The Real Paths to Ecocivilisation: Chapter 5: Mind and Cosmos: Nagel’s Challenge
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Thomas Nagel’s 2012 book Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False shines a powerful spotlight on a critically important part of the coming paradigm shift. Nagel is forensically searching for the most naturalistic answers available once materialism and physicalism have been rejected on logical-conceptual grounds, which, if you believe he is right, makes him the most important defender of naturalism of our time. Materialism is on its way to the dustbin of failed ideas, but there are always going to be people inclined towards skepticism and naturalism. In Mind and Cosmos Nagel tentatively feels his way towards a philosophical position that those people may hold in a society fit for ecocivilisation. The goal is a new, comprehensive world picture based on the hard sciences, and “the completeness in principle of an explanation of everything in the universe through their unification”. This world picture must take into account the failure of materialism. Nagel quotes Steven Weinberg’s Dreams of a Final Theory (1992) in support of the claim that, as things stand, reductive materialism is widely assumed to be the only serious possibility, and then assures his readers that the everyday operation of the hard sciences is not threatened by what is to come. But if we accept that materialism must be wrong, where do we go from there? Could any other unified theory take its place? Nagel states a preference for neutral monism and sets out in search of a new sort of naturalism.
This chapter is the most technical part of this book, and it may seem like we’re delving very deeply into arcane, intricate details, considering that we set out in search of a bigger picture. However, these particular details are needed in order to understand how this piece of the puzzle fits together with the piece supplied by Henry Stapp in Mindful Universe, which is covered in Appendix Two.
The rest of this chapter is a summary of Nagel’s book.
<Chapter 1> (Introduction)
If materialism is false then the physical, chemical and biological processes of evolution must all be reconceived in light of the fact that they have produced conscious organisms. Nagel raises two questions. Firstly, what is the probability of abiogenesis happening solely through the operation of the laws of physics and chemistry? Secondly, what is the probability that a viable sequence of genetic mutations should have occurred that was sufficient to permit natural selection to produce the organisms that actually exist? My own view is that these probabilities are currently completely unknowable because we only have a single example upon which to base our estimates. Nagel is similarly skeptical of the current paradigm’s ability to answer either question, though he stresses that within the scientific community it is the first that causes most concern. His skepticism is not based on religious belief, or upon the availability of a better option, but an intuitive feeling that the prevailing scientific account of evolutionary history doesn’t ring true and, given that the only thing supporting it is an assumption he has rejected, he sees no reason why he should believe it. For a materialist, it can be difficult to understand what Nagel is expressing here. If you believe materialism is true then the mainstream scientific account of abiogenesis is something you just have to accept, regardless of the level of improbability it involves. If it is the only serious option, then if it seems incredibly improbable then that must either be because it only seems incredibly improbable, but actually isn’t, or because something incredibly improbable just happened to happen. However, if the assumption of materialism is dropped then other options become available.
He then makes a bold suggestion: that there are principles of the growth of order that are in their logical form teleological rather than mechanistic. Teleology is going to be an important concept from here onwards. It comes from the Greek word “telos”, meaning “end”, “purpose” or “goal” and refers to a kind of causal process or order. A teleological process is one that is directed by its goal. We can think of mechanistic physical causality as “pushing” the world from its current state to future states, whereas teleology “pulls” it towards a specific end point. Aristotle’s physics, which was a central component of the dominant Western cosmological paradigm for two millennia, is teleological. According to Aristotle, the cosmos is made of four basic elements: Earth, Water, Air and Fire. These elements are continually trying to return to their natural positions – that is why a rock sinks in water, why water runs downhill, and why fire reaches upwards.
In the Newtonian physics that replaced Aristotle’s, the whole of the future is fully determined by the laws of physics, which leaves no scope for teleology, but the same does not apply in a world governed by the laws of quantum physics. It is physically possible that the quantum dice are loaded in favour of specific outcomes in a way that is scientifically undetectable. Perhaps you were destined to meet your spouse, and the universe conspired to make it happen. This is mysterious to say the least, but if there is no divine intelligence directing the process, then perhaps it could be categorised as naturalistic. Nagel acknowledges that proposing a teleological naturalism will strike many people as outrageous. This, he says, is because “almost everyone in our secular culture has been browbeaten into regarding the reductive research program as sacrosanct, on the ground that anything else would not be science.” People who challenge the old paradigm can expect to be condemned as cranks.
