The Irreducibility of Propositional Content

The Irreducibility of Propositional Content

The Irreducibility of Propositional Content

In my previous book on the argument from reason, I generated six versions of the argument from reason. I am going to talk about one of them, what I called in my book the argument from propositional content—the argument that if science is true, then we as human beings are in states with determinate propositional content; but if naturalism is true, we should never be in such propositional states. In order to satisfy the epistemological commitments of philosophical naturalism, naturalists must affirm that we are in determinate propositional states. In order to satisfy their metaphysical commitments, naturalists must deny that we are ever in determinate propositional states.

James Ross, in his essay“Immaterial Aspects of Thought,” presents an argument against a physicalist account of propositional content which I will call the Argument from Determinate Content. He writes:

Some thinking (judgment) is determinate in the way no physical process can be. Consequently, such thinking cannot be a (wholly) physical process. If all thinking, all judgment, is determinate in that way, no physical process can be (the whole of) any judgment at all. Furthermore,“functions” among physical states cannot be determinate enough to be such judgments, either. Hence some judgments can be neither wholly physical processes nor wholly functions among physical processes.⁵

Yet, he maintains, we cannot deny that we perform determinate mental operations. He writes:

I propose now, with some simple cases, to reinforce the perhaps already obvious point that pure function has to be wholly realized in the single case, and cannot consist in the array of“inputs and outputs” for a certain kind of thinking. Does anyone deny that we can actually square numbers?“4 times 4 is sixteen”; a definite form (N x N = N²) is“squaring” for all relevant cases, whether or not we are able to process the digits, or talk long enough to give the answer. To be squaring, I have to be doing some thing that works for all the cases, something for which any relevant case can be substituted without change in what I am doing, but only in which thing is done.⁶

I should add that if we don't literally add, subtract, divide, multiply, square numbers, and take their square roots, not to mention perform all the complicated mathematical operations involved in, say, Einstein's theory of relativity, then physicalism, which not only says that reality is physical but that physics, at least approximately, gets it right, is up the creek without a paddle.

Ross's argument can be formalized as follows.

Some naturalistic theories have been developed to provide a physicalist account of intentionality. Feser delineates four types of theories of this nature: conceptual role theories, causal theories, biological theories, and instrumentalist theories.

Conceptual role theories explicate intentional states in terms of their conceptual roles, that is, in relation to other intentional states. Of course, this does not explain why there is a network of intentional states in the first place.⁷

A more popular approach to coming up with a naturalistic account of intentionality is causal theories of intentionality. These appeal to the causal relations that intentional states stand to items in the external world. Thus if I believe that there is a computer monitor in front of me as I type these words, there is a causal connection between the monitor and my visual cortex, which causes states of my brain to be affected by it.

Causal theories of reference have certainly been advanced, but many of these do not suggest that causal relationships alone are sufficient to fix reference. On a Kripkean view of the causal theory of reference, a name's referent is fixed by an original act of naming (also called a“dubbing” or, by Kripke, an“initial baptism”), whereupon the name becomes a rigid designator of that object. Later uses of the name succeed in referring to the referent by being linked to that original act via a causal chain. In other words, what causation explains, according to this theory, is how references are transmitted once an initial act of naming, an intentional state (both in the sense of being intended and in the sense of possessing“aboutness”), is performed. How such actions could be performed in the first place is not accounted for in causal terms. To do the work the naturalist requires, we need to explain even the initial act of naming in causal terms.

When we start talking about propositional states, we have to ask how any specification of causal relations can possibly entail the existence of meaning at all. Let us say a bird is hardwired to let out a certain squawk when something approximately the shape of a hawk is nearby. There is a regular causal relation between the appearance of a hawk and the occurrence of the squawk. In one sense we can say that the squawk is about the hawk. Something could, of course, touch off the“hawk” signal and the subsequent evasive action without being a hawk. It does not mean that the bird has the ability to distinguish a hawk from any and all nonhawks. A properly constituted doppelgänger could fool it. Expecting fire when one sees smoke is not the same as inferring fire from smoke. We say that“smoke means fire,” but what this amounts to is that smoke and fire are often conjoined in experience. We often experience smoke before we experience fire, but it turns out upon examination of the causal relations that fire causes smoke and not vice versa. We say that“smoke means fire,” but that means smoke and fire are conjoined in our experience. The“meaning” is imposed by human understanding, not in the world as it is in itself.

