What does 'identify' mean? The trouble with common words is the looseness of their definition and broadness of interpretation.

Such loose definitions spell trouble for writing complex programs. Loose specifications are interpreted by programmers who substitute their own more specific definitions. Such is the trouble with other vague terms like 'equality', 'identity', and 'reference'. To grapple with complex systems is to grapple with language, to turn loose to strict, and vague to precise.

English is often too imprecise and must be complemented with mathematical models. A 'sphere' has a definition, yet for some circumstances may not be sufficient. We often employ sphere to describe the Earth, Moon and golf balls, yet sphere doesn't truly describe the shape of these objects, it's an imprecise abstraction. Does it matter? It depends, and that is the trouble.

Thinking about the language we use and aspiring to be more precise might help us order our own thoughts, communicate more clearly, and avoid undesirable consequences.