He then outlines the conditions of his project. Firstly it must be antireductionist. Secondly we must reject the idea that an incredibly improbable thing just happened to happen. If we are to “pretend to a real understanding of the world” then we are going to have to do better than that. Thirdly, we should be aiming for a description of a single natural order that unifies everything on the basis of a set of common elements and principles. Though we can’t expect to reach that goal any time soon, we should aspire to it. Cartesian dualism rejects that aspiration by abandoning the attempt at unification, while materialism and idealism are both failed attempts. Interventionist theism also fails to deliver this sort of unification, because it involves something that interferes with the natural order from outside.
We are looking for a new sort of natural order: one that includes mind. This new paradigm will necessarily include a historical component – we can’t just add mind as an afterthought at the end. The appearance of mind “casts its shadow back over the entire process and the constituents and principles on which the process depends.” If the process was teleological then the teleology must reach all the way back to the beginning, not just of life on Earth but of the whole cosmos.
How can we integrate this perspective with that of the physical sciences, as they have been developed for a mindless universe? In the old paradigm there is a hierarchy of hard sciences – biology is reduced to chemistry, and chemistry is reduced to physics. To what extent will this reductive system survive in the new paradigm?
Nagel then pays his respects to intelligent design theorists Michael Behe and Stephen Meyer, who have raised problems with the orthodox scientific consensus that Nagel thinks should have been taken more seriously by the scientific establishment than they were (a claim that did not go down well in some quarters). While their positive arguments in favour of an intelligent designer can be effectively resisted, their negative arguments against the prevailing scientific view should still be regarded as open, because the present paradigm rests strongly on assumptions that govern the scientific project rather than a well-confirmed hypothesis. However, Nagel can’t bring himself to believe that intelligent design is a credible explanation for the origin and evolution of life or that divine purpose is a likely explanation for anything else in the cosmos either.
The old paradigm is ripe for displacement. However...
“To argue, as I will, that there is a lot it can’t explain is not to offer an alternative. But the recognition of those limits is a precondition of looking for alternatives, or at least of being open to their possibility. And it may mean that some directions of pursuit of the materialist form of explanation will come to be seen as dead ends. If the appearance of conscious organisms in the world is due to principles of development that are not derived from the timeless laws of physics, that may be a reason for pessimism about purely chemical explanations for the origin of life as well.”
Chapter 2: Antireductionism and the natural order
The second chapter explores the conflict between scientific naturalism and antireductionism. On one side is the hope that the natural sciences can eventually account for everything, and on the other there are serious doubts about whether things like consciousness, intentionality, meaning, purpose, thought and value can be accommodated in the natural sciences. Nagel refers to the sides as “materialism” and “antireductionism”.
Not all materialists describe themselves as reductionist. However, from the perspective of people who have concluded that it is untenable, all attempts to accommodate consciousness within materialism suffer from the same problem: they are attempts to reduce the true extent of reality to a common basis that is not rich enough for the purpose. The resistance to the old paradigm can therefore be brought together under the name “antireductionism”, even though it cannot be united under any new one. If reduction fails then a limit to physical science has been revealed, and something will be needed to account for whatever is missing. In fact it may be even worse than this – if consciousness itself can’t be reduced to physics, then it is possible that some of the things associated with it, such as value and meaning, may also require a new sort of explanation.
If consciousness is not merely physical then it can’t be fully explained by physics. It follows that “aspects of our physical constitution that bring consciousness with them” can’t be explained by physics either. In other words, whatever it is about brains that allows their owners to be conscious, although physical facts themselves, will necessarily defy a complete physical explanation. If evolutionary biology cannot be fully reduced to physics, then it cannot account for the appearance of consciousness or any other phenomena that defy reduction. Therefore if consciousness is a product of biological evolution – if conscious organisms are an integral part of nature rather than miraculous anomalies – then we must be looking for a very different conception of the natural order to the materialistic one. Consciousness must play some sort of central role.
