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Is physicalism an impoverished metaphysics?

Every so often, we read about some philosopher or other form of public intellectual who makes the claim that a physicalist ontology – a world view in which only things that can be described in terms of physics are said to exist – is impoverished. That is, there are things whereof science cannot know, &c. A recent example is that made by Thomas Nagel [nicely eviscerated here by the physicist Sean Carroll], whose fame in philosophy rests with an influential 1974 paper that there is something like being a bat that no amount of physics, physiology or other objective science could account for.

Recent, Nagel has argued that the evolutionary view called (historically misleadingly) neo-Darwinism, is “almost certainly” false. One of the reasons is that “materialism” (which Nagel should know is an antiquated world view replaced by physicalism defined above; there are many non-material things in physics, not least fields of various kinds) does not permit a full account of consciousness; the subjective facts of being a particular individual organism. Another is that the chance that life would emerge from a lifeless universe is staggeringly unlikely. How this is calculated is somewhat mysterious, given that at best we only have (dare I say it?) subjective estimates anyway, but there it is.

But Nagel is not alone. Various nonreligious (apparently) thinkers have made similar assertions, although some, like Frank Jackson, who proposed the Knowledge Argument, have since backed down. What is it that physicalism must account for that these disputants and objectors say it cannot?

It almost entirely consists of consciousness, intentions, intelligence or some similar mental property which is entirely inexplicable by “reductionist” physicalism. [Reductionism is a term of abuse that means – so far as I can tell – solely that the person who makes such an accusation does not like the thing or persons being accused.] And that raises our question: is physicalism lacking something?

What I have been waiting for since I tricked independently upon a physicalist view aged 16 or so, is a reason to think that this is the case. What was once defined as irreducible (to physics), such as the fluidity or water or the ability to make abstract maps of the world and then to navigate it with some success, have been shown merely to be a matter of computational tractability, not logical or metaphysical impossibility.

Consciousness in particular strikes me as a ghostly strawperson. When one is asked to define consciousness, if it is done functionally, then we can understand that there are purely physical systems (including computers of some kind) that can replicate these functions. If it is done in terms of the subjective experience, then as I have argued before, even a digital camera has some degree of subjectivity. But if it is done in terms of ineffable experience, one has to ask why something that cannot be expressed clearly can act as a counterexample to states of affairs that can be expressed clearly and precisely.

Something that is inexpressible cannot exclude (or deny the completeness of) states of affairs that can be expressed. We may feel like there is a “what-it-is-like” to be conscious, but this alone doesn’t give us any reason to think that state is anything more than simply being conscious; in other words, of having a cognitive location, nature and capacity. What it is like to be a bat is just to be a bat; what it is like to be a human being is just to be a human being, and so on, right down to what it is like to be me (or any other individual) is simply to be that individual.

The ineffable states of consciousness, the qualia as they are called, strike me as a mistake of language. Once, Ludwig Wittgenstein noted that “Philosophy is a battle against the bewitchment of our intelligence by means of our language.” (§ 109, Philosophical Investigations). Merely because we have such terms as “seems”, “feels” and phrases like “What-it-is-like” is no reason for us to conclude that there are seemings, (irreducible) feelings and qualia; to think so is to confuse verbs for nouns, or functional terms for ontologies. That we are conscious (that is, that we do things in a conscious fashion) is beyond reasonable doubt. That conscious behaviour implies Consciousness (the substance or ontologically irreducible state) is beyond credulity. We are being bewitched by our language.


One major consequence of taking our verbing language as nounish is that we then tend to privilege our consciousness as the primary state of the world. I don’t mean panpsychism, although that seems to me a prime example of this mistake, but the idea that the world we experience is a mere construct of our [language | mind | worldview | etc.], as if we make the world in which we live. This mistake is rife in post-Idealist philosophy, and is perhaps an error assigned to the early empiricists, who asserted that all we know and experience is the evidence of our senses, making our senses primary to the world being sensed. This is akin to making the letter primary to the letter-writer, and even the postman. It appears in the claim that if two people have very different worldviews they literally live in different worlds (a view ascribed with varying justice to Thomas Kuhn, Immanuel Kant, and even Wittgenstein himself).

Where two principles really do meet which cannot be reconciled with one another, then each man declares the other a fool and a heretic. [On Certainty, §611]

Kuhn’s idea of paradigm includes this mistake, and generations of philosophers have repeated it, as if all that two different scientists who hold theories that are not reconcilable held in common was that they had theories, and not (as Wittgenstein noted) a form of human life, a shared culture and the rest. But anyway, back to physicalism.

