I call it my billion-dollar mistake. It was the invention of the null reference in 1965.

I was eventually persuaded of the need to design programming notations so as to maximize the number of errors which cannot be made, or if made, can be reliably detected at compile time.

The price of reliability is the pursuit of the utmost simplicity. It is a price which the very rich may find hard to pay.

An ultimate joint challenge for the biological and the computational sciences is the understanding of the mechanisms of the human brain, and its relationship with the human mind.

The real value of tests is not that they detect bugs in the code but that they detect inadequacies in the methods, concentration, and skills of those who design and produce the code.

Programmers are always surrounded by complexity; we cannot avoid it.... If our basic tool, the language in which we design and code our programs, is also complicated, the language itself becomes part of the problem rather than part of its solution.

In the development of the understanding of complex phenomena, the most powerful tool available to the human intellect is abstraction. Abstraction arises from the recognition of similarities between certain objects, situations, or processes in the real world and the decision to concentrate on these similarities and to ignore, for the time being, their differences.