How do vague notions about how one might understand certain physical phenomena get transformed into scientific concepts such as “field”, “quark”, and “gene”? Philosophers of as disparate views as Reichenbach and Feyerabend have held that the process through which scientific concepts emerge is not a reasoned process. In a manner completely mysterious and unanalyzable, scientific concepts emerge fully grown, like Athena from the head of Zeus. However, when one examines actual cases of concept formation in science, a different picture can (...) be painted: Scientific concepts do not pop out of heads, but are constructed in response to specific problems by utilizing methods appropriate to the solution of the problem. Thus, as with other aspects of the scientific enterprise, concept formation is a problem-solving process that involves the application of systematic procedures in the attempt to solve specific problems. It is a reasoned process. (shrink)