APL is a mistake, carried through to perfection.

The prisoner falls in love with his chains.

Raise your quality standards as high as you can live with, avoid wasting your time on routine problems, and always try to work as closely as possible at the boundary of your abilities. Do this, because it is the only way of discovering how that boundary should be moved forward.

Computer science has as much to do with computers as astronomy has to do with telescopes.

We are all shaped by the tools we use, in particular: the formalisms we use shape our thinking habits, for better or for worse, and that means that we have to be very careful in the choice of what we learn and teach, for unlearning is not really possible.

Progress is possible only if we train ourselves to think about programs without thinking of them as pieces of executable code.

In the software business there are many enterprises for which it is not clear that science can help them; that science should try is not clear either.