One of the main criticisms of physicalism is that it leaves unspecified which physics is taken to be all there is. This depends upon the assumption, often repeated by philosophers, that what there is can best be derived from a formalisation of some theory in a domain, and as physics covers all domains, it must have all the objects. I do not think this. For a start, an ideal and final physics is very unlikely to be developed any time soon; each time we have declared that we now have the standard model of this or that we find things that undercut or extend our conceptions (dark matter, dark energy, etc.). But deeper than this, I think that no matter what we finally conceptualise the world to be, it is likely not to be the only formal theory that can do this.

Again, we verb our nounings.  If we have a descriptive model of the universe in some representation, it may be that we have cut nature at the joints that interest us, but that some other beings might find unintuitive and maybe even incomprehensible. So I cannot think that I must assume that what exists in the world are all and only the objects that have classifications in some theory, no matter how accurate, precise and universal that theory might be.

Instead, though I think that whatever does exist will be describable in a physics if we can only investigate it. For instance, were it the case that qualia existed, then I would expect them to have some physical, causal effect on other objects, in ways that were regular and manipulable. If there is no causal effect, then I cannot think that class of things is real. Any kind of coincidental parallelism between qualia and brain states, for example, strikes me as a scientific, not to mention a metaphysical, miracle, and miracles are the enemy of understanding. So I don’t exclude qualia because they are not physical, but because if they are physical, they are mysterious and miraculous and uncausal.

So, what ontology should we expect to get from a physicalism, and where might the gaps be? I might leave that until another post…


  1. DiscoveredJoys DiscoveredJoys

    Tricky stuff, language. If, for instance, we were to say that physicalism was foundational, we could put an end to the grumblings about reductionism. Rather than deride people reducing ‘finer feelings’ to mere physics, we could just acknowledge that physics was foundational to fine feelings but not necessarily the complete explanation required.

    But in turn that would also require people (physicists, philosophers or theologians) to recognize that a great deal of what we prize (rationality, cognition, morals, souls) is constructed upon hidden layers of unconscious thought and emotion.

  2. I never know whether I completely agree with you or completely disagree with you. Are there things that science cannot know? Well, when I look around my library, I see an enormous number of books about things that science has nothing to say about. For example, what do physicists have to say about the emergence of the modern nation state? It’s not that the historians deny (or would deny if it ever came up) that Henry the Eighth or his associated particles didn’t obey the equations of quantum field theory, it’s just that this way of describing him and his activities is apparently irrelevant—as I believe you’ve pointed out yourself, reductionist arguments don’t really explain anything if they go down too many levels. And then there’s philology, art, music, stamp collecting, politics, hoping, fearing, dreaming, praising, thanking, designing, etc.

    Are there things that science cannot know? Yep. Practically everything, unless, of course, you simply define thing to mean the sort of thing the sciences are supposed to be able to address, at which point physicalism becomes a tautology. I’m reminded of a very old prejudice in philosophy, the notion that substance is the master category. It seems to me that science works precisely because it excludes from its purview almost everything in the universe, where everything is defined as the range of entities that people do or can take note of. The problem comes when the ideologists of Science with a capital S decide that what the scientists define as reality is, appearances to the contrary, the real reality. How is this postulation not just another one of the true worlds denounced by Nietzsche? Does it even help us explain what happens when me and my cohorts try to psych out intergranular stress corrosion cracking in stainless steel?

    That was the completely disagree part. The completely agree part is that the usual complaints against what you call physicalism are generally just another version of the true world bit. Reifying consciousness is a way of treating it as a strange sort of substance, a noun instead of a verb or (my preference) an adverb. If it ever does make sense to talk of qualia, it’s pretty clear that we shouldn’t be talking about pixels. Meanings have citizens rights in my view, but they are not substances. I am genuinely puzzled by the way in which debates about the true scope of science always turn out to be a way of attacking or defending some sort of theology or other instead of the disciplinary boundary dispute it ought to be.

  3. My problem with physicalism (and also with reductionism) is that it simply isn’t useful in many cases. Knowing that “everything is reducible to the physical” is of little use if I don’t know how to characterize the physical (as you touched upon, and is made most clear by Hempel’s dilemma) and if I don’t know what form that reduction takes (if I did then physics as practiced by us really would let us explain everything and we’d be done with the whole science thing). Now, if it was simply useless then I wouldn’t bother wasting my typing fingers on it, but it is worse than useful, in many cases it is stifling. In most context that physicalism or the ontology of current physics is brought up is to silence somebody else.