The antireductionist resistance to the old paradigm can’t remain negative forever. At some point a new paradigm must be assembled. At the very least we need to rethink naturalism, the consequences of which are currently poorly understood but potentially enormous. The reductionist programs are partly driven by the lack of any comprehensive alternative, and Mind and Cosmos is an investigation of the consequences of rejecting it. Materialism must be replaced. If we are to make sense of the natural world then we must start out from a larger conception of what has to be understood than materialism can offer. And we surely must commit to the search for an intelligible underlying order to the universe – a search that predates science by at least 2,000 years. We shouldn’t (and clearly won’t) just give up. However, it is not clear that everything can be made intelligible in terms of natural science. Maybe we need other forms of understanding.
It can seem that once you accept that reductionism has failed, the only way forward involves “adding peculiar extra ingredients like qualia, meanings, intentions, values, reasons, beliefs and desires to the otherwise magnificently unified mathematical order of the physical universe”, but this does not satisfy the desire for a coherent, generalised new understanding. It’s too ad-hoc. It is the opposite of elegant, and that is partly why it is insufficiently convincing to sustain a paradigm shift. Materialistic reductionism is partly motivated by the unacceptability of denying the reality of consciousness, but if we accept that this strategy has failed then materialistic naturalism is not just “false around the edges”. Perhaps the natural order is not just physical. Or even worse, perhaps there isn’t any comprehensive natural order where everything hangs together. Maybe there are only disconnected forms of understanding.
The intelligibility of the natural order
Assuming that there actually is a comprehensible natural order, what explains it? One answer is that the natural order is itself where explanation ends. Maybe we reach a point where we must say “This is just how things are”. Nagel is not disposed to see the success of science in this way. He thinks science should be seen as “part of the deepest explanation of why things are as they are”. When we prefer one explanation over another, it is not merely an aesthetic judgement. Rather, we believe the preferable explanation is more likely to be true.
Nagel considers rational intelligibility to be the foundation of the natural order. He thinks that the intelligibility of the world is not accidental, and this makes consciousness doubly related to the natural order. Nature gave rise to conscious beings, and it is (we hope) intelligible to those beings. “Ultimately, therefore, such beings should be comprehensible to themselves.” These are “fundamental features of the universe, not byproducts of contingent developments whose true explanation is given in terms that do not make reference to mind.”
The question of to what way or ways the world is intelligible looms over the whole of both science and philosophy. How much of the world’s intelligibility consists in its subsumability under naturalism – under “universal, mathematically formulable laws governing the spatio-temporal order”? If science has limits, are there any other forms of understanding that can render intelligible what science cannot? Before tackling this question, he takes a look at the old paradigm’s way of thinking: that science has no limits.
If there really are no limits, then the sort of intelligibility that makes science possible must be included in the final explanation. The materialist picture must therefore be extended to include an explanation, such that eventually “the physical intelligibility of the world close[s] over itself”. The existence of beings to whom the world is scientifically intelligible must itself be scientifically intelligible.
The story goes like this, Nagel says:
“The history of human knowledge justifies the belief that the only way to truly understand the natural order is through physical law. For the universe to be intelligible, everything that happens must be explainable in terms of those laws, at least in principle. We admit that we can’t currently grasp it, but that is because it is too complex, so we are going to need more specialised forms of understanding for practical purposes. But we can still attempt to discover universal principles and laws which govern the things from which everything is composed, and which the observable material world is a manifestation. These we call the laws of physics. We are therefore looking for the most systematic possible description of a material universe extended in space and time.
Though it is physics and chemistry which have proved most spectacularly successful in this quest for understanding, the greatest single leap forward towards a complete understanding was the theory of evolution, later enriched with the discovery of DNA. Neo-Darwinism offers a general means of subsuming the picture of the existence and developmental history of life as just another consequence of the equations of modern physics. Even if consciousness is proving to be a very stubborn loose end, it is possible to speculate that abiogenesis and evolution are just a very complex manifestation of entirely physical principles. The complex cognitive abilities that allow humans to understand not just science, but morality and art, can be explained by evolutionary psychology ('humans invented religion to bolster group cohesion', 'our appreciation of beauty evolved to allow us to judge health of potential mates', etc...). Surely it is reasonable to expect this sort of an explanation can be extended to cover all of our cognitive capacities.”
