6. Arthur Schopenhauer

Kant endeavored to seek out the conditions under which the human striving for knowledge can arrive at truths of unconditional and necessary certainty. The Leibniz-Wolffian philosophy, of which Kant was a follower until his in-depth study of Hume's writings, believed that such truths could be spun out of pure reason through purely conceptual thinking. It contrasted these pure rational truths with the knowledge of experience gained through observation of the outer life of nature and the inner life of the soul. According to this view, the latter are not made up of clear, transparent concepts, but of confused and dark ideas. Therefore, this philosophical way of thinking wanted to develop the most valuable insights into the deeper connection of natural events, the nature of the soul and the existence of God from pure concepts of reason. Kant professed these views until he was completely shaken in his convictions by Hume's remarks on the concepts of cause and effect. Hume (1711 to 1776) sought to prove that we can never gain insight into the connection between cause and effect through mere reason. According to Hume, the concept of causation comes from experience. We perceive the emergence of fire and then the heating of the air surrounding it. We have observed the same sequence of these perceptions countless times. We get used to it and assume that we will always observe the same thing as soon as the same conditions are met. But we can never gain an objective certainty about this, for it is impossible to see with the help of mere concepts that something must necessarily follow because something else precedes it. Experience only tells us that up to a certain point in time a certain event has always resulted in a certain other event, but not that the one must result in the other, i.e. that it will not be different in the future. All our knowledge about nature and about the life of our soul is made up of complexes of ideas that have formed in our soul on the basis of observed connections between things and events. Reason can find nothing in itself that gives it the right to connect one idea with another, i.e. to make a cognitive judgment. From the moment Kant recognized the significance of Hume's investigations, his thinking took on a completely new direction. But he arrived at different conclusions from Hume himself as a result of Hume's considerations. He agreed with Hume that we cannot gain any information about a connection lying in things from mere reason. What laws things have in themselves, our reason cannot decide; only the things themselves can teach us. He also agreed with Hume that there is no unconditional and necessary certainty in the information that experience gives us about the connection between things. But on this, Kant maintained, we have perfect certainty that things must stand in the relation of cause and effect and in other similar relations. Kant did not lose his belief in absolutely necessary knowledge about reality as a result of Hume's statements. The question arose for him: How can we know something absolutely certain about the connection between things and events in reality, even though reason cannot decide how things relate to each other by their very nature and experience does not provide any absolutely certain information? Kant's answer to this question was: The necessary connection in which we see the things and phenomena we perceive does not lie in these things themselves, but in our organization. It is not because one event necessarily follows from another that we notice such a connection, but because our mind is so organized that it must connect things according to the concepts of cause and effect. Thus it does not depend on the things at all, but on us, in what relations they appear to us. Kant allows only sensations to be given by an external power. Their arrangement in space and time and their connection through concepts such as cause and effect, unity and multiplicity, possibility and reality, is, in his view, only accomplished by our mental organism. Our sensuality is such that it can only look at sensations in space and time, our intellect such that it can only think of them in certain conceptual relationships. Kant is therefore of the opinion that our sensuality and our intellect prescribe the laws of their connection to things and events. Whatever is to become the object of our experience must obey these laws. An examination of our organization reveals the conditions under which all objects of experience must necessarily appear. From this view arose for Kant the necessity of attributing to experience a character dependent on the human faculty of cognition. We do not know things as they are in themselves, but as our organization makes them appear to us. Our experience therefore contains only appearances, not things in themselves. Kant was led to this conviction by the train of ideas that Hume stimulated in him.