    This use of power is fine when the discussion is close to physics (say in chemistry) where we can have reasonable confidence that our current physics captures the relevant part of this magical ‘physical’ and where the reduction is at least plausible (although not fully spelled out; for instance in chemistry semi-classical models are used but we believe that they ‘reflect’ in an essential way the most important parts of a full quantum reduction). But in settings far from physics (like neuroscience and psychology) there is no reason to believe that by the time we find a reasonable reduction, the thing we are reducing to will resemble current physics. As such, when a physicst butts in with their uninformed opinion, they are seldom helpful. Now of course, we shouldn’t jump at this like Negel and build some crazy new ontology and argue that “this is really what the world is like”, but should instead take another quote from Wittgenstein: “What we cannot speak about we must pass over in silence.” Why erect a needless global ontology? Why not just have our own little ontologies for our sub-disciplines and maybe some partial dictionaries between them instead of pronouncing one ontology as the “one true word”. Why assume more certainty than we have reason for?

    Of course, this doesn’t mean that we can be willy-nilly and make up whatever we want, however we want. Even without physicalism as a grounding, one can be wrong and useless. Each area of science or even human experience more broadly, has its own standards for what is a reasonable ontology. A psychologist can dismiss the ontology of a psychic without needing to appeal to the authority of physics. The opposite of physicalism is not mysticism, just like the opposite of objectivism (which physicalism relies on) is not complete and utter subjectivism. One can walk a fine line between and embrace a plurality of methods without muffling those that offer alternative perspective.

    • DiscoveredJoys DiscoveredJoys

      But knowing that the physical is foundational to everything is useful. If you accept that there is only the physical then concepts and activities that include reliance on the supernatural can only have cultural value, not absolute value. If you argue that not everything can – in principle – be reduced to physics then you have to explain how additional ‘stuff’ works with physics, and why we have found no evidence yet that such ‘stuff’ also exists.

      So while I agree it is incredibly difficult to explain subjective experiences in terms of foundational physics, I can see the big steps from physics to peoples’ experience and look askance at any explanation that depends on non-physical elements. Unless anyone has proof, of course.

  4. Brian Brian

    Shorter version: The universe is causally closed?

  5. TomS TomS

    My problem is that I don’t understand what one is saying about something when they say it exists. Is there something unequivocal about saying that there is a solution to x^2=-1 and there are atoms and there is one game left to play and there is something unequivocal about …?

  6. Assuming that “only things that can be described in terms of physics are said to exist,” then what counts as a description in terms of physics? Is it enough to say that a theoretically possible but computationally intractable account is a “description in terms of physics”? Or must the account be both theoretically possible and computationally tractable?

    For example, I suppose it is theoretically possible to describe “in terms of physics” why radicals are beheading people for propaganda in the Middle East, or why the symphonies of Beethoven satisfy my ear more completely than do the symphonies of Brahms, or why it seems that I am exercising free will in deciding which examples to give here. But accounting for all of those things “in terms of physics” would be computationally intractable. And I suspect that such an account would also be explanatorily useless, mainly because those are matters in which human life and action are not carried out “in terms of physics,” but rather in the activities of, respectively, politics and war, poetry and music, and language and philosophy.

    Speaking of which, I wonder whether there could possibly be an account of the “terms of physics” in the terms of physics. Or, more generally, what is the account of mathematics “in the terms of physics”? Is there an explanation “in the terms of physics” by which we can determine that what rightly follows the symbols “1+1=” may be any of the symbols “2,” “12/6,” or “log 10 (100)” (or an infinite number of others) but not the symbols “3,” “12/4,” or “log 10 (1000)” (or a different infinite number of others)?

    Do we say, then, that the reasons for the recent beheadings, my preference in music, the sensation of free will, mathematics, or even “the terms of physics,” simply do not “exist”? If so, the can is only kicked a short way down the road: What is the description, in terms of physics, of those illusions? And more importantly, how is that description useful to someone endeavoring simply to live well?

    • TomS TomS

      Assuming that “only things that can be described in terms of physics are said to exist,” then what counts as a description in terms of physics?

      Do all things that can be described in terms of physics exist?