As Feser writes:

Any account of such theories could give the relevant causal relations holding between a particular mental state and a particular object in the external world will require picking out a particular object in the beginning point of the causal series (call it A) and a particular end point (B) as the mental state doing the representing.…Nothing in the flux objectively either the determinate starting point or a particular sequence or the determinate ending point. It is we who pick certain events and count them as beginnings and endings; their status as beginnings and endings is relative to certain purposes and interests of ours.⁸

In short, there is a difference between causing action appropriate to something being the case (causing the bees to go where the nectar is) and declaring it to be the case that the nectar is in such and such a place. Science is inherently declarative, and requires understanding. It is tempting but erroneous to attribute a declarative character to bee dances and birdsongs. Casual connections are invariably insufficient to provide determinacy of propositional content. Without determinacy of propositional content, the type of rational inference in science cannot occur.

Another theory looks to biological role or function as a basis of determining content. However, Dennett has successfully argued that biological function also leaves propositional content indeterminate. Evolutionary function is essentially fluid in nature, and to get something as determinate as propositional content out of biological function is asking too much of it. (What is the biological function of feathers on a bird?)

John Searle writes:

So far no attempt at naturalizing content has produced an explanation (analysis, reduction) of intentional content that is even remotely plausible. A symptom that something is radically wrong with the project is that intentional notions are inherently normative. They set standards of truth, rationality, consistency, etc., and there is no way that these standards can be intrinsic to a system consisting entirely of brute, blind, nonintentional causal relations. There is no mean [middle] component to billiard ball causation. Darwinian biological attempts at naturalizing content try to avoid this problem by appealing to what they suppose is the inherently teleological [i.e., purposeful], normative character of biological evolution. But this is a very deep mistake. There is nothing normative or teleological about Darwinian evolution. Indeed, Darwin's major contribution was precisely to remove purpose, and teleology from evolution, and substitute for it purely natural forms of selection.⁹

Or as Feser puts it:

Talk of purposes and functions, if taken literally, seems to presuppose intentionality; in particular it seems to presuppose the agency of an intelligence of one who designs something for a particular purpose. But the aim of Darwinian evolutionary theory is to explain biological phenomena in a manner that involves no appeal to intelligent design.…Just as modern physics has tended to explain phenomena by carving off the subjective qualitative appearances of things and relocating them into the mind, so too did the Darwinian revolution in biology push purpose and function out of the biological realm, making them out to be mind-dependent and devoid of objective reality.¹⁰

In point of fact, the ruthless naturalist W. V. Quine has argued that the reference of our terms is indeterminate and that there is no fact of the matter as to what our words refer to.¹¹ However, this has disastrous consequence for the practice of science. Only if our terms have determinate reference can we reason to conclusions. Consider the following argument about the unsharpened pencil.

The argument's confusion about meaning makes an apparently valid argument invalid.

Our ability to reason logically can exist only if we are able to identify sameness of meaning. Dennett's view of the mind essentially affirms the Quinian thesis of indeterminacy, and indeed Dennett thinks this kind of indeterminacy is a consequence of philosophical naturalism.

And why not? Here, I think, we find as powerful and direct an expression as could be of the intuition that lies behind the belief in original intentionality. This is the doctrine Ruth Millikan calls meaning rationalism, and it is one of the central burdens of her important book, Language, Thought, and Other Biological Categories, to topple it from its traditional pedestal.…Something has to give. Either you must abandon meaning rationalism—the idea that you are unlike the fledgling cuckoo not only in having access, but in having privileged access to your meanings—or you must abandon the naturalism that insists that you are, after all, just a product of natural selection, whose intentionality is thus derivative and hence potentially indeterminate.¹²

If meanings are indeterminate, then it's indeterminate what Dennett means by anything he says. No one can possibly determine whether any argument is valid because if, say, it's a categorical syllogism, there's no way to determine whether we've got three terms, four terms, five terms, or six terms. So let's have a look at Dennett's argument.

And here's mine.

Perhaps the indeterminacy of meaning is benign and not such that it undermines science in the radical way in which I have described. Consider Kripke's distinction between addition and what he calls“quaddition,” where addition has the form x + y but quaddition has the form x + y if x and y are less than 57, 5 otherwise.¹³ If mathematics is indeterminate between addition and quaddition, science is in trouble.

Another approach to intentionality, attributed to Dennett, regards propositional states in instrumental terms. That essentially makes all intentionality derived intentionality. But derived from what? If we have intentionality because we take ourselves to have intentionality, then how do we account for the intentional state of taking ourselves to have intentionality?

A number of arguments have been presented against the possibility of reducing determinate beliefs and desires to physical states. Quine's argument for the indeterminacy of translation, Kripke's adapted Wittgenstein argument, Davidson's argument against psychophysical laws,14 and Nagel's discussions in The Last Word¹⁵ have this implication. However, different philosophers have drawn different conclusions from the arguments for irreducibility. Since reason cannot be reduced to physical relations, materialists have to use other strategies to fit reason into a physicalist world.

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