Philosopher of science Peter Vickers puts forward his take on the recent IAI News standoff between panpsychism and idealism.
It is absolutely accepted that the philosopher should have a great respect for science, as an epistemological endeavour. On the face of it, both science and philosophy search for truth: scientists ask ‘big’ questions such as “Where did human beings ultimately come from?”, and philosophers similarly ask ‘big’ questions such as “What is the relationship between the mind and the brain?”. But whereas scientists sometimes actually reach truth (human beings evolved from more primitive mammals, which themselves evolved from amphibians, etc.), philosophers seemingly never do, and are doomed to forever go round in circles.
Looking back at the history of philosophy, it is usual to speak of ‘fashions’; for example, when we ask about the relationship between mind and matter, there was a time when dualism was in fashion, a time when idealism was in fashion, and another time when physicalism was in fashion. More recently, panpsychism is enjoying a great deal of attention. But it would be bold indeed to claim that philosophers are on the way to definitively solving the mind-matter problem, in the way scientists have definitively solved a huge number of epistemological problems. Of course, some Kuhnians would try to push back, saying that science is punctuated by revolutions. But this is a fallacy: only radicals on the fringe think the evolutionary theory of mankind’s origins will one day be overturned in a Kuhnian revolution. Similarly, scientists really do know where stars come from, how viruses and bacteria cause illness, and a hundred other things. (Open questions concerning the details remain, naturally.)
In light of this thought, what should we make of the recent debate between Philip Goff and Bernado Kastrup, concerning the mind-matter problem and the nature of consciousness? Two solutions are offered: panpsychism (‘mind is everywhere’), and idealism (‘everything is mind’). Even before we look at the arguments, it seems clear that these can only be suggestions, or hypotheses. What we find is that the two authors sometimes state explicitly that we ought to believe in their favoured proposal. But given that these are philosophical proposals this seems like an exaggeration. Whilst it might be agreed that – considered in isolation – there are some quite persuasive philosophical arguments for Goff’s panpsychism, or Kastrup’s idealism, we must always bear in mind that the very nature of the evidence for these proposals is the kind of evidence that, historically, has never been able to definitely establish something as a ‘fact’. Consider, for example, arguments for panpsychism appealing to ‘simplicity’.
Two solutions are offered: panpsychism and idealism. Even before we look at the arguments, it seems clear that these can only be suggestions.
This isn’t to say that there is an absolutely clear dividing line between what might be called ‘philosophical evidence’, and scientific evidence; scientists, in addition to experiments and observations, also make use of arguments akin to philosophical arguments, for example. Sometimes they even appeal to ‘simplicity’. So we should think of a spectrum, running from ‘fully scientific’ evidence on the one extreme, through to ‘fully philosophical’ evidence on the other extreme, with a substantial grey area in the middle. The crucial point is this: when one tries to place the evidence put forward for panpsychism and idealism on this spectrum, it certainly comes much closer to the ‘fully philosophical’ end of the spectrum. And that makes it ill-suited to settling a dispute.
This is one problem with debates concerning the mind-matter problem and the nature of consciousness: sometimes protagonists overstate the strength of the evidence in favour of their own proposal. However, this is a relatively benign indiscretion. The critical thinker can carefully distinguish between arguments and rhetoric, ignoring a protagonist’s own, personal, and inevitably biased judgement of the overall weight of evidence. And the best scholars will try hard to be appropriately modest, epistemically speaking. A good example is Goff’s statement that, “There’s a good chance that none of the theories currently being proposed are correct.”
There is a second, more serious indiscretion, though. This is when the philosopher asks us to take seriously a proposal that goes strongly against established scientific opinion. In the extreme case, the philosopher asks us to take seriously a proposal which contradicts scientific consensus. This is rare, and is very much frowned upon in academic circles. More common is a situation where we are asked to take seriously a proposal that is in tension with a strong scientific consensus (it doesn’t actually contradict the relevant scientific claims, but it sits next to them rather awkwardly). On the face of it, the proposals of both Goff and Kastrup are cases in point. Goff’s panpsychism asks us to take seriously the idea that “a revolution is coming”, where science is turned on its head, and human consciousness can be explained by the fact that microscopic material things quite generally have some kind of very basic, ‘primitive’ consciousness. Kastrup’s idealism is even more revolutionary, and would no doubt be repugnant to the vast majority of practicing scientists: for Kastrup, the electron itself is an immaterial idea, an aspect of mind. It all sounds very unscientific, and even ‘new age’. New Agers sometimes argue that the Earth is conscious, for example.
