FROM KANT TO HEGEL Kant ( 1724-1804) is the founder of the "critical" philosophy or of "transcendentalism." The stress which Descartes had laid on thought, or subjective experience, in basing his whole system on the cogito ergo sum, quite naturally resulted in a divorce be- ' tween ideas, on the one hand, and the external world on the other. This is clear alike in the idealism of Leibniz and Berkeley, in the empiricism of Locke, and in the scepticism of Hume. The only philosophers of importance who avoided this predicament were Spinoza, on the one hand, and Thomas Reid (1710-96) and the Scottish school, on the other. But the alleged atheism of Spinoza robbed him of real influence ; and the "common-sense philosophy" of the Scottish school was not sufficiently subtle to impress speculative minds. Kant attempted a new way of bring ing thought and reality into touch once more. Kant himself liked to stress the "critical" character of his philosophy as the new element which he contributed; and consequently called his three great works critiques. He described all his predecessors as "dogmatic" philosophers, because they did not begin their philos ophy with a critical examination of human capacity for knowl edge.
The way in which Kant attempted to reunite knowledge with reality was briefly as follows. Known objects, according to Kant, are a multiplicity of sense-materials supplied to the apprehend ing mind which synthesizes them in accordance with certain forms of intuition (space and time) and certain categories of thought (substance and attribute, cause and effect, etc.). What the multi plicity of sense-materials may be before the mind has synthesized them, we do not and cannot know. But they are not produced by the mind, they are only apprehended and moulded by it—they are or pertain to "things-in-themselves." On the other hand, the forms of intuition and the categories of thought are ways in which the mind in virtue of its own nature moulds or systematizes the multiplicity of disconnected sense-materials so as to adapt them to its own unity. These forms are a priori or "transcen dental" in the sense that they are not derived from experience, inasmuch as experience itself would be impossible without them; on the other hand, the multiplicity of sense-material is a poster iori, only given in experience and known through it (though not known "in itself").
These various a priori forms of apprehension are not peculiari ties of the unity of individual minds as such, but rather express the unity of "consciousness in general" in which individual minds participate, but which is "super-individual." That is how it comes about that there is universal agreement in the use of the a priori forms and categories, instead of individual variations. Anyway, human knowledge does not extend to the intrinsic na ture of ultimate reality or "things-in-themselves" but only to their appearances as moulded by the forms of intuition and cate gories of thought. In Kant's language, human knowledge is of "phenomena" not of "noumena" or "things-in-themselves." And any attempt to apply the a priori or "transcendental" forms to what does not fall within the realm of possible human experience, Kant condemned as "transcendent." The existence of God, and the immortality of the soul, e.g., are beyond the realm of possi ble human experience, and therefore of knowledge though what cannot be known may yet be believed as a matter of faith.
And it is on such "practical reasons" that Kant based the beliefs in the existence of God, in the freedom of the will, and in the immortality of the soul. These things, according to Kant, are postulates of morality. The "categorical imperative," the un conditional character of the sense of duty, can only be under stood and justified on the assumption or faith that we are free to do, or "can" do, what we "ought" to do, that there is a God who can duly correlate virtue with happiness, and that there is a hereafter in which the injustices of the present life may be adjusted. Kant's moral philosophy brings out with special clear ness a striking feature of his whole method of philosophizing. He does not doubt the validity of the sense of duty or the "categorical imperative"; he acknowledged it, and only draws out its implica tions or conditions. Similarly, Kant did not question the reality of the external world as conceived by contemporary (Newtonian) science; he accepted it (as Hume the sceptic would not), and tried to elicit the conditions of the validity of that science. (See