Thursday, October 14, 2004

Is There a Place for Truth in the Naturalist's World?

Note: This is an excerpt from an article in progress. Comments welcome.

Victor Reppert gives the following argument from truth against naturalism.

1. If naturalism is true, then no states of the person can be either true or false.
2. Some states of the person can be either true or false.
Therefore,
3. Naturalism is false.

As it stands, this argument is not convincing. I will first explain why it is not convincing, and then show how the argument can be fortified to meet plausible objections. But first a distinction.

Primary, Secondary, and Tertiary Truth-Bearers

My reformulation of Reppert’s argument requires a distinction between primary and secondary truth-bearers, where a truth-bearer is any entity that can be meaningfully characterized as either true or false. That there are truth-bearers I take to be a ‘Moorean fact’ beyond the reach of reasonable dispute; reasonable controversy first begins with the question as to what they are. Any theory, including any version of naturalism, that has as a logical consequence that there are no truth-bearers is inconsistent with the conditions of its own truth, and thus self-refuting. I also take it to be self-evident that not everything is a truth-bearer: not everything can be meaningfully characterized as either true or false. A belief is a possible candidate for the office of truth-bearer; a banana is not.

To appreciate what is meant by the primary/secondary distinction, consider an occurrent belief (that it is time for lunch, for example) and its verbal expression (a spoken or written token of ‘It is lunch-time’). ‘True’ and ‘false’ are predicable both of beliefs and their verbal expressions; so both beliefs and their expressions count as truth-bearers. But they are not truth-bearers in the same way. The belief, as compared to its expression, takes priority: it is the primary truth-bearer while the expression is secondary. The expression is true because the belief it expresses is true, and not vice versa. It would be incoherent to say that the occurrent belief is true because its verbal expression is true.

Although it is clear that the belief takes priority over its expression, it may be that there is a truth-bearer that takes priority over a belief. Suppose for a moment that Frege is right, and that Gedanken or thoughts, understood in his idiosyncratic way as the senses of context-free sentences in the indicative mood, are the primary truth-bearers. (A context-free sentence is one from which all demonstrative and indexical elements have been expunged, including tenses of verbs.) It would then be reasonable to say that beliefs formed when one affirms a true thought (or Fregean proposition) are true in a secondary sense, and that verbal expressions of such beliefs are true in a tertiary sense. I am not endorsing Frege’s conception; indeed, I will be arguing against it. I invoke it merely to illustrate the primary/secondary/tertiary distinction.

Now for the reformulation of Reppert’s argument.

Reppert Reformulated

Given the distinction just made, Reppert’s original argument is ambiguous as between the following two arguments, call them the *argument and the **argument.

1*. If naturalism is true, then no mental state is a primary truth-bearer.
2*. Some mental states are primary truth-bearers.
Therefore,
3. Naturalism is false.

1*. If naturalism is true, then no mental state is a primary truth-bearer.
2**. Some mental states are secondary truth-bearers.
Therefore
3. Naturalism is false.

The **argument can be dismissed right away. It falls afoul of the dreaded quaternio terminorum fallacy. In plain English, there are four terms, hence no middle term. This leaves the *argument. My claim is that the *argument, though valid and possessing true premises, begs the question against the naturalist in its second premise. (I suspect that the question-beggingness of the *argument is easily missed due to its conflation with the **argument in Reppert’s original argument.) That is, no sophisticated naturalist will allow that some mental states are primary truth-bearers. A naturalist who would allow this would be allowing the ontological primacy of mind when the whole point of naturalism is to deny such primacy. Permit me to explain.

A necessary condition of being a naturalist is the insistence that mind is ontologically dependent (dependent in its existence) upon the natural world. The dependence can be spelled out in a variety of ways giving rise to a variety of naturalisms. Some naturalists say that mind is epiphenomenal, others that it is emergent, still others that it is supervenient, while the most extreme of all say that it is reductively identifiable with brain processes ( Identity Theory) or with overt behavior and behavioral dispositions (Behaviorism). The naturalists’ main point, however, is that mind cannot exist without a material substratum of a certain complexity and organization: there are no disembodied minds, hence no God as classically conceived, no souls capable of pre-existing or post-existing their embodiment, no angels or demons.

But surely there are truths that hold at times when there are no minds. The thesis of naturalism itself, if true, is such a truth. At the time of the Big Bang, and for a good long time thereafter, natural conditions were not such as to permit the existence of any minds; yet naturalism, if true, was true during this period. It was true during this period that nothing could be a mind unless it were based in matter of the right organization and complexity. Naturalism did not first become true when minds first emerged. As a truth about minds, it is true, if it is true, independently of any and all minds. And the same goes for infinities of other truths that do not depend on the existence of minds. Among these are truths about the physical universe and its parts. Thus it was true before any minds evolved on earth that the earth was a spheroid with one moon, possessed an atmosphere of such-and-such a composition, etc. There are also necessary truths to contend with: they are true in every possible world, including worlds in which minds do not exist. Thus it is quite clear that the existence of truths in general cannot depend on the existence of the sorts of minds that naturalists will allow into their ontologies, namely, minds whose very existence depends on the existence of highly organized configurations of matter. (The special case of truths about minds is consistent with this general point.)

It follows that a sophisticated naturalist will not grant that some mental states are primary truth-bearers. The reason, again, is that there must be primary truth-bearers at times and in possible worlds in which minds do not exist. Such a naturalist will not grant the classical thesis of Thomas Aquinas et al. according to which truths reside only in minds to the extent that they correspond to external reality, as in the scholastic dictum, Veritas est adaequatio intellectus et rei. If truth consists in a correspondence between mind and reality, then mind must exist if truth is to exist. Theists such as Augustine and Aquinas will use this point to argue for the existence of a necessarily existent infinite mind. The sophisticated naturalist will hold instead that primary truth-bearers are some species of abstract object such as Fregean propositions that exist in sublime independence of any and all minds. This does not imply that the sophisticated naturalist cannot say of beliefs that they are true or false; it implies merely that he cannot attach these predicates to beliefs in the primary sense.

No sophisticated naturalist should lose any sleep over Reppert’s argument. A convincing argument from truth against naturalism must therefore show that the primary truth-bearers cannot be abstract objects. To this task I now turn. To anticipate my conclusion: Primary truth-bearers cannot be abstract objects any more than they can be physical objects; they must be states of mind. Since this cannot be allowed by any naturalist who understands that some truths are independent of matter-based minds, naturalism is false.