Any attempt to reduce the complex properties of biological organisms or of nervous systems or of human brains to simple physical and chemical systems is foolish.

Even personal tastes are learned, in the matrix of a culture or a subculture in which we grow up, by very much the same kind of process by which we learn our common values. Purely personal tastes, indeed, can only survive in a culture which tolerates them, that is, which has a common value that private tastes of certain kinds should be allowed.

One advantage of exhibiting a hierarchy of systems in this way is that it gives us some idea of the present gaps in both theoretical and empirical knowledge. Adequate theoretical models extend up to about the fourth level, and not much beyond. Empirical knowledge is deficient at practically all levels.

A somewhat casual observer from outer space might well deduce that the course of evolution in this planet had produced a species of large four-wheeled bugs with detachable brains; peculiar animals which rested when they sent their brains away from them but performed in rather predictable manner when their brains were recalled.

The only religion that still demands human sacrifice is nationalism.

In view of the importance of philanthropy in our society, it is surprising that so little attention has been given to it by economic or social theorists. In economic theory, especially, the subject is almost completely ignored. This is not, I think, because economists regard mankind as basically selfish or even because economic man is supposed to act only in his self-interest; it is rather because economics has essentially grown up around the phenomenon of exchange and its theoretical structure rests heavily on this process.

Deciding under uncertainty is bad enough, but deciding under an illusion of certainty is catastrophic.