuition, and some theologians on account of his religious rationalism, the answer to the former is that Kant did not lack the speculative gift, but only that it was surpa.s.sed by his gift of reflection, and, to the latter, that in regard to the positive element in religion he judged very differently from the deists and appreciated the historical element more justly than they-if not to the same extent as Lessing and Herder. We do not need to lay great stress on the fact that Kant had a lively consciousness that he was making a contribution to thought, and that the Illumination contemplated this new doctrine without comprehending it, in order to recognize that the difference between his efforts and achievements and those of the Illumination is far greater than their kins.h.i.+p. For although Kant is upon common ground with it, in so far as he adheres to its motto, "Have courage to use thine own understanding, become a man, cease to trust thyself to the guidance of others, and free thyself in all fields from the yoke of authority," and, although besides such formal injunctions to freedom of thought, he also shares in certain material tendencies and convictions (the turning from the world to man, the attempt at a synthesis of reason and experience, and the belief in a religion of reason); yet in method and results, he stands like a giant among a race of dwarfs, like one instructed, who judges from principles, among men of opinion, who merely stick results together, a methodical systematizer among well-meaning but impotent eclectics. The philosophy of the Illumination is related to that of Kant as argument to science, as halting mediation to principiant resolution, as patchwork to creation out of full resources, yet at the same time as wish to deed and as negative preparation to positive achievement. It was undeniably of great value to the Kantian criticism that the Illumination had created a point of intersection for the various tendencies of thought, and had brought about the approximation and mutual contact of the opposing systems which then existed, while, at the same time, it had crumbled them to pieces, and thus awakened the need for a new, more firmly and more deeply founded system.
4. The Faith Philosophy.
The philosophers of feeling or faith stand in the same relation to the German Illumination as Rousseau to the French. Here also the rights of feeling are vindicated against those of the knowing reason. Among the distinguished representatives of this anti-rationalistic tendency Hamann led the way, Herder was the most prolific, and Jacobi the clearest. That the fountain of cert.i.tude is to be sought not in discriminating thought, but in intuition, experience, revelation, and tradition; that the highest truths can be felt only and not proved; that all existing things are incomprehensible, because individual-these are convictions which, before Jacobi defended them as based on scientific principles, had been vehemently proclaimed by that singular man, J.G. Hamann (died 1788) of Konigsberg. From an unprinted review by Hamann, Herder drew the objections which his "Metacritique" raises against Kant's Critique of Reason-that the division of matter and form, of sensibility and understanding, is inadmissible; that Kant misunderstood the significance of language, which is just where sensibility and understanding unite, etc.
In Herder[1] (1744-1803: after 1776 Superintendent-General in Weimar) the philosophy of feeling gained a finer, more perspicuous and harmonious nature, who shared Lessing's interest in history and his tendency to hold fast equally to pantheism and to individualism. G.o.d is the all-one, infinite, spiritual (non-personal) primal force, which wholly reveals itself in each thing (G.o.d: Dialogues on the System of Spinoza, 1787). To the life, power, wisdom, and goodness of G.o.d correspond the life and perfection of the universe and of individual creatures, each of which possesses its own irreplaceable value and bears in itself its future in germ. Everywhere, one and the same life in an ascending series of powers and forms with imperceptible transitions. Always, an inner and an outer together; no power without organ, no spirit without a body. As thought is only a higher stage of sensation, which develops from the lower by means of language-reason, like sense, is not a productive but a receptive faculty of knowing, perceiving ("Vernehmen")-so the free process of history is only the continuation and completion of the nature-process (Ideas for the Philosophy of the History of Mankind, 1784 seq.). Man, the last child of nature and her first freedman, is the nodal point where the physical series of events changes into the ethical; the last member of the organisms of earth is at the same time the first in the spiritual development. The mission of history is the unfolding of all the powers which nature has concentrated in man as the compendium of the world; its law, that everywhere on our earth everything be realized that can be realized there; its end, humanity and the harmonious development of all our capacities. As nature forms a single great organism, and from the stone to man describes a connected development, so humanity is a one great individual which pa.s.ses through its several ages, from infancy (the Orient), through boyhood (Eygpt and Phoenicia), youth (Greece), and manhood (Rome), to old age (the Christian world). The spirit stands in the closest dependence upon nature, and nature is concerned in history throughout. The finer organization of his brain, the possession of hands, above all, his erect position, make man, man and endow him with reason. Similarly it is natural conditions, climate, the character of the soil, the surrounding animal and vegetable life, etc., that play an essential part in determining the manners, the characters, and the destinies of nations. The connection of nature with history by means of the concept of development and through the idea that the two merely represent different stages of the same fundamental process, made Herder the forerunner of Sch.e.l.ling.
[Footnote 1: On Herder cf. the biography by R. Haym, 2 vols., 1877, 1885; and the work by Witte which has been referred to above (p. 306, note).]
His polemic against Kant in the Metacritique, 1799 (against the Critique of Pure Reason), and the dialogue Calligone, 1800 (against the Critique of Judgment), is less pleasing. These are neither dignified in tone nor essentially of much importance. In the former the distinction between sensibility and reason is censured, and in the latter the separation of the beautiful from the true and the good, but Kant's theory of aesthetics is for the most part grossly misunderstood. The "disinterested" satisfaction Herder makes a cold satisfaction; the harmonious activity of the cognitive powers, a tedious, apish sport; the satisfaction "without a concept," judgment without ground or cause. The positive elements in his own views are more valuable. Pleasure in mere form, without a concept, and without the idea of an end, is impossible. All beauty must mean or express something, must be a symbol of inner life; its ground is perfection or adaptation. Beauty is that symmetrical union of the parts of a being, in virtue of which it feels well itself and gives pleasure to the observer, who sympathetically shares in this well-being. The charm and value of the Calligone lie more in the warmth and clearness with which the expressive beauty of single natural phenomena is described than in the abstract discussion.