Nagel finds it puzzling how the above view should be so widely viewed as self-evident. There is an enormous amount that we don’t currently know or understand, but scientific naturalists claim they already know what the form of future progress will be. They believe their way of looking at reality is the pinnacle of human thought, and that a future theory of everything is at least potentially within their reach. But, argues Nagel, “so long as the basic laws themselves are not necessary truths, the question remains why those laws hold. But perhaps part of the appeal of this conception is that if the laws are simple enough, we can come to rest with them and be content to say that this is just how things are. After all, what is the alternative?
That really is my question.”
The weakness of theistic explanations
Nagel then contrasts theism and materialism as polar opposites in terms of explanation. For theists, all things begin and end with the intention of the divine mind (i.e. God’s will). Theism has often been associated with the ontological position opposed to materialism – idealism. This reverses the materialistic position, by making physical law a consequence of mind and ultimately interprets intelligibility in terms of God’s intention or purpose. This leaves the process of explanation and understanding as incomplete as a purely materialistic account. However, theism is of interest even to atheists, because it at least attempts to explain things that do not seem explainable by physical science. The inadequacies of the old paradigm seem to be real. If mind must be found a central place in our understanding of reality, isn’t idealism the obvious answer? Theistic idealism embraces this idea. Again, Nagel just isn’t convinced. It’s too far for his imagination to stretch and seems to him an unpromising way forward. Idealism is not the same as theism, of course. There have been atheistic idealists, such as Arthur Schopenhauer (1788-1860).
Finding theism no more credible than materialism, Nagel is interested in what lies between them. They do have something important in common: both theism and materialism are attempts to understand ourselves from outside our own point of view (transcendence), even though they use very different resources to do so. What justifies this common ambition of transcendence? Isn’t it enough to understand the world from our own viewpoint? Apparently not, because the ambition is irresistible. We seem to instinctively seek a worldview large enough to encompass itself.In terms of knowledge, both theism and naturalism try to justify our reliance on cognition to understand the world. At one extreme is Descartes, who argued that God would not systematically deceive us and therefore our reason should be infallible, and at the other is naturalistic epistemology, which argues that natural selection wouldn’t provide us with unreliable cognitive faculties. Neither of these schemes provides an effective defence against the skeptical conclusion that we are brains in vats. Neither justifies the ambition of transcendence.
But perhaps a more modest and realistic ambition is achievable – not an unassailably secure foundation to knowledge, but a way of understanding ourselves that isn’t self-undermining and does not require us to deny the obvious. That is to find a plausible account of the cosmos and our place in it, and neither theism nor naturalistic reductionism can deliver this more modest goal. Theism manages to admit the reality of more of what is so evidently the case, but even filled out with the doctrines of particular religions it only offers a partial explanation of our place in the world. It amounts to the claim that everything hangs together because of intention or purpose, without explaining how that intention operates. This leads us to a well known theological problem.
“An intentional agent must be thought of as having aims it sees as good, so the aims cannot be arbitrary; a theistic explanation will inevitably bring in some idea of value, and a particular religion can make this much more specific, though it poses the famous problem of evil.”
The importance of the problem of evil cannot be overstated. For many atheists the biggest single reason why they don’t believe in an Abrahamic God is the state of the world. If there is a God in charge of this unholy mess then it must be either incompetent or sadistic. Free will provides a partial defence – surely a world where humans have the freedom to commit evil is better than a world where everything is orchestrated by God and bad things never happen. Would you want to live in such a world? I think this argument is a good one, though it has historically caused additional theological problems because it implies that God cannot have perfect knowledge of the future. But the biggest problem, at least in the present context, is the difficulty of explaining why God would have willed into existence things like earthquakes, cancer and parasites.
Theological explanations do not offer a comprehensive account of the natural order. They do not even attempt to offer comprehensive intelligibility from within the natural order – why should we be able to fully understand God’s intentions? Theists are in part motivated by a belief that there is no possibility that brute facts such as abiogenesis can depend on nothing but the laws of physics, but theism isn’t the only possible response to this belief. Maybe a completely different type of systematic account of nature is possible.
