After an exposé of the programme involved, it is shown that the Gricean maxims fail to do their job in so far as they are meant to account for the well-known problem of natural intuitions of logical entailment that deviate from standard modern logic. It is argued that there is no reason why natural logical and ontological intuitions should conform to standard logic, because standard logic is based on mathematics while natural logical and ontological intuitions derive from a cognitive system in people's minds (supported by their brain structures). A proposal is then put forward to try a totally different strategy, via (a) a grammatical reduction of surface sentences to their logico-semantic form and (b) via logic itself, in particular the notion of natural logic, based on a natural ontology and a natural set theory. Since any logical system is fully defined by (a) its ontology and its overarching notions and axioms regarding truth, (b) the meanings of its operators, and (c) the ranges of its variables, logical systems can be devised that deviate from modern logic in any or all of the above respects, as long as they remain consistent. This allows one, as an empirical enterprise, to devise a natural logic, which is as sound as standard logic but corresponds better with natural intuitions. It is hypothesised that at least two varieties of natural logic must be assumed in order to account for natural logical and ontological intuitions, since culture and scholastic education have elevated modern societies to a higher level of functionality and refinement. These two systems correspond, with corrections and additions, to Hamilton's 19th-century logic and to the classic Square of Opposition, respectively. Finally, an evaluation is presented, comparing the empirical success rates of the systems envisaged.