Friedrich Heinrich Jacobi (1743-1819) gave the most detailed statement of the position of the philosophy of feeling, and the most careful proof of it. He was born in Dusseldorf, the son of a manufacturer; until 1794 he lived in his native place and at his country residence in Pempelfort; later he resided in Holstein, and, from 1805, in Munich, where, in 1807-13, he was president of the Academy of Sciences. Of his works, collected in five volumes, 1812-25, we are here chiefly concerned with the letters On the Doctrine of Spinoza, 1785; David Hume on Faith, or Idealism and Realism, 1787; and the treatise On Divine Things, 1811, which called out Sch.e.l.ling's merciless response, Memorial of Jacobi. Besides Hume and Spinoza, the sensationalism of Bonnet and the criticism of Kant had made the most lasting impression on Jacobi. His relation to Kant is neither that of an opponent nor of a supporter and popularizer. He declares himself in accord with Kant's critique of the understanding (the understanding is merely a formal function, one which forms and combines concepts only, but does not guarantee reality, one to which the material of thought must be given from elsewhere and for which the suprasensible remains unattainable); in regard to the critique of reason he raises the objection that it; makes the Ideas mere postulates, which possess no guarantee for their reality. The critique of sensibility appears to him still more unsatisfactory, as it does not explain the origin of sensations. Without the concept of the "thing-in-itself" one cannot enter the Kantian philosophy, and with it one cannot remain there. Fichte has drawn the correct conclusion from the Kantian premises; idealism is the unavoidable result of the Critique of Reason and foretold by; it as the Messiah was foretold by John the Baptist. And by the evil fruit we know the evil root: the idealistic theory is philosophical nihilism, for it denies the reality of the external world, as the materialism of Spinoza denies a transcendent G.o.d and the freedom of the will. Reality slips away from both these systems-they are the only consistent ones there are-material reality escaping from the former and suprasensible reality from the latter; and this must be so, because reality, of whatever kind it be, cannot be known, but only believed and felt. The actual, the existence of the noumenal as well as of the external world, even the existence of our own body, makes itself known to us through revelation alone; the understanding comprehends relations only; the certainty that a thing exists is attained only through experience and faith. Sense and reason are the organs of faith, and hence the true sources of knowledge; the former apprehends the natural, the latter, the supernatural, while for the understanding is left only the a.n.a.lysis and combination of given intuitions.
Philosophy as a science from concepts must necessarily prove atheistic and fatalistic. Conception and proof mean deduction from conditions. How shall that which has no cause from which to explain it, the unconditioned, G.o.d, and freedom, be comprehended and proved? Demonstration rises along the chain of causes to the universe alone, not to a transcendent Creator; mediate knowledge is confined to the sphere of conditioned being and mechanical becoming. The intuitive knowledge of feeling alone leads us beyond this, and along with the wonderful, the inconceivable power of freedom in ourselves, which is above all nature, shows us the primal source of all wonders, the transcendent G.o.d above us. The inference from our own spiritual, self-conscious, free personality to that of G.o.d is no unauthorized anthropomorphism-in the knowledge of G.o.d we may fearlessly deify our human existence, because G.o.d, when he created man, gave his divine nature human form. Reason and freedom are the same: the former is theoretical, the latter practical elevation to the suprasensible. Nevertheless virtue is not based upon an inflexible, despotic, abstractly, formal law, but upon an instinct, which, however, does not aim at happiness. Thus Jacobi attempts to mediate between the ethics of the Illumination and the ethics of Kant, by agreeing with the former in regard to the origin of virtue (it arises from a natural impulse), and with the latter in regard to its nature (it consists in disinterestedness). Hence with the Illumination he rejects the imperative form, and with Kant the eudemonistic end. At the same time he endeavors to introduce Herder's idea of individuality into ethics, by demanding that morality a.s.sume a special form in each man. Schiller and the romantic school take from Jacobi their ideal of the "beautiful soul," which from natural impulse realizes in its action, and still more in its being, the good in an individual way.
PART II. FROM KANT TO THE PRESENT TIME.
CHAPTER IX.
KANT.
