Real wisdom is not the knowledge of everything, but the knowledge of which things in life are necessary, which are less necessary, and which are completely unnecessary to know.
Leo TolstoyThere are two methods of human activity - and according to which one of these two kinds of activity people mainly follow, are there two kinds of people: One use their reason to learn what is good and what is bad and they act according to this knowledge; the other act as they want to and then they use their reason to prove that that which they did was good and that which they didn't do was bad.
Leo Tolstoy