In a talk given on the Greenland Cruise conference on consciousness in 2014 Philip Goff describes two bitter pills which must, he argues, be swallowed by anyone who subscribes to ‘pure physicalism’, according to which “completed physics will give us one day the complete fundamental picture of reality” [4:19], an ontological view which Goff sees as the natural elongation of the weaker epistemological view that “we should look to and only to the physical sciences to tell us what fundamental reality is like” [2:55].
Those bitter pills are:
- Fundamental entities lack an intrinsic nature. [7:43]
- Consciousness can be accounted for in entirely causal terms. [11:05]
Goff argues that both of these are entailed by something he calls ‘dispositional essentialism’, which is in turn entailed by pure physicalism. Dispositional essentialism is the view according to which “there is nothing more to the nature of a fundamental property than what it disposes its bearer to do.” [6:40]
The thread Goff uses to link pure physicalism and dispositional essentialism is the oft-noted fact that all theories provided by the physical sciences, and all characterisations of the entities referred to in physical theories, are made in terms of dispositional properties. Physical theory doesn’t tell us what things are so much as what they do. (Goff gives the example of an electron: it is characterised as something having a certain mass and a certain charge, but those properties of mass and charge are themselves characterised in terms of what their bearers will do in the presence of other things.) And when it does tell us what something is, it does so by appealing to what other things do—heat is molecular motion, storms are systems of air currents moving in certain patterns, atoms are aggregates of quarks bonded to each other in various configurations, and so on. So if physical science can supply only theories concerning dispositions and relations, but nevertheless can supply a complete fundamental picture of reality (as the pure physicalist reckons), then it follows that a complete fundamental picture of reality will be purely dispositional in content.
Seeing that the second pill follows from this is just a matter of noting that a fundamental picture of reality should include everything that occurs in reality, including consciousness. Whether or not the pill really is bitter is, of course, subject to much dispute, and I will not get into it here (though I have done quite a lot recently—see here, here, here & here). Instead, in this post I shall talk a little about the first pill.
A thing’s instrinsic nature is what it is in and of itself, i.e. independently of how it relates to other things. Since dispositional properties concern a thing’s capacity to affect other things, dispositional properties are relational, i.e. extrinsic properties, and so dispositional essentialism certainly does entail that at the fundamental level there are no intrinsic natures, or, to put it another way, that insofar as there are any things with intrinsic properties, those properties are in some sense derivative of the extrinsic properties of other things (typically the things that constitute them).
(To clarify the terminology before things get messy: a relation holds of a certain number of things, called its arity. The relation ‘being greater than 7’ has arity 1, because it can only be applied to one thing (11 is greater than 7) whereas ‘being equal to’ has arity 2, because it is applied to two things (1+4 is equal to 2+3). An intrinsic property is just a relation with arity 1, and an extrinsic property is a relation with arity >1.)
Fair enough, but what’s wrong with this pill? By way of trying to convince his audience of its bitterness, Goff offers a few variations on a theme. He first points to a problem of regress in chains of analysis. Say we want to understand some property P. A successful analysis of P will have been reached when some other property Q (or properties—if so let Q be their conjunction) has been found which can be taken as defining P, i.e. such that the following holds:
Necessarily, P(x) if and only if Q(x)
Goff notes that any complete theory will, in addition to providing an analysis of P, have to provide an analysis of Q in terms of some other property—R—and then of R in terms of some other property, and so on. If this process is to come to an end, then it seems there must be at least some unanalysable (i.e. fundamental) properties at the end of the chains.
I will return to this inference later on in the post, but for the moment let’s agree with it and ask what it implies. Goff seems to think that it makes mischief for dispositional essentialism, presumably on the basis that only intrinsic properties could ground the chain. But why should this be so? Why could such a chain not end with an unanalysable extrinsic property?
Consider, to help make this clear, the property of being above 0 degrees Celsius. Applying what we know about heat being molecular motion, something is above 0 degrees Celsius when (and only when) the average kinetic energy of the molecules that compose it is above some value. This analysis represents one step down the chain of explanation, but even this simple example reveals an oversimplification in the equivalence above, namely that the property to be explained—being above 0 degrees Celcius—which holds of a single thing (i.e. it is an intrinsic property), has been analysed into a property—having an average kinetic energy above some value—which holds of a collection of things (i.e. it is an extrinsic property). This adds some nuance to the picture, indicating that there are some links in the chain of explanation which are going to look more like this:
Necessarily, P(x) if and only if Q(f(x))
Where f is the function that maps wholes onto their parts. But if this is the case, then Q may very well be a relation which holds of a collection of things, rather than of a single thing. The point here—perhaps I’m labouring it a little—is just that as we step over the biconditionals, moving through the list of properties along the chain of explanation, the arity of the explaining properties may grow. But if this is the case, why should we expect the property at the end of it to be instrinsic, rather than extrinsic?