The suit between empiricism and rationalism had continued for centuries, but still awaited final decision. Are all our ideas the result of experience, or are they (wholly or in part) an original possession of the mind? Are they received from without (by perception), or produced from within (by self-activity)? Is knowledge a product of sensation or of pure thought? All who had thus far taken part in this discussion had resembled partisans or advocates rather than disinterested judges. They had given less attention to investigation than to the defense of the traditional theses of their schools; they had not endeavored to obtain results, but to establish results already determined; and, along with real arguments, popular appeals had not been despised. Each of the opposing schools had given variations on a definite theme, and whenever timid attempts had been made to bring the two melodies into harmony they had met with no approval. The proceedings thus far had at least made it evident to the unbiased hearer that each of the two parties made extravagant claims, and, in the end, fell into self-contradiction. If the claim of empiricism is true, that all our concepts arise from perception, then not only the science of the suprasensible, which it denies, but also the science of the objects of experience, about which it concerns itself, is impossible. For perception informs us concerning single cases merely, it can never comprehend all cases, it yields no necessary and universal truth; but knowledge which is not apodictically valid for every reasoning being and for all cases is not worthy the name. The very reasons which were intended to prove the possibility of knowledge give a direct inference to its impossibility. The empirical philosophy destroys itself, ending with Hume in skepticism and probabilism. Rationalism is overtaken by a different, and yet an a.n.a.logous fate-it breaks up into a popular eclecticism. It believes that it has discovered an infallible criterion of truth in the clearness and distinctness of ideas, and a sure example for philosophical method in the method of mathematics. In both points it is wrong. The criterion of truth is insufficient, for Spinoza and Leibnitz built up their opposing theories-the pantheism of the one and the monadology of the other-from equally clear and distinct conceptions; tried by this standard individualism is just as true as pantheism. Mathematics, again, does not owe its unquestioned acceptance and cogent force to the clearness and distinctness of its conceptions, but to the fact that these are capable of construction in intuition. The distinction between mathematics and metaphysics was overlooked, namely, that mathematical thought can transform its conceptions into intuitions, can generate its objects or sensuously present them, which philosophical thought is not in a position to do. The objects of the latter must be given to it, and to the human mind they are given in no other way than through sensuous intuition. Metaphysics seeks to be a science of the real, but it is impossible to conjure being out of thought; reality cannot be proved from concepts, it can only be felt. In making the unperceivable and suprasensible (the real nature of things, the totality of the world, the Deity, and immortality) the special object of philosophy, rationalism looked on the understanding as a faculty of knowledge by which objects are given. In reality objects can never be given through concepts; these only render it possible to think objects given in some other way (by intuition). It is true that concepts of the suprasensible exist, but nothing can be known through them, there is nothing intuitively given to be subsumed under them.
With this failure to perceive the intuitive element in mathematics was joined the mistake of overlooking its synthetic character. The syllogistic method of presentation employed in the Euclidean geometry led to the belief that the more special theorems had been derived from the simpler ones, and these from the axioms, by a process of conceptual a.n.a.lysis; while the fact is that in mathematics all progress is by intuition alone, the syllogism serving merely to formulate and explain truths already attained, but not to supply new ones. Following the example of mathematics thus misunderstood, the mission of philosophy was made to consist in the development of the truths slumbering in pregnant first principles by means of logical a.n.a.lysis. If only there were metaphysical axioms! If we only did not demand, and were not compelled to demand, of true science that it increase our knowledge, and not merely give an a.n.a.lytical explanation of knowledge. When once the clearness and distinctness of conceptions had been taken in so purely formal a sense, it was inevitable that in the end, as productivity became less, the principle should be weakened down to a mere demand for the explanation and elucidation of the metaphysical ideas present in popular consciousness. Thus the rationalistic current lost itself in the shallow waters of the Illumination, which soon gave as ready a welcome to the empirical theories-since these also were able to legitimate themselves by clear and distinct conceptions-as it had given to the results of the rationalistic systems.
It was thus easy to see that each of the contending parties had been guilty of one-sidedness, and that in order to escape this a certain mean must be a.s.sumed between the two extremes; but it was a much more difficult matter to discover the due middle ground. Neither of the opposing standpoints is so correct as its defenders believe, and neither so false as its opponents maintain. Where, then, on either side, does the mistaken narrowness begin, and how far does the justification of each extend?
The conflict centers, first, about the question concerning the origin of human knowledge and the sphere of its validity. Rationalism is justified when it a.s.serts that some ideas do not come from the senses. If knowledge is to be possible, some concepts cannot originate in perception, those, namely, by which knowledge is const.i.tuted, for if they should, it would lack universality and necessity. The sole organ of universally valid knowledge is reason. Empiricism, on the other hand, is justified when it a.s.serts that the experiential alone is knowable. Whatever is to be knowable must be given as a real in sensuous intuition. The only organ of reality is sensibility. Rationalism judges correctly concerning the origin of the most important cla.s.ses of ideas; empiricism concerning the sphere of their validity. The two may be thus combined: some concepts (those which produce knowledge) take their origin in reason or are a priori, but they are valid for objects of experience alone. The conflict concerns, secondly, the use of the deductive (syllogistic) or the inductive method. Empiricism, through its founder Bacon, had recommended induction in place of the barren syllogistic method, as the only method which would lead to new discoveries. It demands, above all things, the extension of knowledge. Rationalism, on the contrary, held fast to the deductive method, because the syllogism alone, in its view, furnishes knowledge valid for all rational beings. It demands, first of all, universality and necessity in knowledge. Induction has the advantage of increasing knowledge, but it leads only to empirical and comparative, not to strict universality. The syllogism has the advantage of yielding universal and necessary truth, but it can only explicate and establish knowledge, not increase it. May it not be possible so to do justice to the demands of both that the advantages which they seek shall be combined, and the disadvantages which have been feared, avoided? Are there not cognitions which increase our knowledge (are synthetic) without being empirical, which are universally and necessarily valid (a priori) without being a.n.a.lytic? From these considerations arises the main question of the Critique of Pure Reason: How are synthetic judgments a priori possible?
