 In his "History of Western Philosophy", Bertrand Russell went so far as to claim that Leibniz had developed logic in his unpublished writings to a level which was reached only 200 years later.Russell's principal work on Leibniz found that many of Leibniz's most startling philosophical ideas and claims (e.g., that each of the fundamental monads mirrors the whole universe) follow logically from Leibniz's conscious choice to reject "relations" between things as unreal.He regarded such relations as (real) "qualities" of things (Leibniz admitted unary predicates only)