problem-solving leaders have one thing in common: a faith that there's always a better way. - Gerald M. Weinberg

More often, then, we will be doing evaluation of programs not with respect to one another but with respect to a situation — a total situation — in which they are developed. Looking honestly at the situation, we are never looking for the best program, seldom looking for a good one, but always looking for one that meets the requirements.

"Testing may convincingly demonstrate the presence of bugs, but can never demonstrate their absence."- Edsger W. Dijkstra, Computing Pioneer (1930–2002), "Programming as a discipline of mathematical nature," Am. Math. Monthly, 81 (1974), No. 6, pp. 608–12.

Systems are complex. A computer system is not just hardware, not just software, not even just people plus hardware plus software. The procedures, formal and informal, that have evolved with the system are part of the system; so is the current load on various components, and so is the attitude and experience of the users. Even among the commonly accepted “parts” of a system, clear lines of separation do not exist. Hardware merges with operating system, operating system merges with programming language, programming language merges with debugging tools, debugging tools merge with documentation, and documentation merges with training, and all of them mingle with the social climate in which the system is used.