The philosophy of experience had overestimated sense and underestimated the understanding, when it found the source of all knowledge in the faculty of perception and degraded the faculty of thought to an almost wholly inactive recipient of messages coming to it from without. From the standpoint of empiricism concepts (Ideas) deserve confidence only in so far as they can legitimate themselves by their origin in sensations (impressions). It overlooks the active character of all knowing. Among the rationalists, on the other hand, we find an underestimation of the senses and an overestimation of the understanding. They believe that sense reveals only the deceptive exterior of things, while reason gives their true non-sensuous essence. That which the mind perceives of things is deceptive, but that which it thinks concerning them is true. The former power is the faculty of confused, the latter the faculty of distinct knowledge. Sense is the enemy rather than the servant of true knowledge, which consists in the development and explication of pregnant innate conceptions and principles. These philosophers forget that we can never reach reality by conceptual a.n.a.lysis; and that the senses have a far greater importance for knowledge than merely to give it an impulse; that it is they which supply the understanding with real objects, and so with the content of knowledge. Beside the (formal) activity (of the understanding), cognition implies a pa.s.sive factor, a reception of impressions. Neither sense alone nor the understanding alone produces knowledge, but both cognitive powers are necessary, the active and the pa.s.sive, the conceptual and the intuitive. Here the question arises, How do concept and intuition, sensuous and rational knowledge, differ, and what is the basis of their congruence? Notwithstanding their different points of departure and their variant results, the two main tendencies of modern philosophy agree in certain points. If the conflict between the two schools and their one-sidedness suggested the idea of supplementing the conclusions of the one by those of the other, the recognition of the incorrectness of their common convictions furnished the occasion to go beyond them and to establish a new, a higher point of view above them both, as also above the eclecticism which sought to unite the opposing principles. The errors common to both concern, in the first place, the nature of judgment and the difference between sensibility and understanding. Neither side had recognized that the peculiar character of judgment consists in active connection. The rationalists made judgment an active function, it is true, but a mere activity of conscious development, of elucidation and a.n.a.lytical inference, which does not advance knowledge a single step. The empiricists described it as a process of comparison and discrimination, as the mere perception and recognition of the relations and connections already existing between ideas; while in reality judgment does not discover the relations and connections of representations, but itself establishes them. In the former case the synthetic moment is ignored, in the latter the active moment. The imperfect view of judgment was one of the reasons for the appearance of extreme theories concerning the origin of ideas in reason or in perception. Rationalism regards even those concepts which have a content as innate, whereas it is only formal concepts which are so. Empiricism regards all, even the highest formal concepts (the categories), as abstracted from experience, whereas experience furnishes only the content of knowledge, and not the synthesis which is necessary to it. On the one hand too much, and on the other too little, is regarded as the original possession of the understanding. The question "What concepts are innate?" can be decided only by answering the further question, What are the concepts through which the faculty of judgment connects the representations obtained from experience? These connective concepts, these formal instruments of synthesis are a priori. The agreement of the two schools is still greater in regard to the relation of sense and understanding, notwithstanding the apparently sharp contrast between them. The empiricist considers thought transformed, sublimated perception, while the rationalist sees in perception only confused and less distinct thought. For the former concepts are faded images of sensations, for the latter sensations are concepts which have not yet become clear; the difference is scarcely greater than if the one should call ice frozen water, and the other should prefer to call water melted ice. Both arrange intuition and thought in a single series, and derive the one from the other by enhancement or attenuation. Both make the mistake of recognizing only a difference in degree where a difference in kind exists. In such a case only an energetic dualism can afford help. Sense and understanding are not one and the same cognitive power at different stages, but two heterogeneous faculties. Sensation and thought are not different in degree, but in kind. As Descartes began with the metaphysical dualism of extension and thought, so Kant begins with the noetical dualism of intuition and thought.
Much more serious, however, than any of the mistakes yet mentioned was a sin of omission of which the two schools were alike guilty, and the recognition and avoidance of which const.i.tuted in Kant's own eyes the distinctive character of his philosophy and its principiant-advance beyond preceding systems. The pre-Kantian thinker had proceeded to the discussion of knowledge without raising the question of the possibility of knowledge. He had approached things in the full confidence that the human mind was capable of cognizing them, and with a nave trust in the power of reason to possess itself of the truth. His trust was nave and ingenuous, because the idea that it could deceive him had never entered his mind. Now no matter whether this belief in man's capacity for knowledge and in the possibility of knowing things is justifiable or not, and no matter how far it may be justifiable, it was in any case untested; so that when the skeptic approached with his objections the dogmatist was defenseless. All previous philosophy, so far as it had not been skeptical, had been, according to Kant's expression, dogmatic; that is, it had held as an article of faith, and without precedent inquiry, that we possess the power of cognizing objects. It had not asked how this is possible; it had not even asked what knowledge is, what may and must be demanded of it, and by what means our reason is in a position to satisfy such demands. It had left human intelligence and its extent uninvestigated. The skeptic, on the other hand, had been no more thorough. He had doubted and denied man's capacity for knowledge just as uncritically as the dogmatist had believed and presupposed it. He had directed his ingenuity against the theories of dogmatic philosophy, instead of toward the fundamental question of the possibility of knowledge. Human intelligence, which the dogmatist had approached with unreasoned trust and the skeptic with just as unreasoned distrust, is subjected, according to the plan of the critical philosopher, to a searching examination. For this reason Kant termed his standpoint "criticism," and his undertaking a "Critique of Reason." Instead of a.s.serting and denying, he investigates how knowledge arises, of what factors it is composed, and how far it extends. He inquires into the origin and extent of knowledge, into its sources and its limits, into the grounds of its existence and of its legitimacy. The Critique of Reason finds itself confronted by two problems, the second of which cannot be solved until after the solution of the first. The investigation of the sources of knowledge must precede the inquiry into the extent of knowledge. Only after the conditions of knowledge have been established can it be ascertained what objects are attainable by it. Its sphere cannot be determined except from its origin.
