Robert W. Floyd quotes:

My message to the serious programmer is this: spend a part of your working day examining and refining your own methods. Even though programmers are always struggling to meet some future or past deadline, methodological abstraction is a wise long term investment.

The establishment of formal standards for proofs about programs [...] and the proposal that the semantics of a programming language may be defined independently of all processors for that language, by establishing standards of rigor for proofs about programs in the language, appears to be novel.

A semantic definition of a particular set of command types, then, is a rule for constructing, for any command of one of these types, a verification condition on the antecedents and consequents.

If there is ever a science of programming language design, it will probably consist largely of matching languages to the design methods they support.

It is, therefore, possible to extend a partially specified interpretation to a complete interpretation, without loss of verifiability, [...] This fact offers the possibility of automatic verification of programs, the programmer merely tagging entrances and one edge in each innermost loop.