In the computer field, the moment of truth is a running program; all else is prophecy.

All correct reasoning is a grand system of tautologies, but only God can make direct use of that fact

Engineering, medicine, business, architecture and painting are concerned not with the necessary but with the contingent - not with how things are but with how they might be - in short, with design.

Most of what we do to get people ready to act in situations of encounter consists of drilling these lists into them sufficiently deeply so that they will be evoked quickly at the time of the decision.

Anything that gives us new knowledge gives us an opportunity to be more rational.

Human knowledge has been changing from the word go and people in certain respects behave more rationally than they did when they didn't have it. They spend less time doing rain dances and more time seeding clouds.

The aim ... is to provide a clear and rigorous basis for determining when a causal ordering can be said to hold between two variables or groups of variables in a model . . . . The concepts refer to a model-a system of equations-and not to the 'real' world the model purports to describe.