The necessary revolution in man's thinking after Immanuel Kant

intuitional synthesis, and this second one he calls the ‘intellectual synthesis’. In the first the sense stimuli are given symbolic form in the mind, becoming a spatio-temporal image; in the second, what has resulted from the first process comes to have explicit, rational content; it becomes conscious of itself and takes on the form of an experience. The final product of this two-phase process is our actual experience, or what Kant calls ‘phenomenon’. The German, die Erscheinung, means what appears to a human being.

On the lines I have been indicating, Kant rigorously fixed the limits of any possible human knowledge. Human thought, he says, cannot legitimately go outside the realm of phenomena, that is, of experience manifested through the synthesis of an intuition based on the senses with a category that reveals its rational meaning. In other words, we human beings can exercise our cognitive faculties only in the world in which an intuition is possible, that is to say, in the world which has originated through the senses. Every attempt of thought to escape outside the limits of this domain Kant declared to be arbitrary and unjustifiable.

These categories, through which the intellectual synthesis is effected, are transcendental in the same way as the two a priori forms, space and time. According to Kant, these categories must not be understood as forming part of the subject, nor as structures of reality-in-itself, both these being unknowable; nor are they, like Plato’s ideas, entities, not even purely conceptual entities. We must recognise them to be forms through which the experience or phenomenon acquires consistence, forms that are therefore strictly bound up with experience and constitute its rational structure, apart from which they cannot in any sense exist. The experience or phenomenon, on the other hand, is the world itself, as it appears to us human beings; and for this reason we can say that the system of categories has its place in this world of experience as the logical structure which upholds it. On this fact Kant bases his conclusion concerning the validity of the sciences. The natural sciences, he says, have as their foundation the system of categories just as the sciences of geometry and mathematics have as their foundation the a priori forms, space and time. Both of these foundations are impregnable to the attacks of sceptical

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