All the interests of my reason, speculative as well as practical, combine in the three following questions: 1. What can I know? 2. What ought I to do? 3. What may I hope?

Human reason is by nature architectonic.

What can I know? What ought I to do? What may I hope?

Nature does nothing in vain, and in the use of means to her goals she is not prodigal.

Thoughts without content are empty, intuitions without concepts are blind... The understanding can intuit nothing, the senses can think nothing. Only through their union can knowledge arise.

Here I shall add that the concept of change, and with it the concept of motion, as change of place, is possible only through and in the representation of time. & Motion, for example, presupposes the perception of something movable. But space considered in itself contains nothing movable; consequently motion must be something which is found in space only through experience -in other words, is an empirical datum.

The only thing permanent is change.