Are There Synthetic Truths?

Are There Synthetic Truths?

There is a tradition, stemming from Quine (but not pre-dating him), claiming that the concept of analytic truth is undefined, or ill-defined, so that the analytic-synthetic distinction cannot be made sense of; accordingly, there are only synthetic truths. I think this is the opposite of the truth. Nothing is true but reality makes it so, Quine tells us, contrasting reality with meaning. And it is routine to hear that a synthetic truth is one that is true “in virtue of the world” (not language)—or perhaps in virtue of “the facts”, or “extra-linguistic reality”. But these formulations are by no means clear and run into immediate objections. In the first place, language and meaning are clearly part of reality or the world, so reality or the world cannot be construed as excluding them: yes, nothing is true but reality makes it so, but the reality can be either meaning or non-meaning. It might be thought that there is an easy fix: just say that a synthetic truth holds in virtue of non-linguistic reality. Now the problem is that some synthetic propositions are about linguistic reality—take any statement about the languages of the world or what a particular word means. Clearly, we need to say that a synthetic truth is non-analytic, but (a) that would not suit Quine (though it’s fine by me) and (b) it is purely negative. This throws us back to talk of reality and the world and facts: we need to say that synthetic truths concern the part of reality that doesn’t include facts constituted by meaning relations (or something along these lines). Now a new problem confronts us: what is this entity and what composes it? Is it a totality of facts, a totality of objects, of objects and properties, of facts and values, etc.? This is beginning to sound ominously metaphysical, inherently contentious, and probably meaningless. And there is this problem: presumably we can’t mean that a given proposition is true in virtue of the whole of this world, or else each proposition is made true by the same thing; so, we need to say that parts of the world correspond to each synthetic proposition (unlike analytic propositions). This puts us on a familiar and dreary path: logical atomism, negative facts, complexes of objects, and the difficulty of supplying identity conditions for the putative truth-making entities. We didn’t think we had signed up for this rigmarole when we declared that there are synthetic truths! But we started talking about “the world” so what did we expect? We are thus driven back to saying that synthetic truths are non-analytic truths, with no positive characterization of them given (as well as uncritical acceptance of analytic truth). And here the nub of the matter emerges from the mist: the concept of the synthetic is parasitic on the concept of the analytic. It is the concept of truth in virtue of meaning that wears the trousers (as Austin would say): we need that concept if we are to carve out a territory labeled “synthetic truth”. The latter concept has no content without the former concept. It would be different if we could define “synthetic” as (say) “perceived by the senses”, because then we wouldn’t have to make do with the amorphous concept the world; but that is obviously too narrow, too restrictive. The problem is that the class of truths that are not analytic is a ragbag possessing no inner unity; it isn’t a natural metaphysical kind. Its sole content is given by the concept of the analytic, which trades in the restricted (and legitimate) concept of meaning. Note that “synthetic” is not a very descriptive term; it is really just a label for what is left over when we have listed all the analytic truths. The concept lives and dies by its contrast class. But that means that we have no unitary positive concept of the synthetic suitable for bringing together all that is supposed to fall under it. Moreover, we have a decent criterion of identity for meanings, viz. substitutivity inside belief contexts, but we don’t have such a criterion for whatever is supposed to make synthetic propositions true. Hence the vague and woolly talk of the “world” and “reality”. There is the general concept of truth and the specific concept of analytic truth, but there is no concept of synthetic truth save a hopelessly disjunctive one. It is the “craving for generality” that leads us to think that we have identified a metaphysical natural kind. All we really have is a philosopher’s invention—a contrivance, a fabrication. It is certainly not a concept of science, or even of linguistics. So, we cannot hope to base a philosophy on the concept of synthetic truth, saying such things as that all truths are synthetic; all that can mean is that no truths are analytic, relying on an antecedent grasp of that concept. This is obviously no help to a disciple of Quine, but even a firm believer in analyticity won’t be encouraged by a concept so negatively defined. I think myself that analytic truth is adequately defined as truth in virtue of meaning alone, but that synthetic truth has no adequate definition—certainly not one in terms of truth in virtue of “the world” or “reality”. You might hope to define it as “what is known by empirical investigation”, but that is objectionably epistemic (what if the truth can’t be known?), and also fails to count knowledge of one’s own mental states as knowledge of synthetic truths.[1] There is, in fact, little effort to define the category of the synthetic, so that the concept is left at a vague and intuitive level, explained more by example than by general definition. To say that all meaningful statements are (or must be) synthetic is therefore meaningless metaphysics, which is ironic in the circumstances. We literally don’t know what it means (Kant has a lot to answer for). In its ordinary use the word means “not genuine; unnatural” (OED) and that does indeed correspond to something real: for the idea of a synthetic truth is a synthetic idea, i.e., a fake classification. There are no synthetic truths (but plenty of analytic truths); there are just truths that fail to be analytic—as there are many types of truths that fail to be ethical or psychological or economic or about me. Not belonging to the class of analytic truths is not a way of forming a unified class of other truths. We can distinguish classes of truths within the non-analytic class, but no positive trait unifies them, whereas analytic truths form a well-defined class. It is the concept of analytic truth that is in good theoretical shape not the concept of synthetic truth. And isn’t this what any card-carrying rationalist would say?[2]

[1] The OED is uncharacteristically unhelpful here: as its second definition of “synthetic” it gives us “having truth or falsity determinable by recourse to experience” (this is relegated to Logic). This is a frankly epistemic definition of what should be a logical or metaphysical concept, and is therefore a kind of category mistake. It fits the concept of the a posteriori better. Also, how is it supposed to apply to the synthetic a priori, as in arithmetic? Such truths are not verifiable by “recourse to experience” yet are supposed synthetic. Nor do we know that we have beliefs by sense experience (and what other kind of experience is intended?). It looks to me as if the dictionary makers took the philosophers on trust and did the best they could with a dubious (spurious) notion.

[2] The concept of empirical truth is similar in view of the enormous variety of things that fall under the concept of experience. How unified is this class really? Is it as unified as the class of a priori truths? Empiricism is just not a monolithic unified theory, and nor is “synthetism” defined as the doctrine that all truths are synthetic. The metaphysics of these theories is not well defined, i.e., what it is to be an experience or a synthetic truth. More dogmas of empiricism (rationalism fares much better in this respect).

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