However, the legal use of analogy is more like the scientific use than the ordinary use in the following sense: that the claim that X and Y are analogous is made with respect to some theoretical basis. The appeal is not (at least wholly) to perception. Rather the theoretical basis (in law, certain conventional rules of relevance established as precedents) gives us a decision procedure for determining whether or not cases X and Y are indeed analogous.

Ruggero J. Aldisert, Agatha D. Aldisert, Logic for Lawyers- A Guide …, loc. 608