Whether the critical philosopher stands nearer to the skeptic or to the dogmatist is rather an idle question. He is specifically distinct from both, in that he summons and guides the reason to self-contemplation, to a methodical examination of its capacity for knowledge. Where the one had blindly trusted and the other suspected and denied, he investigates; they overlook, he raises the question of the possibility of knowledge. The critical problem does not mean, Does a faculty of knowledge exist? but, Of what powers is it composed? are all objects knowable which have been so regarded? Kant does not ask whether, but how and by what means, knowledge is possible. Everyone who gives himself to scientific reflection must postulate that knowledge is possible, and the demand of the noetical theorists of the day for a philosophy absolutely without a.s.sumptions is quite incapable of fulfillment. Nay, in order to be able to begin his inquiry at all, it was necessary for Kant to a.s.sume still more special postulates; for that a cognition of cognition is possible, that there is a critical, self-investigating reason could, at first, be only a matter of belief. This would not have excluded a supplementary detailed statement concerning the how of this self-knowledge, concerning the organ of the critical philosophy. But Kant never gave one, and the omission subsequently led to a sharp debate concerning the character and method of the Critique of Reason. On this point, if we may so express it, Kant remained a dogmatist.
Kant felt himself to be the finisher of skepticism; but this was chiefly because he had received the strongest impulse to the development of his critique of knowledge from Hume's inquiries concerning causation. Brought up in the dogmatic rationalism of the Wolffian school, to which he remained true for a considerable period as a teacher and writer (till about 1760), although at the same time he was inquiring with an independent spirit, Kant was gradually won over through the influence of the English philosophy to the side of empirical skepticism. Then-as the result, no doubt, of reading the Nouveaux Essais of Leibnitz, published in 1765-he returned to rationalistic principles, until finally, after a renewal of empirical influences,[1] he took the position crystallized in the Critique of Pure Reason, 1781, which, however, experienced still other, though less considerable, changes in the sequel, just as in itself it shows the traces of previous transformations.
[Footnote 1: Cf. H. Vaihinger's Kommentar zu Kants Kritik der reinen Vernunft, vol. i., 1881, pp. 48-49. This is a work marked by acuteness, great industry, and an objective point of view which merits respect. The second volume, which treats of the Transcendental Aesthetic, appeared in 1892.]
It would be a most interesting task to trace in the writings which belong to Kant's pre-critical period the growth and development of the fundamental critical positions. Here, however, we can only mention in pa.s.sing the subjects of his reflection and some of the most striking antic.i.p.ations and beginnings of his epoch-making position. Even his maiden work, Thoughts on the True Estimation of Vis Viva, 1747, betokens the mediating nature of its author. In this it is argued that when men of profound and penetrating minds maintain exactly opposite opinions, attention must be chiefly directed to some intermediate principle to a certain degree compatible with the correctness of both parties. The question under discussion was whether the measure of vis viva is equal, as the Cartesians thought, to the product of the ma.s.s into the velocity, or, according to the Leibnitzians, to the product of the ma.s.s into the square of the velocity. Kant's unsatisfactory solution of the problem-the law of Descartes holds for dead, and that of Leibnitz for living forces-drew upon him the derision of Lessing, who said that he had endeavored to estimate living forces without having tested his own. A similar tendency toward compromise-this time it is a synthesis of Leibnitz and Newton-is seen in his Habilitationsschrift, Principiorum Primorum Cognitionis Metaphysicae Nova Dilucidatio, 1755, and in the dissertation Monadologia Physica, 1756. The former distinguishes between ratio essendi and ratio cognoscendi, rejects the ontological argument, and defends determinism against Crusius on Leibnitzian grounds. In the Physical Monadology Kant gives his adherence to dynamism (matter the product of attraction and repulsion), and makes the monads or elements of body fill s.p.a.ce without prejudice to their simplicity. A series of treatises is devoted to subjects in natural science: The Effect of the Tides in r.e.t.a.r.ding the Earth's Rotation; The Obsolescence of the Earth; Fire (Inaugural Dissertation), Earthquakes, and the Theory of the Winds. The most important of these, the General Natural History and Theory of the Heavens, 1755, which for a long time remained unnoticed, and which was dedicated to Frederick II., developed the hypothesis (carried out forty years later by Laplace in ignorance of Kant's work) of the mechanical origin of the universe and of the motion of the planets. It presupposes merely the two forces of matter, attraction and repulsion, and its primitive chaotic condition, a world-mist with elements of different density. It is noticeable that Kant acknowledges the failure of the mechanical theory at two points: it is brought to a halt at the origin of the organic world and at the origin of matter. The mechanical cosmogony is far from denying creation; on the contrary, the proof that this well-ordered and purposive world necessarily arose from the regular action of material forces under law and without divine intervention, can only serve to support our a.s.sumption of a Supreme Intelligence as the author of matter and its laws; the belief is necessary, just because nature, even in its chaotic condition, can act only in an orderly and regular way.