In search of a coherent, comprehensive naturalistic explanation
Naturalistic theories suffer from a different problem. Instead of offering explanations that are insufficient because they come from outside, the explanations they offer from the inside are “not reassuring enough”. Too much rests on evolutionary psychology. “Mechanisms of belief formation that have selective advantage in the everyday struggle for existence do not warrant our confidence in the construction of theoretical accounts of the world as a whole.” Nagel then qualifies this – he says that the evolutionary hypothesis for the full range of our cognitive powerscould be reliable, but “we do not have the kind of reason to rely on them that we ordinarily take ourselves to have in using them directly – as we do in science.” This is “even more clearly true of our moral and other normative capacities” (“normative” refers to the rules that define “normal” behaviour). “Evolutionary naturalism implies that we shouldn’t take any of our convictions seriously, including the scientific world picture on which evolutionary naturalism itself depends.”
Nagel promises to defend these claims in later chapters (see Chapters 4 to 6 below), but right now he has a simpler point: even if evolutionary naturalism fails to provide a transcendent self-understanding, we should not abandon the search. There is no reason to believe that our confidence in what we have concluded are objective truths (not just about science, but also about morality) is dependent on the assumption that our cognitive capacities are the product of natural selection. Evolutionary psychology is too weak a ground for that. Our confidence in the truth of certain propositions should not be so easily shaken – and can’t be shaken “without a kind of false consciousness”.
Nagel then re-iterates his opposition to simply giving up on the hope for transcendent understanding, even though such a view has had distinguished adherents. Here he mentions Wittgenstein’s rejection of metaphysics as a proper task of philosophy, and he rejects this attempt to close off the transcendent ambition.
“To refrain we would have to believe that the quest for a single reality is an illusion, because there are many kinds of truth and many kinds of thought, and they cannot be systematically combined though a conception of a single world in which all truth is grounded. That is as radical a claim as any of the alternatives.”
The question does not go away, regardless of whether or not we attempt to answer it. Even if we accept that the materialistic account of ourselves is false, it remains the case that we are the products of the long history of the universe since the big bang, descended from bacteria over billions of years of natural selection. That is part of the true understanding we are in search of, so our question is how to combine this with all the other things we know, in a coherent worldview that does not undermine itself. Somehow the world produces conscious beings capable of doing all that we do, including evaluating evidence for competing hypotheses about the natural order. Even if we don’t know how this happens, it is hard not to believe that some sort of systemic explanation is possible.
Nagel then explains his idea of a satisfactory solution.
“The inescapable fact that has to be accommodated in any complete conception of the universe is that the appearance of living organisms has eventually given rise to consciousness, perception, desire, action and the formation of both beliefs and intentions on the basis of reasons. If all this has a natural explanation, the possibilities were inherent in the universe long before there was life, and inherent in early life long before the appearance of animals. A satisfying explanation would show that the realization of these possibilities was not vanishingly improbable but a significant likelihood given the laws of nature and the composition of the universe. It would reveal mind and reason as basic aspects of a nonmaterialistic natural order.”
In this passage Nagel seems to be joining mind and reason – consciousness and intelligence – together in a way that will make them difficult to untangle later. He has explained his motive: he does not like the idea of separating consciousness itself from what appear to be higher-order manifestations of consciousness. He is in search of a unified naturalistic worldview, so he is trying to bring more than just the basic phenomenon of consciousness under an umbrella, where he hopes we might begin to assemble a systematic post-materialistic naturalism. Nagel is not convinced that evolutionary psychology will be enough to explain the full range of our cognitive powers, and is suggesting that the teleology that was necessary for the evolution of conscious organisms is also the most plausible explanation for the ongoing evolution of our cognitive capacities.
Chapter Two ends with the assessment that all we can do at this stage in the history of science is to argue for recognition of the problem; we’re still a long way from solutions.
Chapter 3: Consciousness
If we take seriously the problem consciousness poses to a comprehensive naturalism then it threatens to unravel the entire naturalistic world picture, but we aren’t exactly awash with viable alternatives. Modern naturalism began with Galileo and Descartes, both of whom divided reality into the world of matter, which could be precisely described mathematically, and mind, which could not. For them... “it was essential to leave out or subtract subjective appearances and the human mind – as well as human intentions and purposes – from the physical world in order to permit this powerful but austere spatiotemporal conception of objective physical reality to develop.” That this would eventually be challenged is inevitable, because humans can’t repress the desire for a unified world picture. Our bodies are part of the physical world and our minds are strongly connected with, and probably strictly dependent upon, physical events in our brain, as well as causal connections between our bodies and the rest of the world. It is this connection that has encouraged the hope of including the mind in a single physical conception of the world. This is recent; Descartes thought it was impossible. There has always been resistance to dualism, but for several centuries after Descartes this was mostly expressed through idealism. By the later 20th century this had been replaced, at least in analytic philosophy, by attempts to unify starting from the physical. Physics is assumed to be philosophically unproblematic, and the Cartesian ghost in the machine is the main target. An alternative is therefore required, and here began a series of failures.
