Philosopher. Kant is considered by some to be the greatest philosopher, or at least European philosopher, who ever lived. In addition to pointing out that the reality we observe will always be shaped by our mind, he tried to place morals on a firm foundation of logic through his celebrated Categorical Imperative, which held that actions can only be justified if we wished everyone else to emulate them. A professor of fixed habits, he lived all his life in one city and devoted himself totally to scholarship and philosophy.