The empirical phase of Kant's development is represented by the writings of the 60's. The False Subtlety of the Four Syllogistic Figures, 1762, a.s.serts that the first figure is the only natural one, and that the others are superfluous and need reduction to the first. In the Only Possible Foundation for a Demonstration of the Existence of G.o.d, 1763, which, in the seventh Reflection of the Second Division, recapitulates the cosmogony advanced in the Natural History of the Heavens, the discussions concerning being ("existence" is absolute position, not a predicate which increases the sum of the qualities but is posited in a merely relative way), and the conclusion, prophetical of his later point of view, "It is altogether necessary that we should be convinced of the existence of G.o.d, but not so necessary that his existence should be demonstrated" are more noteworthy than the argument itself. This runs: All possibility presupposes something actual wherein and whereby all that is conceivable is given as a determination or a consequence. That actuality the destruction of which would destroy all possibility is absolutely necessary. Therefore there exists an absolutely necessary Being as the ultimate real ground of all possibility; this Being is one, simple, unchangeable, eternal, the ens realissimum and a spirit. The Attempt to introduce the Notion of Negative Quant.i.ties into Philosophy, 1763, distinguishes-contrary to Crusius-between logical opposition, contradiction or mere negation (a and not-a, pleasure and the absence of pleasure, power and lack of power), and real opposition, which cannot be explained by logic (+a and -a, pleasure and pain, capital and debts, attraction and repulsion; in real opposition both determinations are positive, but in opposite directions). Parallel with this it distinguishes, also, between logical ground and real ground. The prize essay, Inquiry concerning the Clearness (Evidence) of the Principles of Natural Theology and Ethics, 1764, draws a sharp distinction between mathematical and metaphysical knowledge, and warns philosophy against the hurtful imitation of the geometrical method, in place of which it should rather take as an example the method which Newton introduced into natural science. Quant.i.ty const.i.tutes the object of mathematics, qualities, the object of philosophy; the former is easy and simple, the latter difficult and complicated-how much more comprehensible the conception of a trillion is than the philosophical idea of freedom, which the philosophers thus far have been unable to make intelligible. In mathematics the general is considered under symbols in concrete, in philosophy, by means of symbols in abstracto; the former constructs its object in sensuous intuition, while the object of the latter is given to it, and that as a confused concept to be decomposed. Mathematics, therefore, may well begin with definitions, since the conception which is to be explained is first brought into being through the definition, while philosophy must begin by seeking her conceptions. In the former the definition is first in order, and in the latter almost always last; in the one case the method is synthetic, in the other it is a.n.a.lytic. It is the function of mathematics to connect and compare clear and certain concepts of quant.i.ty in order to draw conclusions from them; the function of philosophy is to a.n.a.lyze concepts given in a confused state, and to make them detailed and definite. Philosophy has also this disadvantage, that it possesses very many undecomposable concepts and undemonstrable propositions, while mathematics has only a few such. "Philosophical truths are like meteors, whose brightness gives no a.s.surance of their permanence. They vanish, but mathematics remains. Metaphysics is without doubt the most difficult of all human sciences (Einsichten), but a metaphysic has never yet been written"; for one cannot be so kind as to "apply the term philosophy to all that is contained in the books which bear this t.i.tle." In the closing paragraphs, on the ultimate bases of ethics, the stern features of the categorical imperative are already seen, veiled by the English theory of moral sense, while the attractive Observations on the Feeling of the Beautiful and the Sublime, which appeared in the same year, still navely follow the empirical road.
The empirical phase reaches its skeptical termination in the satire Dreams of a Ghost-seer explained by the Dreams of Metaphysics, 1766, which pours out its ingenious sarcasm impartially on spiritualism and on the a.s.sumed knowledge of the suprasensible. Here Kant is already clearly conscious of his new problem, a theory of the limits of human reason, conscious also that the attack on this problem is to be begun by a discussion of the question of s.p.a.ce. This second question had been for many years a frequent subject of his reflections;[1] and it was this part of the general critical problem that first received definitive solution. In the Latin dissertation On the Form and Principles of the Sensible and Intelligible World, 1770, which concludes the pre-critical period, and which was written on the occasion of his a.s.sumption of his chair as ordinary professor, the critique of sensibility, the new theory of s.p.a.ce and time, is set forth in approximately the same form as in the Critique of Pure Reason, while the critique of the understanding and of reason, the theory of the categories and the Ideas and of the sphere of their validity, required for its completion the intellectual labor of several more years. For this essay, De Mundi Sensibilis atque Intelligibilis Forma et Principiis, leaves unchallenged the possibility of a knowledge of things in themselves and of G.o.d, thus showing that its author has abandoned the skepticism maintained in the Dreams of a Ghost-seer, and has turned anew to dogmatic rationalism, whose final overthrow required another swing in the direction of skeptical empiricism. In regard to the progress of this latter phase of opinion, the letters to M. Herz are almost the only, though not very valuable, source of information.
[Footnote 1: New Theory of Motion and Rest, 1758; On the First Ground of the Distinction of Positions in s.p.a.ce, 1768; besides several of the works mentioned above.]
The Critique of Pure Reason appeared in 1781, much later than Kant had hoped when he began a work on "The Limits of Sensibility and Reason," and a second, altered edition in 1787.[1] After the Prolegomena to every Future Metaphysic which may present itself as Science, 1783, had given a popular form to the critical doctrine of knowledge, it was followed by the critical philosophy of ethics in the Foundation of the Metaphysics of Ethics, 1785, and the Critique of Practical Reason, 1788; by the critical aesthetics and teleology in the Critique of Judgment, 1790; and by the critical philosophy of religion in Religion within the Limits of Reason Only, 1793[2] (consisting of four essays, of which the first, "Of Radical Evil," had already appeared in the Berliner Monatsschrift in 1792). The Metaphysical Elements of Natural Science, 1786, and the Metaphysics of Ethics, 1797 (in two parts, "Metaphysical Elements of the Theory of Right," and "Metaphysical Elements of the Theory of Virtue "), are devoted to the development of the system. The year 1798 brought two more larger works, the Conflict of the Faculties and the Anthropology. Of the reviews, that on Herder's Ideen maybe mentioned, and among the minor essays, the following: Idea for a Universal History in a Cosmopolitan Sense, Answer to the Question: What is Illumination f both in 1784; What does it mean to Orient oneself in Thought? 1786; On the Use of Teleological Principles in Philosophy, 1788; On a Discovery according to which all Recent Criticism of Pure Reason is to be superseded by a Previous One, 1790; On the Progress of Metaphysics since the Time of Wolff; On Philosophy in General, The End of all Things, 1794; On Everlasting Peace, 1795. Kant's Logic was published by Jasche in 1800; his Physical Geography and his Observations on Pedagogics by F.T. Rink in 1803; his lectures on the Philosophical Theory of Religion (1817; 2d. ed., 1830) and on Metaphysics (1821; cf. Benno Erdmann in the Philosophische Monatshefte, vol. xix. 1883, p. 129 seq., and vol. xx. 1884, p. 65 seq.) by Politz. If we may judge by the specimens given by Reicke in the Altpreussische Monatsschrift, 1882-84, and by Krause himself,[3] the promised publication of a ma.n.u.script of Kant's last years, now in possession of the Hamburg pastor, Albrecht Krause, and which discusses the transition from the metaphysical elements of natural science to physics, will hardly meet the expectations which some have cherished concerning it. Benno Erdmann has issued Nachtrage zu Kants Kritik der reinen Vernunft aus Kants Nachla.s.s, 1881, and Reflexionen Kants zur kritischen Philosophie aus handschriftlichen Aufzeichnungen-the first volume first Heft (Reflexionen zur Anthropologie) appearing in 1882, the second volume (Reflexionen zur Kritik der reinen Vernunft, aus Kants Handexemplar von Baumgartens Metaphysica) in 1884. Max Muller has made an English translation of the Critique of Pure Reason, 2 vols., 1881.[4]
[Footnote 1: There has been much discussion and much has been written concerning the relation of the two editions. In opposition to Schopenhauer and Kuno Fischer it must be maintained that the alterations in the second edition consist in giving greater prominence to realistic elements, which in the first edition remained in the background, though present even there.]