So the problem of regress in chains of explanation is ambivalent about whether chains end in extrinsic or intrinsic properties. But perhaps there’s independent reasons to believe that extrinsic properties cannot end them (as they must if dispositional essentialism is true). Goff musters a few such reasons, all to the effect that the fundamental properties of reality being extrinsic would entail craziness.
At this point it’s worth stepping back to review the various possibilities. It must be confessed that a world in which all the fundamental properties are extrinsic would be a strange one indeed. All sorts of toothy metaphysical problems would no doubt emerge, in particular to do with what this picture of fundamental properties implies about fundamental entities. One tactic might be to say that strictly speaking there are no fundamental entities, that at bottom all there is is relations without relata. Another might be to argue that the fundamental entities necessarily come as multitude, and are inconceivable alone. Still another might be to argue that the fundamental entities are conceivable independently of their having any properties—intrinsic or extrinsic—at all. Or perhaps we could just give up on dispositional essentialism altogether (and pure physicalism with it), and believe that at bottom reality is composed of fundamental entities with intrinsic properties.
I think the more jaded among us could be forgiven for speculating that this way lies a game of whose intuition is the least weird, the winner of which will be whoever can keep the straightest face while swearing blind that everyone else is talking nonsense while they make perfect sense. At any rate, I won’t pursue this line of thought any further here. I want to turn now to another take on all this, which seems to me to be far more promising.
Let’s return to the problem of regress in chains of analysis. The reasoning went that properties are analysed in terms of other properties, so if the resulting chains ever come to an end then there must be such things as fundamental, i.e. unanalysable properties. Picking it apart a little, we can see that this argument comes in two stages. A property, referred to by the predicate P, is defined by a new predicate, Q. Another such definition must be provided of Q, and so on. If these chains come to an end in a complete picture of fundamental reality, then the first cautious conclusion to be drawn is just that such a picture must contain primitive predicates, that is, predicates which cannot be defined non-vacuously in terms of others. To then reach the next conclusion—that reality contains fundamental properties—the further premise must be supplied that these primitive predicates will function in the complete picture by (truthfully) attributing properties. The rest of this post will be devoted to exploring what happens when this further premise is resisted.
To deny that primitive predicates attribute properties is just to hold that they function by doing something else. A predicate that often gets accused of this kind of non-attributive function is the truth predicate, which will serve as an illuminating example. The grimness of the prospects for finding a general definition of truth finds support from two directions. On the one hand, the common sensical correspondence theory of truth is difficult to unpack in a non-vacuous way (a fairly dated way of stating the correspondence theory is to say that a proposition is true if and only if it corresponds to a fact, but what is a fact if not a true proposition?). On the other hand, the Tarski equivalence (“p” is true if and only if p) seems to make clear that any definition of truth that fails to block the inconsistency of asserting a proposition’s truth while denying the proposition (such as that a proposition is true just when it is useful to believe, or when it coheres with other beliefs) has changed the subject.
But even if the truth predicate can’t be defined, perhaps something can be said about how it functions. The Tarski equivalence may not provide a definition, but it does (to pinch a phrase of Donald Davidson’s) represent our best intuitions about how the truth predicate is used. A lesson to draw from it could be that to say of a proposition that it is true is the same as to assert it. So rather than attributing a property to a proposition, perhaps the truth predicate functions by conveying the speaker’s belief in it—its function is expressive rather than attributive.
Now, it’s very difficult to imagine that the primitive predicates in a physical theory—in present theory these are things like having such and such an electrical charge, or spin, etc.—could be given an expressive treatment along similar lines, but the truth example does illustrate that property attribution may not be the only line of work available to a predicate. But what other options might there be, if neither attribution nor expression is appropriate?
One possibility, I would suggest, is that the function of primitive descriptive predicates is in an important sense null—devoid of any substantial content. Or, to put it another way, that being a primitive predicate is an important functional role in itself, independently of whether it does something else in addition, like attribute a property or express a belief. I have in mind that primitive predicates function like the simple pieces or tokens in a board game. In chess, for example, there’s nothing more to the concept of a ‘pawn’ than how it can be moved and what happens if it gets to the other end. (Well, there are some norms governing how it should look, but these are inessential to the game itself. If we had enough physical pieces we could permute all their roles, so that the front row was lined with queens, the rook moved diagonally, the object was to project the bishop, etc., and we’d still be playing chess, albeit in a very strange way.) Similarly, a primitive predicate can be thought of as having no semantic content aside from what other sentences it implies when predicated of a term. There is no additional need for it to be thought of as referring to a property out there in the world.
(To make a brief comment which ties in with the earlier discussion, there is no reason why the primitive predicates as they’re envisioned here couldn’t all be ‘extrinsic’, i.e. have an arity greater than one. In axiomatic set theory, for example, the only primitive predicate is a predicate relating two terms, usually symbolised as ∈, where “x ∈ y” is interpreted as true just when the set x is interpreted as referring to is a member of the set y is interpreted as referring to.)
