CRITIQUE OF PURE REASON, The. Kant's (Critique of Pure Reason' (Kritik der reinen Vernunft) has commanded the at tention of professional philosophers• to an ex tent attained by no other modern work. Though a clumsy, unintelligible and technical writer, Kant long stood at the centre of aca demical philosophy—a position which he still enjoys in Germany—and this Critique is the portal to his system.
In the background are certain moral and re ligious problems of God, Freedom and Immor tality to which the 'Critique is a destructive metaphysical prolegomenon. He is here examin ing into the possibilities of metaphysical knowl edge by a criticism of the nature of knowledge in general and would show through this criti cism that the ideas of a soul, an ordered uni verse and God can have no metaphysical foun dation and are not subject to either metaphysi cal proof or refutation. Their place as objects of belief and their development as moral pos tulates were accordingly made secure. The ob jects of these ideas of soul, cosmos and God are not given us in experience; and the proof of their existence, if it is to be found, must be by way of some knowledge transcending ex perience; so his quest is to find how knowledge a priori is possible.
Kant introduced what he called the Coper nican revolution in philosophy. Philosophy had conceived the mind as that which is impressed with the form of objects and the order of na ture. Kant reversed the point of view, making the mind supply form to its perceptions and structure to its universe. His peculiar contribu tion to epistemology lies in this recognition of the mind as active in experience.
cording to' its own ideas ; so that, although the object is the occasion for the experience, the mind must reproduce this in knowledge and supply the form which it here takes. Experi ence, considered from the point of view of the object, is a chaos of particulars. In so far as it has unity this must be supplied by the mind. As a compound, experience can never give uni versality and necessity. If we find universality and necessity in knowledge, it must come a priori.
There are three stages in knowledge; per ception, judgment and reason. We get experi ence through sense perception; we think these various perceptions under conceptions, that is, make judgments about them, and finally we tie all our experience together under the "ideas' of a simple soul, an ordered and absolute uni verse and a first cause.
The mind perceives the manifold of sense under the forms of time and space. These are known through a priori intuitions for of them we may have universal and necessary proposi tions, such as those of geometry, which could not be arrived at through a summation of par ticulars. They supply unity to the internal and external sense respectively. Space and time have accordingly "transcendental ideality,' i.e., considered as to their origin in the act of know ing, they are ideal, being supplied by the mind.
The matter of perception is the sensation without form. The object, as perceived, is a phenomenon, but behind the phenomenon is something occasioning its being perceived. Al though this thing itself, or "noumenon," must remain unknown to us, for our minds can not reproduce it except according to their own conditions, it is not to be looked on as a mere dialectical by-product, for Kant needed the con ception of noumenon in his moral philosophy.
The second part of the takes up the question of the synthesis of the understand ing. The act of judgment, A is B, is a syn thesis. B may be thought of as a part of, a cause of, or a quality of A, etc. These various relations in which experience is thought, such as whole and part, cause and effect, substance and attribute, are the °categories" or forms of synthesis of the understanding. Kant deduced them from •the classification of propositions given in formal logic. Their significance lies in the conception which they give of knowl edge as a structure, constituted by the mind, and not an accumulation, as, for example, the general conception of universal causal relation among phenomena, is a result of the mind im posing its own law of unity on the manifold, and thus constituting an organized world. The application of these laws of the understanding, however, is only to the world of phenomena be yond which their reign does not extend.
Reason cannot remain satisfied with the manifold given by the understanding in thought and must think this under absolute and uncon ditioned forms which it supplies in the "ideas": "the unity of the thinking "the abso lute unity of the series of the conditions of phenomenap• "the absolute unity of the condi tion of all objects of thought in general," or, in other words, the simple soul, the cosmos and God. The objects of these ideas of pure rea son cannot be presented in possible experience and we can only possess a *problematical con ception' of them. We are led to these ideas by a "necessary procedure of reason," but the at tempts of the orthodox metaphysics to estab lish their objective reality are shown to be il logical and contradictory, thought here running out into certain antinomies. These ideas ex press the utmost possibility of synthesis, the vanishing points in the perspective of human experience. As such they are of use in experi ence, but not for gaining knowledge of the na ture of reality through reason pure and simple.
The influence of the in the history of philosophy has been multiform and is to-day a factor to be reckoned with. The limitation of our knowledge to phenomena comes down in the French positivists and Herbert Spencer; for German idealism the laws of the under standing become the most important features in the structure of reality; and further conse quences by way of Kantian ethics are, perhaps, even more far-reaching.
There are two English translations of the of Pure Reason): one by Max Muller (2d ed., London 1896), and the other J. M. D. Meiklejohn (London 1854 and re prints). The former is much the better. The great commentary in English is E. Caird's Critical Philosophy of (2 vols., London 1889). Four representative German interpre tations are those of Kuno Fischer, H. Vaihin ger, Erich Adickes and Cohen.
WALTETt B. VF.AZIE, Department of Philosophy, Columbia Univer sity.