[Footnote 2: This publication was the occasion of a conflict between Kant and the censors.h.i.+p concerning the right of free religious inquiry; cf. Dilthey in the Archiv fur Geschichte der Philosophie, vol. in. 1890, pp. 418-450.]
[Footnote 3: A. Krause: I. Kant wider K. Fischer, zum ersten Male mit Hulfe des verloren gewesenen Kantischen Hauptwerkes vertheidigt, 1884 (in reply, K. Fischer, Das Streber- und Grunderthum in der Litteratur, 1884); also, Das nachgela.s.sene Werk I. Kants, mit Belegen popular-wissenschaftlich dargestellt, 1888.]
[Footnote 4: Besides this (centenary) translation the English reader may be referred to the earlier version of Meiklejohn in Bonn's Library; to the versions of the Prolegomena by Bax (also in Bonn's Library, and including the Metaphysical Elements of Natural Science), and Mahaffy and Bernard, new ed., 1889; to Abbot's Kant's Theory of Ethics, 4th ed., 1889, containing the Foundation of the Metaphysics of Ethics and the Critique of Practical Reason entire, with portions of the Metaphysics of Ethics and Religion within the Limits of Reason Only; to Bernard's translation of the Kritik of Judgment, 1892; and to Watson's Selections from Kant, 2d ed., 1888 (in Sneath's Modern Philosophers, 1892).-TR.]
The best complete edition of the works of Kant is the second edition of Hartenstein, in eight volumes, 1867-68, which is chronologically arranged and excellently gotten up. Simultaneously with the first edition of Hartenstein in ten volumes, in 1838 seq., appeared the edition in twelve volumes by K. Rosenkranz and F.W. Schubert (containing in the last volumes a biography of Kant by Schubert, and a history of the Kantian philosophy by Rosenkranz, 1842). Kehrbach's edition of the princ.i.p.al works in Reclam's Universal-Bibliothek, with the pagination of the original and collective editions (1877 seq.), is more valuable than Von Kirchmann's edition of the complete works in his Philosophische Bibliothek.
Among the works on Kant those of Kuno Fischer (vols. iii.-iv. of the Geschichte der neueren Philosophie, 3d ed., 1882; also Kant's Leben und die Grundlagen seiner Lehre, 1860) take the first place. The writings of Liebmann, Cohen, Stadler, Riehl, Volkelt, and others will be mentioned later, in connection with the neo-Kantian movement; here we may give some of the more important monographs and essays, selected from the enormously developed Kantian literature:
Ad. Bohringer, Kants erkenntnisstheoretischer Idealismus, 1888; K. Dieterich, Die Kantische Philosophie in ihrer inneren Entwickelungsgeschichte, 2 parts, 1885 (first published separately, Kant und Newton, 1877; Kant und Rousseau, 1878); W. Dilthey, Aus den Rostocker Kanthandschriften in the Archiv fur Geschichte der Philosophie, vols. ii.-iii. 1889-90; M.W. Drobisch, Kants Ding an sich und sein Erfahrungsbegriff, 1885; B. Erdmann, Kants Kritizismus in der I. und II. Auflage der Kritik der reinen Vernunft, 1878; the same, Kants Prolegomena herausgegeben und erlautert, 1878, Introduction (in reply Emil Arnoldt, Kants Prolegomena nicht doppelt redigiert, 1879; cf. also H. Vaihinger, Die Erdmann-Arnoldtsche Kontroverse in the Philosophische Monatshefte, vol. xvi. 1880); Franz Erhardt, Kritik der Kantischen Antinomienlehre, 1888; R. Eucken, Ueber Bilder und Gleichnisse bei Kant, Zeitschrift fur Philosophie, vol. lx.x.xiii, 1883, reprinted in his Beitrage zur Geschichte der neueren Philosophie, 1886; F. Frederichs, Der phanomenale Idealismus Berkeleys und Kants, 1871; the same, Kants Prinzip der Ethik, 1879; Ed. von Hartmann, Das Ding an sich und seine Beschaffenheit, 1871, in the 2d ed., 1875, and the 3d, 1885, ent.i.tled Kritische Grundlegung des transzendentalen Realismus; C. Hebler, Kantiana, in his Philosophische Aufsatze, 1869; Alfred Hegler, Die Psychologie in Kants Ethik, 1891; A. Holder, Darstellung der Kantischen Erkenntnisstheorie, 1873 J. Jacobson, Die Auffindung des Apriori, 1876; the same, Ueber die Beziehungen zwischen Kategorien und Urtheilsformen, 1877; Wilhelm Koppelmann, Kants Lehre vom a.n.a.lytischen Urtheil, Philosoph. Monatshefte, vol. xxi, 1885; the same, Lotzes