Goff and Kastrup would no doubt insist that their proposals are not really in tension with established scientific ‘facts’. For example, Kastrup might argue – invoking the spirit of Bishop George Berkeley – that everything scientists say about protons, neutrons, and electrons is still true; it’s just that really these are truths concerning aspects of mentality, or consciousness. So, Kastrup would agree that electrons have a negative charge, but how we unpack and interpret that fact is now thoroughly re-imagined. Indeed, Kastrup often plays the science card, insisting that his proposal takes scientific results more seriously than most, and that this is a significant virtue of his idealism in comparison with other philosophies of mind. For example, in a debate with Goff he argues that “analytic idealism is not only consistent with both microphysics and neuroscience, it even helps to make sense of a number of their observations”, and he claims that it is more consistent with science than Goff’s panpsychism. He stresses that his idealism is especially sensitive to “concrete, verifiable, empirical facts, such as dissociation” (original emphasis).
This is one problem with debates concerning the mind-matter problem and the nature of consciousness: sometimes protagonists overstate the strength of the evidence in favour of their own proposal.
Elsewhere, however, Kastrup's presentation of the science seems significantly biased towards his idealism. At the very least the presentation is not neutral. In a 2019 Scientific American article he favours one particular interpretation of quantum mechanics – Relational Quantum Mechanics – and even states that this particular interpretation has recently been ‘verified’ by physicists. The truth is, this interpretation remains a minority interpretation, and it is not the case that it has been experimentally supported in a way other interpretations of quantum mechanics have not been. In another article Kastrup (together with his co-authors) once again presents the science in a potentially misleading way. The authors reference some recent scientific experiments and write, “these experiments indicate that the everyday world we perceive does not exist until observed”. But the experimental results are fully compatible with the three most popular interpretations of quantum mechanics (GRW, Bohm, and Everett), all of which account for quantum phenomena via the assumption that the everyday world does exist prior to being observed. As the article proceeds, a serious potential to mislead persists, in particular when it is stated that, “QM seems to imply that the world is essentially mental”, and “According to QM, the world exists only as a cloud of simultaneous, overlapping possibilities”. These statements are incorrect, or at least very much biased. To the vast majority of relevant thinkers, QM does not imply that the world is essentially mental; that is just one (minority) view.
To what extent is Goff’s panpsychism in tension with scientific consensus? As with Kastrup, Goff would agree that everything scientists say about protons, neutrons, and electrons is true. After all, physics ultimately focuses on what matter does, as Goff has repeatedly stressed. The ‘quantum spin’ of the electron is to be cashed out in terms of the behaviour of electrons in certain experiments, such as Stern-Gerlach experiments. The intrinsic nature of spin is something physics is silent on, and necessarily so – the methods of physics can never penetrate to such ontological depths. If physics is silent on it, the philosopher can say just about anything about it whilst remaining consistent with physics. Goff makes use of this to develop panpsychism, along with its central payoff: the promise of a genuine solution to the hard problem of consciousness. If some incredibly primitive form of consciousness is an intrinsic feature of matter generally (including elementary particles), then the hard problem of consciousness suddenly looks considerably less hard: complex human consciousness exists because the matter brains are composed of is itself primitively conscious, in its intrinsic nature.
How controversial is this proposal? In a quite serious survey of philosophers, physicalism about the mind came out clearly on top. And it is probably reasonable to say that scientists working in fundamental physics, neuroscience, etc., are even more likely to be broadly-speaking ‘physicalists’ than philosophers are; they certainly reject dualism, and physicalism (“there is only the physical”) is commonly seen as the only reasonable alternative. Thus – even without conducting a survey of relevant scientists – I suggest that there is a solid scientific consensus in favour of physicalism. And this entails quite a solid scientific consensus against panpsychism. Thus, in a sense, panpsychism contradicts – or is at least in serious tension with – a strong scientific consensus. Given that science trumps philosophy, as an epistemological pursuit, doesn’t this mean that it is irrational, or unreasonable, to believe in panpsychism?
But this doesn’t work as an argument. Whilst science does indeed trump philosophy as an epistemological pursuit, a consensus amongst scientists does not entail that there is actually any scientific evidence for the view in question. It isn’t science that has brought about the consensus amongst scientists vis-à-vis physicalism about the mind. When one asks a scientist for an opinion on the mind-matter debate, the scientist in that moment is acting as a philosopher. There isn’t any evidence at the ‘fully scientific’ end of the evidence spectrum in favour of physicalism. The mind-matter debate is a philosophical debate, after all. Scientists may well have a (firm) view on a philosophical debate, but that doesn’t entail that there is any scientific evidence backing up their opinion. The fact that they are scientists doesn’t mean they are acting as scientists, in that moment: ‘what science says’ and ‘what scientists say’ need to be clearly distinguished.
The real problem with opposing a scientific consensus comes not when there is mere consensus opinion, but when a consensus has been built upon a platform of (fully) scientific evidence. Thus it is totally unreasonable to oppose the extremely strong scientific consensus on the cause of Covid-19, for example. But when it comes to panpsychism, it isn’t clear that there is any real opposition to the relevant kind of scientific consensus. Goff sometimes talks of the need for a ‘scientific revolution’ – a “new science of consciousness” – where we put qualities back in the world. But he might do better – rhetorically speaking – to emphasise just how much contemporary science would stay fully intact in the ‘revolution’ he imagines. Indeed, whilst panpsychism does indeed call for a quite dramatic adjustment of worldview (for most of us, at least!) it doesn’t overturn any properly scientific claims.
