As a rule, software systems do not work well until they have been used, and have failed repeatedly, in real applications.

We must not forget that the wheel is reinvented so often because it is a very good idea; I've learned to worry more about the soundness of ideas that were invented only once.

When someone builds a bridge, he uses engineers who have been certified as knowing what they are doing. Yet when someone builds you a software program, he has no similar certification, even though your safety may be just as dependent upon that software working as it is upon the bridge supporting your weight.

One bad programmer can easily create two new jobs a year.

Many spend their time berating practitioners for not applying their method. We all need to disseminate our ideas, but most of our time should be spent applying and improving our methods, not selling them. The best way to sell a mouse trap is to display some trapped mice.

I have found that the reason a lot of people are interested in artificial intelligence is the same reason a lot of people are interested in artificial limbs: they are missing one.

With software products, it is usual to find that the software has major `bugs' and does not work reliably for some users... The lay public, familiar with only a few incidents of software failure, may regard them as exceptions caused by exceptionally inept programmers. Those of us who are software professionals know better; the most competent programmers in the world cannot avoid such problems.