Kant - A biography ~ Manfred Kuehn
. . . Kant believed that it is in our fortieth year that we finally acquire a character

No one who in his way of thinking is conscious of having character can have such character by nature. Rather, it must always be acquired. We may also assume that the foundation of this character and its beginning wiol be unforgettable. It is like a kind of rebirth, like a certain solemn kind of promise to oneself. Education, examples, and teaching cannot gradually bring about this firmness and constancy in principles, but it comes about only through an explosion, as it were, which follows all at once upon the dissatisfaction with the state of vacillation of instinct. There will perhaps only be few who have tried to accomplish this revolutin before their thirtieth year and even fewer who have firmly founded it before they are forty. The attempt at becoming a better human being in fragments is a futile undertaking, for one impression disappears as we work on another the foundation of a character is indeed the absolute unity of the internal principle of how to live in general. ` Page 144