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.

The proper study of mankind is the science of design.

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.

The world is vast, beautiful, and fascinating, even awe-inspiring - but impersonal. It demands nothing of me, and allows me to demand nothing of it.

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

A wealth of information creates a poverty of attention.

I don't care how big and fast computers are, they're not as big and fast as the world.