Program testing can be used to show the presence of bugs, but never to show their absence! - Edsger W. Dijkstra

Testing can only prove the presence of bugs, not their absence. –

Testing shows the presence, not the absence of bugs

Industry suffers from the managerial dogma that for the sake of stability and continuity, the company should be independent of the competence of individual employees. Hence industry rejects any methodological proposal that can be viewed as making intellectual demands on its work force. Since in the US the influence of industry is more pervasive than elsewhere, the above dogma hurts American computing science most. The moral of this sad part of the story is that as long as computing science is not allowed to save the computer industry, we had better see to it that the computer industry does not kill computing science.

Please don't fall into the trap of believing that I am terribly dogmatic about [the go to statement]. I have the uncomfortable feeling that others are making a religion out of it, as if the conceptual problems of programming could be solved by a simple trick, by a simple form of coding discipline!

Program testing can be a very effective way to show the presence of bugs, but it is hopelessly inadequate for showing their absence.