Abstract

In his 1686 essay GI Leibniz undertook to reduce sentences to noun-phrases, truth to being. Such a reduction arose from his equating proof with conceptual analysis. Within limits Leibniz’s logical calculus provides a reasonable way of surmounting the dichotomy, thus allowing a reduction of hypothetical to categorical statements. However it yields the disastrous result that, whenever A is possible and so is B, there can be an entity being both A and B. Yet, Leibniz was in the GI the forerunner of 20th century combinatory logic, which (successfully!) practices - sometimes for reasons not entirely unlike Leibniz’s own grounds - reductions of the same kinds he tried to carry out.