Analytic-synthetic distinction

The analytic–synthetic distinction is a distinction used in philosophy to divide an ontology into two parts: an analytic part consisting of terms related by synonymy, and a synthetic part concerning connections between such terms and 'real' objects.

Analyticity and empiricism
In several books and papers, Quine challenged this division. Quine argued that although there are trivial situations in which analyticity prevails, those circumstances which simply replace some elaborate sequence of terms by a tautological equivalent, all interesting propositions in an ontology (all that do not involve simple use of definitions) are synthetic in nature, that is, they inevitably bring forward some empirical fact.

According to Putnam, Quine's position on analyticity is:

"“A statement is analytic if it can be turned into a truth of formal logic by substituting synonyms for synonyms.”"

- Hilary Putnam

The issue then turns upon whether 'synonym' has a meaning beyond simple tautology. An example involving simple tautology is that All bachelors are unmarried, which holds true simply because, by stipulation, someone is a bachelor if and only if they are unmarried. Quine argued there were no other kinds of analytic statements, and any attempt to extend 'synonymy' beyond such kinds of examples was doomed to failure. Analyticity is possible only by stipulation.

The target here was an interpretation of Carnap's work as saying that synonymy was not just a logical matter, but a matter of usage; stipulation could be extended to certain sense perceptions. Such a view seems to propose the matter of 'analyticity' is one not of logic, but of confirmation.

It is doubtful whether this interpretation of Carnap was accurate. Carnap was closer to Lewis in thinking that analytic statements were hypothetical and, while tautologically true within their formal structure, could be considered to have some empirical validity only by comparison with experiments. Their truth was not an undeniable consequence of analyticity within their formal structure, but a probabilistic matter dependent upon pragmatic considerations about utility of the formal structure. In this respect, Carnap and Lewis agree with Hawking/Mlodinow's proposal of model-dependent realism.