 There are two subfields in which chemists sometimes speak of logics or procedures for discovery. The first is synthetic chemistry. E.J. Corey (Corey &amp; Cheng 1989) has proposed that the synthesis of organic molecules can be rationally planned according to the logic of retrosynthetic analysis. Systematizing a long tradition in synthetic organic chemistry, Corey shows how one can reason backwards from a target molecule by finding a series of “disconnections,” bonds which one knows how to make. The resulting tree of disconnections gives potential pathways for synthesis that can then be evaluated by plausibility, or simply tried out in the laboratory.