Several versions of behaviourism failed for the same reason: they were verificationist. They attempted to reduce consciousness to what can be observed from the outside, which cannot be done because consciousness is what is inside. They all left out the most essential character of consciousness, which is subjectivity itself. Behaviourism was followed by identity theory (as a scientific theory) – mental events “are” physical events in the brain. But what is it about mental events that makes them also physical events? It must be something conceptually distinct from the physical properties that define brain activity, because without that it becomes a conceptual rather than scientific truth (declaring brain activity to be identical to brain activity gets us nowhere). Materialists don’t want to give a dualistic answer – that consciousness is brain activity because it has non-physical properties in addition to its physiological ones. But they have to give some answer, and it has to be consistent with materialism, which necessarily pulls them back into some sort of behaviourism: “What makes the brain process a mental process, they proposed, is not an additional intrinsic property but a relational one – a relation to physical behaviour.” The identity theorists had to explain how “pain” and “brain state” can refer to the same thing even though their meaning is not the same, and do so without appealing to anything non-physical in accounting for the reference of “pain”. This led to the positions known as causal behaviourism and functionalism, as well as more complicated positions down the same path, all of which fail for the same old reason: they clearly leave out something essential, without which there is no mind. And the thing they leave out is exactly the same thing that Galileo and Descartes deliberately excluded at the dawn of modern science.
An additional problem was noticed by Saul Kripke. Identity theory is based on the idea of other identities such as “H20 = water” or “heat = molecular motion”. Kripke argued that these identities are necessary truths, even though they aren’t conceptual or a priori. Water is nothing but H20 – you can’t have H20 without water, and you need nothing more. These arescientifically discovered identities, and they are true regardless of whether there is anybody around to be conscious of it. What makes this proposed identity necessary? “Experience of taste seems to be something extra, contingently related to the brain state – something produced rather than constituted by the brain state. So it cannot be identical to the brain state in the way water is identical to H20.”
Many materialists involuntarily wobble between saying “consciousness is brain activity” and “consciousness is produced by brain activity”, unaware that they are doing it, and unable to stop. They need the first statement to defend materialism, but it doesn’t make any sense, because consciousness is very obviously not identical to brain activity. The second statement makes sense, but it implies something other than materialism.
The mind-body problem is sufficiently difficult that we should now expect theoretical progress in this area to require a major conceptual revolution. The broader naturalistic program, at least in its current form, cannot survive the failure of psycho-physical reductionism. Many philosophers of mind are still committed to it – they see the difficulties as problems that can be solved. Nagel asks these people to see the rest of his argument as hypothetical – it is about what the consequences would be if we rule out reductionism. And the consequences run deep: materialistic naturalism is untenable, even as an account of the physical world (because humans are part of it). This goes a long way to explaining how “costly a position antireductionism in the philosophy of mind is”. Much is at stake. This is no regular paradigm shift.
The double mystery in need of explanation
The appearance of consciousness still needs to be explained, as part of the larger project of making sense of the world, and evolution must be part of this explanation. What kind of explanation of the development of conscious animals – even one that includes evolution – could account for the appearance of organisms that are not onlyphysically adapted to the environment but also conscious subjects? It can’t be a purely physical theory.
“What has to be explained is not just the lacing of organic life with tincture of qualia but the coming into existence of subjective individual points of view – a type of existence logically distinct from anything describable by the physical sciences alone.”
The appearance of consciousness can’t be a separate question to the appearance of conscious organisms. The whole thing has to be explained, and make sense. The materialistic version of evolution cannot be the whole truth – it is not an accident that humans and other animals are conscious, so we need an explanation of their mental character as well as their physical character. Materialism can’t even account for everything in the material world, because it can’t account for humans. On a purely materialist understanding of biology, consciousness must be a tremendous and inexplicable extra brute fact about the world – and since no such inexplicable brute facts belong in a comprehensive vision of the natural order, something fundamental has to give. Antireductionism allows us to pose the question of what it is.
