In the meantime the empiricism begun by Bacon and the rationalism begun by Deseartes became curiously intermixed in Locke's theory of knowledge. Locke supported the Baconian appeal to experience. The sole sources of our knowledge are empirical facts, since the mind has no innate ideas. All the materials of knowl edge are externally impressed upon the mind. the sole activity of which consists in linking together the given ideas. Upon this sensationalistic basis, however. Locke built up a rationalistic ideal of knowledge. We attain certainty in our intuitive knowledge of the existence of the self, and in the demonstrative knowledge of the existence of God, and of mathematical and moral truths as well. Our knowledge of the external world, being dependent upon sense-perception, reaches only the level of probability. In this. Locke violated his 01‘1.1 fundamental principle that our knowledge extends no further than our sensa tionally given ideas, and that truth consists in the agreement of ideas among themselves, not in their correspondence with things or external reality. Berkeley took Locke's definition of knowledge in a strict sense, and insisted that we never get beyond the circle of our own ideas. We know nothing about the agreement of our subjective ideas with external things. All knowl edge. lie contended, is purely individual, and all ideas are merely particular. The mistaken belief in the existence of self is due to the confusion of taking an abstract or general name as repre sentative of a real thing. The reality of sense objects consists in their being perceived. The assumption of an object apart from the idea is as useless as its existence would be. Ideas signify nothing but modifications of the conscious subject. Hume carried empiricism to its inevitable logical consequence. There is nothing knowable, he ar gued. but conscious experiences—'impressions' and their copies, 'ideas.' These we cannot transcend. They are externilly connected by `gentle forces.' called relations or associations. We cannot prove the existence of God, of the self. or of matter. All these are fictions of the imagination, and have no basis in actual experi ence. Thus, step by step, empiricism ends in skepticism.
Kant, the founder of the critical philosophy, consciously and critically attempted what Locke had naïvely achieved, the arbitration of the controversy between empiricism and rationalism. His decision was that rationalism is right in its determination of scientific method: empiricism, in limiting scientific knowledge to the sphere of possible experience or phenomena. Knowledge, he maintained, is a joint product of two factor?, one furnished by the conscious subject, the other given in the raw material of sensation. The former is a priori: it antedates experience and is the condition which makes experience possible. The latter is a posteriori, given from without. The a priori would be devoid of content without the sensible material; the a posteriori would be nothing at all were it not shaped and trans figured in the mold of consciousness. Theoretical reason may not transcend the bounded domain of experience, but practical reason asserts the necessity of the belief in a world of transcendent reality, in which the moral order is the natural law. God, freedom. and iim»ortality. though undemonstrable. are the necessary postulates of our moral being. Thus reason gives way to
faith. Fichte, starting from a Kantian basis, objected to Kant's failure to show how the priori principles of consciousness are necessarily involved in the nature of consciousness, as well ' as to the Kantian separation of the phenomenal world and the real world of things-in-themselves. By exhibiting the process in which consciousness unfolds itself, we see that the phenomenal world is meaningless unless organically connected with its intelligible essence. Knowledge is neither in whole (Hume) nor in part (Kant) the product of sensation. It is the creation of the ego. Voluntary selves freely choose to assert them selves and thus construct their whole organized world. The moral law is the prior condition of all we theoretically know. and the outer world exists simply for the sake of our moral self realization. The speculative method, the exhibi tion of the progressive nature of consciousness, is the only possible method, since knowing does not begin with facts passively received by the ego. but with a spontaneous act of the ego', creative energy. Jacobi also objected to the Kantian separation between the thing-in-itself and the phenomenal world. Without the thing in-itself, he said, no one can enter the Kantian system, and with it no one can remain in that system. The only solution of this antinomy was to exalt faith. to which even Kant had recourse. to the supreme place in philosophy. Not knowl edge. but feeling, is the organon whereby we can attain certainty of reality. Thus results a philosophy of supranatural sensualism. Schell ing reached much the same result, but by a different method. He regarded the world as the embodiment of intelligence, an objective fact. indeed. but one that exhibits in its progressive forms the same principle that is found in mon. But the character of that absolute principle which thus manifests itself in external nature and in man cannot be apprehended by reason. Intuition alone brings us into contact with ulti mate reality. In Hegel German rationalism vigorously reasserted itself: the real is the ra tional and the rational is the real. All reality is but a manifestation of reason. The world is a development of thought. But thought and reason are not abstractions. The word thought is used with a width of meaning that includes in it the concrete content of the world of sense organized into an all-inclusive universe. The life and stir of the universe is the life of thought. The development of this concrete thought is a dialectical development, hence philosophy must employ the dialectical method to exhibit the nature of reality. The motive force of this development is opposition and negation. Every thine is what it is by virtue of what it is net that is. by virtue of its relation to other things. These various things taken apart are self-con tradictory; only when seen in their interconnec tion are they seen to be real. The contradictories are not annulled in their mutual relations; they :ire conserved. but thus conserved no longer are they contradictory. The tracing of this process of negation is the Hegelian dialectic. With the death of Hegel, Hegelianism broke up into war ring schools and became utterly discounted in Germany. only to be resuscitated later in England and America in the so-called Neo-1 Iegelian School.