In the good old days physicists repeated each other's experiments, just to be sure. Today they stick to FORTRAN, so that they can share each other's programs, bugs included.

It used to be the program's purpose to instruct our computers; it became the computer's purpose to execute our programs.

In this respect a program is like a poem: you cannot write a poem without writing it. Yet people talk about programming as if it were a production process and measure "programmer productivity" in terms of "number of lines of code produced". In so doing they book that number on the wrong side of the ledger: we should always refer to "the number of lines of code spent".

About the use of language: it is impossible to sharpen a pencil with a blunt axe. It is equally vain to try to do it with ten blunt axes instead.

...Simplifications have had a much greater long-range scientific impact than individual feats of ingenuity. The opportunity for simplification is very encouraging, because in all examples that come to mind the simple and elegant systems tend to be easier and faster to design and get right, more efficient in execution, and much more reliable than the more contrived contraptions that have to be debugged into some degree of acceptability....Simplicity and elegance are unpopular because they require hard work and discipline to achieve and education to be appreciated.

A programming language is a tool that has profound influence on our thinking habits.

The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.