Conscious animals are the result of biological evolution, but however well-supported is this empirical fact, it is not an explanation: it does not provide understanding, or enable us to see why the result was expected or how it came about. An explanation based on physical reproductive fitness will not be enough.
“Selection for physical reproductive fitness may have resulted in the appearance of organisms that are in fact conscious, and that have the observable variety of different specific kinds of consciousness, but there is no physical explanation of why this is so – nor any other kind of explanation that we know of..... ….a postmaterialist theory would have to offer a unified explanation of how the physical and the mental characteristics of organisms developed together, and it would have to do so not just by adding a clause to the effect that the mental comes along with the physical as a bonus. The need for an illuminating explanation of the mental outcome pushes back to impose itself on the understanding of the entire process that led to that outcome.”
In other words, we can’t just say “natural selection did it.” For that explanation to illuminate in the way we expect scientific explanations to illuminate – especially evolutionary explanations – we need to explain the role of consciousness in all this. What sort of organisms are conscious? What was the difference between the first conscious organism and its last unconscious ancestor? Did it happen in a single generation? If not, when did it start happening, and why? How did consciousness affect the behaviour of those first conscious organisms? Why didn’t evolution produce zombie animals? As things stand, there is not even the beginning of a scientific answer to any of these questions. Either no answer is available at all, or there are plenty of suggestions for answers but none of them are particularly well supported or offer much hope of a breakthrough. This what an inadequate paradigm looks like. How can we scientifically explain consciousness, given that, from our present scientific perspective we have no idea what purpose it serves or when in evolutionary history it appeared?
Nagel then rejects “outright dualism”, since this too would abandon a hope for explanation: substance dualism entails that biology has no responsibility for explaining the existence of minds. He is interested in the alternative hypothesis that biological evolution is in some way responsible for the existence of consciousness, but because consciousness defies physical explanation this means we must revise our view of evolution.
If we accept that evolution is not purely physical, how much do we need to add to produce an explanation of consciousness that makes the appearance of conscious organisms intelligible? This is a crucial question. Nagel says we need to be looking for the following:
(1) At least in later stages, consciousness plays an essential role in survival.
(2) The relevant features of consciousness are genetically transmitted.
(3) Genetic variation supplies the candidates for natural selection, which, at least after a certain point, is simultaneously mental and physical variation.
(4) (And most significantly) these mechanisms should be preceded by others in the earlier stages of evolution that created the conditions for their possibility.
“This would mean abandoning the standard assumption that evolution is driven by exclusively physical causes. Indeed, it suggests that the explanation may have to be something more than physical all the way down. The rejection of psycho-physical reductionism leaves us with a mystery of the most basic kind about the natural order – a mystery whose avoidance is one of the primary motives of reductionism. It is a double mystery: first, about the relation between the physical and the mental in each individual instance, and second, about how the evolutionary explanation of the development of physical organisms can be transformed into a psycho-physical explanation of how consciousness developed.”
We are in search of two parts of an explanation, corresponding to the double mystery described above. The historical account (how conscious organisms evolved) presumably depends partly on the constitutive account (the mind-brain relationship). Our goal is to replace these two deep mysteries with a single intelligible explanation.
The constitutive question
For the mind-brain relationship the possibilities are either reductive or emergent. A reductive account will explain consciousness in terms of the properties of its elementary parts, which means conscious beings must have non-physical constituent parts. There is potential for great confusion here. “Reductionism” usually refers specifically to reduction to the physical, but “reductionist” is also a description of a theory that reduces everything to mind, or to the neutral stuff of neutral monism. When Nagel talks about a reductive constitutive account, he’s talking in this more general sense, that a theory reduces whatever it is trying to explain to the fundamental constituents of reality, whatever they are. And since we are composed of the same stuff as the rest of the universe, it would seem to follow that a reductive constitutive account will involve some sort of panpsychism.