The fact that they are scientists doesn’t mean they are acting as scientists, in that moment: ‘what science says’ and ‘what scientists say’ need to be clearly distinguished.
To illustrate, consider the question whether a tree falling in a wood, with no one there to hear it, makes a sound. According to Goff, Galileo gave the definitive scientific answer to this question back in the 17th century. The falling tree does not make a sound, because all it really does is set up a sound wave within the particles in the wood. When we zoom in on the wave we find no sound at all – all we find are air particles moving around in a kind of pattern. We only call it a sound wave because it presents to our consciousness as sound when it enters our ears and sends a message up the auditory nerve to the brain. But when nobody is there, in the wood, there is no sound at all – there are only particles moving around. This is the modern scientific viewpoint: we don’t hear the sound of a crashing tree because that very sound is out there in the external world, waiting for us to hear it. We only hear the sound of the crashing tree because that’s how our brain – when appropriately stimulated – chooses to present the relevant information to us. The wood itself remains silent as the tree crashes down.
Would Goff disagree with this? At first it seems that he definitely would disagree. His latest book is entitled “Galileo’s Error”, and the book is advertised on YouTube using the tree-falling-in-a-wood example. The advert stresses that Galileo would say ‘No’, the falling tree doesn’t make a sound. When I first saw this advert, I was sure that the point of the advert was that on the panpsychist account the answer is ‘Yes’. But I was wrong – the answer for the Goffian panpsychist is still ‘No’, in complete agreement with Galileo. Thus Goff’s panpsychist fully agrees with the definitive scientific answer – whatever Galileo was in error about, it wasn’t this!
This may initially seem surprising. However, whilst Goff wants to put real qualities into the external world, he doesn’t want to put the very qualities we experience (back) into the external world. So Goff doesn’t want to say that ‘real sound’ is out there waiting for us to hear it, nor that ‘real colour’ is out there on the surfaces of strawberries and blades of grass. The qualities that are out there in the external world are (almost certainly) not like the qualities we experience. The sound and the colour we experience are properties of our brains when those brains are in a particular state. In the case of sound, our brain is put into the appropriate state whenever the compression waves we call ‘sound waves’ enter our ears and get processed, in precisely the way scientists would describe.
Whilst panpsychism does indeed call for a quite dramatic adjustment of worldview it doesn’t overturn any properly scientific claims.
If the panpsychist worldview doesn’t disagree with any properly scientific claims, why is it so controversial? Many scientists – keen to stress the importance of experiments and falsifiability – would say that panpsychism is pure speculation, and there is no good reason to believe it. Now, if we’re being careful, there are reasons to believe it, but (as noted already) the reasons are ‘philosophical’ and so of limited persuasive power. An interesting option for Goff now arises: instead of arguing that we ought to believe panpsychism, he might argue that panpsychism is no less likely than the physicalist alternative most scientists embrace, given that the evidence (such as it is) for the physicalist alternative is also at the ‘philosophical’ end of the evidence spectrum. In other words, panpsychism shouldn’t be anywhere near as controversial as it is within the scientific community. After all, there is no scientific evidence concerning the intrinsic properties of elementary particles. There is only scientific evidence concerning what these particles do, and all of that is retained on the Goffian view. It is just as speculative to assert that those intrinsic properties are not ‘mental’ in nature as it is to assert that they are somehow ‘mental’. The truth is, we really can’t say.
It is valuable for scientists to be nuanced about what precisely their scientific evidence does and doesn’t establish, and where science ends and philosophy starts. Scientists can certainly have strong instincts concerning issues where they don’t have any (or much) properly-scientific evidence. In such cases it is easy to conflate the concept of a scientific consensus where you merely mean that the vast majority of scientists agree, and the concept of a scientific consensus where properly scientific activity has led to community agreement. These are very different things and, when it comes to physicalism, the former is in play, not the latter. In the case of the mind-matter debate I can’t help but wonder whether, if panpsychism didn’t have such a reputation for being in tension with science, and if scientists were better educated on the hard problem of consciousness and the panpsychist (partial) solution to it, there mightn’t be a greater balance of opinions within the scientific community. Such a balance of opinions is something Goff could aim for, not by arguing that we ought to believe panpsychism, but by arguing that we ought not to be so sure about any of the alternatives, including physicalism.
On our request, the original post of this article on 01 Dec has been amended by the author to clarify his interpretation of Bernardo Kastrup’s presentation of some of the scientific ideas referred to within the article. We will be inviting Philip Goff and Bernardo Kastrup to reply here.
We have also changed our original subtitle of “Can radical theories of mind be considered scientific?” to the current one from Peter Vickers.
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