Abstract

The paper discusses some logical problems concerning analogy. The traditional understanding of analogy as _proportion_ (proportion) is inadequate, at least if proportionality is taken in mathematical sense. This situation is clear if we considered various special cases of analogy for instance _analogia legis_ and _analogia juris._ Since analogy assumes a similarity of analogata (items being or investigated) as analogical, a general analysis of analogical relation must begin with the concept of similarity. It can be defined as possessing a common property. This idea is formalized by devices borrowed from logic and set theory.