Stellung zu Kants Kritizismus, Zeitschrift fur Philosophie, vol. lx.x.xviii, 1886; the same, Kants Lehre vom kategorischen Imperativ, 1888; the same, Kant und die Grundlagen der Christlichen Religion, 1890; E. Laas, Kants a.n.a.logien der Erfahrung, 1876; the same, Einige Bemerkungen zur Transzendentalphilosophie, Stra.s.sburg Abhandlungen, 1884; J. Mainzer, Die kritische Epoche in der Lehre von der Einbildungskraft, 1881; J.B. Meyer, Kants Psychologie, 1870; F. Paulsen, Was Kant uns sein kann, Vierteljahrsschrift fur wissenschaftliche Philosophie, 1881; B. Punjer, Die Religionslehre Kants, 1874; R. Quaebicker, Kants und Herbarts metaphysische Grundansichten uber das Wesen der Seele, 1870; J. Rehmke, Physiologie und Kantianismus, address in Eisenach, 1883; Rud. Reicke, Lose Blatter aus Kants Nachla.s.s, 1889 (on this H. Vaihinger in the Zeitschrift fur Philosophie, vol. xcvi. 1889); O. Riedel, Die monadologischen Bestimmungen in Kants Lehre vom Ding an sich, dissertation at Kiel, 1884; O. Schneider, Die psychologische Entwickelung des Apriori, 1883; the same, Transzendentalpsychologie, 1891; F. Staudinger, Noumena, 1884; M. Steckelmacher, Die formale Logik Kants, Breslau Prize Essay, 1879; A. Stern, Die Beziehung Garves zu Kant, nebst ungedruckten Briefen, 1884; C. Stumpf, Psychologie und Erkenntnisstheorie, Abhandlungen der bayerischen Akademie der Wissenschaften, 1891; G. Thiele, Kants intellectuelle Anschauung als Grundbegriff seines Kritizismus, 1876; the same, Die Philosophie Kants nach ihrem systematischen Zusammenhange und ihrer logischhistorischen Entiwickelung, I. (1) Kants vorkritische Naturphilosophie, 1882; (2) Kants vorkritische Erkenntnisstheorie, 1887; Ad. Trendelenburg, Ueber eine Lucke in Kants Beweis von der ausschliessenden Subjectivitat des Raumes and der Zeit in vol. iii. of his Historische Beitrage zur Philosophie, 1867; Ueberhorst, Kants Lehre von dem Verhaltnisse der Kategorien zu der Erfahrung, 1878; H. Vaihinger, Eine Blattversetzung in Kants Prolegomena, Philosoph. Monatshefte, vol. xv. 1879; the same, Zu Kants Widerlegung des Idealismus, Stra.s.sburg Abhandlungen, 1884; J. Walter, Zum Gedachtniss Kants, Festrede, 1881; Th. Weber, Zur Kritik der Kantischen Erkenntnisstheorie (from the Zeitschrift fur Philosophie), 1882; W. Windelband, Ueber die verschiedenen Phasen der Kantischen Lehre vom Ding an sich, Vierteljahrsschrift fur wissenschaftliche Philosophie, 1877 (cf. the same author's Geschichte der neueren Philosophie, -- 58); J. Witte, Beitrage zum Verstandniss Kants, 1874; the same, Kantischer Kritizismus gegenuber unkritischem Dilettantismus (against A. Stohr), 1885; Wohlrabe, Kants Lehre vom Gewissen, 1889; E. Zeller, Ueber das Kantische Moralprinzip, 1880; R. Zimmermann, Ueber Kants Widerlegung des Idealismus von Berkeley, 1871; the same, Ueber Kants mathematisches Vorurtheil und dessen Folgen, 1871.
Popular expositions have been given by the following: K. Fortlage (in his Philos. Vortrage, 1869); E. Last, Mehr Licht! Die Haupsatze Kants und Schopenhauers, 1879; the same, Die realistiche und die idealistische Anschauung entwickelt an Kants Idealitat von Raum und Zeit, 1884; H. Romundt, Antaeus, neuer Aufbau der Lehre Kants uber Seele, Freiheit, und Gott, 1882; the same, Grundlegung zur Reform der Philosophie, vereinfachte und erweiterte Darstellung von Kants Kritik der reinen Vernunft, 1885; the same, Die Vollendung des Socrates, Kants Grundlegung zur Reform der Sittenlehre; the same, Ein neuer Paulus, Kants Grundlegung zu einer sicheren Lehre von der Religion, 1886; the same, Die drei Fragen Kants, 1887; A. Krause, Populare Darstellung von Kants Kritik der reinen Vernunft, 1881; K. La.s.switz, Die Lehre Kants von der Idealitat des Raumes und der Zeit, 1883; Wilhelm Munz, Die Grundlagen der Kantischen Erkenntnisstheorie, 2d ed., 1885.
Among foreigners Villers, Cousin, Nolen, Desdouits, Cantoni, E. Caird [A Critical Account of the Philosophy of Kant, 1877; The Critical Philosophy of Immanuel Kant, 2 vols., 1889], Adamson [On the Philosophy of Kant, 1879, and a valuable article in the Encyclopedia Britannica, 9th ed., vol. xiii