Time is not an empirical concept. For neither co-existence nor succession would be perceived by us, if the representation of time did not exist as a foundation a priori.
In the kingdom of ends everything has either a price or a dignity. Whatever has a price can be replaced by something else as its equivalent; on the other hand, whatever is above all price, and therefore admits of no equivalent, has a dignity. But that which constitutes the condition under which alone something can be an end in itself does not have mere relative worth, i.e., price, but an intrinsic worth, i.e., a dignity.
At some future day it will be proved, I cannot say when and where, that the human soul is, while in earth life, already in an uninterrupted communication with those living in another world.
Nature does nothing in vain, and in the use of means to her goals she is not prodigal. Her giving to man reason and the freedom of the will which depends upon it is clear indication of her purpose. Man accordingly was not to be guided by instinct, not nurtured and instructed with ready-made knowledge; rather, he should bring forth everything out of his own resources.
We ourselves introduce that order and regularity in the appearance which we entitle "nature". We could never find them in appearances had we not ourselves, by the nature of our own mind, originally set them there.
Most men use their knowledge only under guidance from others because they lack the courage to think independently using their own reasoning abilities. It takes intellectual daring to discover the truth.