      Spin times momentum (or degrees Celsius per (angular) degree, and I’m sure that someone who is literate in physics can come up with a better example) is a description in terms of physics. Does spin times momentum exist?

      • Yes, there’s that, too. And what does it mean that quantum mechanics must be “interpreted”? Which part “exists”: the experimental result, the interpretation, or whatever ultimate reality underlies the result but is meaningless apart from the result and the interpretation?

    • Brian Brian

      Speaking of which, I wonder whether there could possibly be an account of the “terms of physics” in the terms of physics.

      This reminds me of the counter to Hume’s fork or logical empiricism. The response I give is that inductively, not deductively, we’ve not found a counter example. We’ve gleaned up examples and by induction have proposed a rule and as yet haven’t found anything that looks like a metaphorical black swan.

      Whether that response has any value, I don’t know. I’m a code monkey, not a philosopher. 🙂

      • “Code monkey” and “philosopher” aren’t mutually exclusive categories;
        I don’t see why you can’t be both.

        That the methods of physics continue to produce ever more accurate predictions of phenomena is a good excuse to keep doing physics. But it’s not much of an account for why physics has been so successful, or for why the expression of successful physics takes the particular (mathematical) form that it does.

        • Brian Brian

          Well, religion or ‘sprirituality’ is allowed to introduce mystery willy-nilly and have nothing to show for it regarding explanations of how the world works. Physics seems to reduce the mystery incrementally and I’m typing on something that quantum mechanics has furnished so I guess from an ‘instrumental point-of-view, its explanations of how the world works, work.

          As for an account of why physics is so successful or why mathematics of a certain form are used, that seems to me to be the anthropic principal. It your world is a certain way, then your explanation, if it tracks reality, will mirror (however obscurely) that world. I’m reminded of that Douglas Adams thing about the sentient puddle that assumed there was a reason behind the hole it was in fitting so perfectly. Of course, that may be too easy, to much of a cop-out.

          It’s not introducing new mystery saying it’s a brute fact that the universe is the way it is, and mathematics of a type just does prove useful. No ontological fecundity of say, the rainbow serpent did it and that maths was pleasing to it. Which is not to say that I think it’s a pointless question and/or I discourage smarter types from investigating it. I guess I’ve lived without knowing that over 40 years, and I think I’ll die long before there’s a satisfactory answer, if one is possible.

        • Just because some particular techniques have proven their fitness to the purposes of describing certain structures and predicting certain movements, even to the extent, perhaps, of expanding the domain where they can be profitably applied, that doesn’t mean those techniques or the assumptions underlying them are a “metaphysics,” “impoverished” or otherwise. And the fact that those techniques can yield persuasive demonstrations that the intuitions entailed by a “religious” or “spiritual” outlook are inconsistent with measured observations does not mean that the “physicalist” assumptions underlying those techniques are necessarily a replacement for the “metaphysics,” if any (“supernaturalism”?), that might be said to underlying the “religious” or “spiritual” outlook.

          In either case—of, say, “physicalism” or “supernaturalism”—people are just using the conceptual tools that they find to be useful for situating themselves or living well; they’re not attempting to posit a coherent “metaphysics.” That’s probably because a coherent metaphysics isn’t a precondition of situating oneself comfortably within the universe, or fitting a puddle to a hole in the ground, as the case may be. And it seems to me that’s one of the chief reasons why physics and the other sciences can be so successful: there is no need to bog them down in the morass of metaphysics. If every observation had to be traced back and grounded in metaphysical bedrock before integrating it into a useful theoretical structure, then the work of scientists would never get anywhere. That provisionality independent of metaphysical certainty is why we can do science.

          So it’s deeply ironic, I think, to see scientists now turning around and purporting to have established some new metaphysical certainty—it’s a little like watching somebody announce that by refusing to play baseball, and instead just examining the field, the equipment, and the players, they have at last discovered the true meaning of the game. It’s not that they have an “impoverished” version of baseball; they’re not playing it at all.

          Which is not to say that’s a bad thing; the quest for metaphysical certainty is probably a red herring. If that’s the case, then that ought to be the message from scientists, instead of “here is the certainty we came up with by abandoning a need for certainty.” 

  7. Not sure why my name on the prior comment is “Petereter.” It should just be “Peter.”

  8. LD LD

    Instead, though I think that whatever does exist will be describable in a physics if we can only investigate it.

    What counts as “a physics” or “a physical, causal effect”? My impression is that many physicists don’t understand causality as fundamental.

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