Inspired by John Locke, he was an early proponent of causal theories of perception, knowledge, and memory, and a principal architect of Australian metaphysical realism.
2.
In The Causal Theory of Perception', Grice contrasts saying ( which he there also calls " stating " ) with " implying ", but in Logic and Conversation he introduces the technical term " implicature " and its cognates " to implicate " and " implicatum " ( i . e ., that which is implicated ).