Now, it may be objected at this point that the picture being drawn here—in which the primitive predicates are not ‘hooked on’ to fundamental properties—is going to lead to an implausible arbitrariness at the level of the whole system. To return to truth for a moment, if we assume that the expressive theory sketched above is more or less right, and that so is the classical theory of knowledge as being justified true belief, then the only difference between my saying of Jim that he is justified in believing that the Magna Carta was signed in 1215, and my saying of Jim that he knows that the Magna Carta was signed in 1215, is just that in the latter case I am additionally expressing my belief that the Magna Carta was signed in 1215. If this is the case then there is no fact of the matter about whether someone knows something or not. Knowledge is not an objective feature of the world, it is an ‘internal’ feature of human linguistic practice. In like fashion, the expressive function of truth will be inherited by any other concept whose definition or analysis it participates in.
Similarly, if primitive predicates in physical theory don’t hook on to properties, then neither will those that they participate in defining, directly or indirectly. And that’s everything, because these are the predicates which ground any and every chain of analysis. And if the web of theory doesn’t ‘hook on’ anywhere, what’s to stop it being completely arbitrary?
Responding to this objection will help clarify the picture. First let it be admitted that, according to this picture, ‘physical theory’ is indeed a massively holistic system. Since the meaning of a predicate is exhausted by what it implies when predicated of various terms, the meaning of any given predicate is dependent on all the others (sometimes directly, more often indirectly). No doubt there is also going to be a degree of contingency in the way the system is set up. Just as in a formalised logic only a couple of primitive operators are needed to define all the others (e.g. and and or can be defined from not and implies, or not and and can be taken as primitive and implies and or defined from them), there will probably be some degree of choice available as to which predicates are taken as primitive. What matters is the patterns of entailment between theoretical statements, not anything intrinsic to the predicates themselves (such as what outside the linguistic system they refer to), so long as there are at least some which are primitive. Which ones these are may change as theory is refined and expanded, with what were previously primitive predicates succumbing to analysis in terms of new ones which then serve as their explanans.
But for all its contingency such a system need not be arbitrary, and the reason—it’s time to bang this old drum again, I’m afraid—is that the system as a whole, its construction and its modification, is constrained by various requirements of utility. The requirement that physical theory succeeds at predicting and controlling the environment—in a word, that it succeeds in dealing with it—mean that the world with which physical theory deals provides endless conditioning stimuli upon it. Its logical structure needn’t be any more arbitrary than the internal structure of a neural net that has been trained for pattern recognition. Like the neural net, there may be different internal structures that could perform the same task, and so long as they perform it equally well there may be no grounds to prefer any particular one of them. It may even be the case that through such utility-conditioning the logical structure of physical theory begins to mimic the structure of the world, in which case maybe we could begin tentatively to link predicates with real properties, though these links would now be mediated by the utility of the system as a whole and would carry no air of ontological necessity. Or to look at it a different way, perhaps the lesson we would draw would be that the very concept of a ‘property’ is parasitic on the syntactic functioning of predicates. Thus we could give up a bit of realism about properties, recognising them as products of language and not keystones of reality out there in the world, and just go back to talking about them as we were before. Except now we’d have no need to worry about their ontology.
The picture I’ve sketched in the second half of this post is by no means original, and owes a hell of a lot to both Quine’s ‘web of belief’ and Robert Brandom’s inferentialism, both of which I’ve been on kind of a trip with recently. But in the name of returning to some of the considerations that kicked off this great rambling hog of a post, what sort of a picture is it that has been sketched? Is it of a kind with what Goff calls pure physicalism? Not quite. It’s not that someone who subscribes to this picture would necessarily disagree that we should look to and only to the physical sciences to find out what reality is like, or even that a completed physics would give us the fundamental picture of reality. But they might feel queasy about the metaphysical seriousness suggested by this wording. It may be that physics will provide a unified theory, and it may be that once it has there will simply be nothing left to say about fundamental reality. But the next inference—the claim that this unified theory gives us the fundamental picture of reality—is likely to provoke interpretive quibbling.
If this isn’t pure physicalism, then let’s give it a name: pragmatic physicalism. I’ve portrayed pragmatic physicalism as stemming from a suspicion towards the inference from a unified theory containing primitive predicates to the world containing fundamental properties. The consequence is a large-scale inversion in the conception of the way physical theory relates to the world it theorises about. Direct reference of predicates in physical theory to properties in the world gets displaced in favour of the utility of the whole system, and returns only in an indirect and contingent sense. But what reasons might there be for making this inversion?
One thought, which I shall end with, is that making utility the master concept is exactly what we might expect of someone who is looking to take a naturalistic approach not just to the various things that humans talk about, like God and the Good, but to human linguistic practices as such. As one animal among many, humans and human language are the result of evolutionary processes, and so it makes sense for someone on this path to treat language first and foremost as something humans do things with. And insofar as it is something things are done with, the relevant consideration is how successful it has been at doing those things. Is this not then the natural direction of slide for all those liable to sign up for either of the positions Goff was quoted as describing at the beginning of this post? Is pragmatic physicalism not the place pure physicalism will find itself once it has followed its own rationale all the way to the bottom?