SEVENTEENTH AND EIGHTEENTH CENTURIES zyi 

 1781 — one of the most epoch-making works in the whole history of human 

 development. Kant's purpose — which, in fact, he at least partly achieved 

 ^ — is to lay the foundations of a new philosophy, to meet not only all the 

 needs of human life in the way of knowledge, but also its moral and religious 

 aims. The many different points of view from which he examines the work- 

 ings of the human mind, as well as the laws he lays down therefor, cannot 

 of course be recounted here. Chief in importance for the future advancement 

 of natural science is his attempt to determine what justification natural 

 science has for assuming the truth of the knowledge of nature which it 

 expounds. Kant first of all discusses the ideas of space and time and finds 

 that they are not grounded in experience, but in human nature itself; all 

 experience, on the contrary, is based on our having the ideas of space and 

 time that we have. And the same part that time and space play in our views, 

 the idea of causes plays in our understanding. The knowledge we gain by 

 experience is a knowledge of the phenomena that appear to us owing to 

 our organization's being what it is. What those things that cause the phe- 

 nomena are like in themselves we can never know for certain. Natural 

 science is thus a knowledge of reality such as we observe it, not a knowledge 

 of reality as it actually is. Natural laws are based on our own capacity for 

 knowledge and are binding on us because this capacity has certain funda- 

 mental qualities that are the same for all men. Natural science is thus fully 

 justified in drawing its conclusions in the world of experience; on the other 

 hand, it can never give any enlightenment as to the intrinsic meaning of 

 things — that is, what is not phenomenon — nor indeed does it need to do 

 so for the purpose of its physical explanations; but even if, say, some influ- 

 ences from the immaterial world were to arise, it should pass them over 

 and base its explanations upon what the senses are able to reveal and what 

 is reconcilable in accordance with the laws of experience, with our actual 

 observations. On the other hand, all things on which the experience of the 

 senses can give us no knowledge, such as what the soul, the world, God, 

 actually are in themselves, fall outside any rational knowledge. Of these 

 things, then, we can know nothing — we can maintain neither their exist- 

 ence nor their non-existence. But for that very reason we are able, if our 

 feelings require it, to take them for granted; we are justified in believing in 

 God, in the immortality of the soul, and in the free will, and reason has 

 no right to reject any such belief as irrational. These things are, in fact, a 

 part of practical reason — that sense of duty and right which Kant is firmly 

 convinced is inherent in everyone; that which says, not ivhy we act in this 

 or in that way, but hotv we should act in order to obey the dictates of con- 

 science within us. — Kant himself, in spite of his keen criticism of the 

 life of the human soul, was an ideally minded personality throughout — 

 an enthusiast over such questions as human justice and social equality, who 



