Abstract: Modern science relies heavily on Galilean idealization, which establishes ceteris paribus laws—laws about what happens when a factor operates unimpeded. But these laws are of little direct use since factors seldom do operate unimpeded. The follow-up to Galilean idealization is abstraction—we talk simply of what the factor does. The best way to understand this abstraction is as an ascription of a capacity, not in terms of any kind of laws. Even the process of ‘de-idealization’ or of ‘concretization’ that results in a concrete phenomenological law inevitably involves further concepts in the capacity family.

Keywords: abstraction, ceteris paribus laws, concretization, de-idealization, Galilean idealization,