Synthetic truths are true both because of what they mean and because of the way the world is, whereas analytic truths are true in virtue of meaning alone. “Snow is white,” for example, is synthetic, because it is true partly because of what it means and partly because snow has a certain color.

: a judgment that attributes to a subject a predicate not contained in the essence or connotation of that subject compare analytic judgment.

A synthetic proposition is a proposition that is capable of being true or untrue based on facts about the world - in contrast to an analytic proposition which is true by definition. For example, "Mary had a little lamb" is a synthetic proposition - since its truth depends on whether she in fact had a little lamb.

By 'synthetic philosophy' I mean a style of philosophy that brings together insights, knowledge, and arguments from the special sciences with the aim to offer a coherent account of complex systems and connect these to a wider culture or other philosophical projects (or both).