An emergent account would have to link consciousness with brain processes specifically, and so does not lead to panpsychism. Nagel isn’t interested in the emergent account, and neither am I. Emergence only makes sense if whatever is required to produce the thing that is emerging can be found in the basic constituents of whatever it is emerging from. Without this you’ve just got inexplicable magic, and that is not going to fly if what we’re after is intelligibility. We should therefore eliminate the emergent constitutive option from our enquiries, and that means we must take seriously the reductive alternative: we are searching for an answer that accounts for the relation between mind and brain in terms of something more basic about the natural order. If such an account is possible, it would explain the appearance of consciousness in animals by means of a general monism, according to which the constituents of the universe have properties that explain not only its physical but its mental character.
He then quotes Tom Sorell:
“Even if the mechanisms that produced biological life, including consciousness, are, at some level, the same as those that operate in the evolution of the physical universe, it does not follow that those mechanisms are physical just because physical evolution preceded biological evolution. Perhaps some transphysical and transmental concept is required to capture both mechanisms. This conjecture stakes out a territory for something sometimes called 'neutral monism' in addition to dualist, materialist, and idealist positions.”
In other words, if neutral monism is true then there is nothing intrinsically impossible about explaining how conscious biological life evolved. Consciousness could already have been there, embedded in the fabric of reality, right from the start. In this case, consciousness is not an effect of brain processes – “rather those brain processes are in themselves more than physical, and the incompleteness of the physical description of the world is exemplified by the incompleteness of their purely physical description.”
The historical question
For the explanation of how consciousness evolved there are three options: causal (appealing only to law-governed efficient causation), intentional, and teleological. A causal account is one where the process consists entirely of “pushing” by natural physical causality. A teleological account is one where the process is also “pulled” by a goal. An intentional account involves divine will and intellect.
For theists, the intentional historical account is the obvious answer. It raises all manner of other questions, especially concerning the problem of evil, but it is an option to answer the question at hand. However, since we are searching for a new naturalistic paradigm, or at least the closest we can get, “God did it” can’t be the answer until such time as all others have conclusively failed. We can therefore rule out the intentional account (at least for now).
What about the causal historical (and constitutively reductive) account? This leads us back to panpsychism again, and this time Nagel doubts that it can make sense: “The protopsychic properties of all matter, on such a view, are postulated solely because they are needed to explain the appearance of consciousness at high levels of organic complexity. Apart from that, nothing is known about them: they are completely indescribable and have no predictable local effects, in contrast to the physical properties of electrons and protons, which allow them to be detected individually.”
We have no idea how such an explanation might work, and there’s no obvious way to make progress on it. It also still leaves us with the question of how the first conscious organism evolved. How can the same principles apply both before and after that moment? This class of theory doesn’t offer us much in the way of intelligibility either. In this respect, is it even an improvement on emergence or materialism? The reductive teleological explanation is now the only non-theological option still standing. This, Nagel admits, looks like a throwback to Aristotle, but he’s convinced it is coherent, that it is quite different to the theological answer, and that it should not be ruled out. I must admit that I’m not sure how different they really are, at least in the absence of an alternative explanation for the teleology apart from the will of God. The only clear difference is that the theological explanation is that God did it whereas Nagel’s explanation ends with teleology itself: teleology did it.
What sort of teleology?
Of the six initial options (two kinds of constitutive account times three kinds of historical account) the constitutively reductive and historically teleological explanation stands out as the most promising. Emergence is unintelligible, leaving us with the three reductive historical options. We’ve rejected the intentional historical account because it’s theological, which leaves us a choice between the causal and teleological accounts. Of these two, the causal account sets up several different apparently unanswerable questions, whereas the teleological account sets up just one: What explains the teleology?
What we are really looking for is a solution whereby the constitutive account dovetails with the historical account: an explanation for the relationship between consciousness and brains that somehow naturally leads to a teleological explanation of the origin of conscious life. And perhaps, if we find the right answer, it will shed some light on certain other mysteries that have been lingering around the edges of science like bad smells.
Nagel then strengthens his claim that the theory we should be searching for must be universal, and not a process that is unique to the appearance of conscious organisms:
“[I]t is essential, if teleology is to form a part of a revised natural order, that its laws should be genuinely universal and not just the description of a single goal-seeking process. Since we are acquainted with only one instance of the appearance and evolution of life, we lack a basis for bringing it under universal teleological laws, unless teleological principles can be found operating consistently at much lower levels. But there would have to be such laws for teleology to genuinely explain anything.”
This quote is important. Nagel thinks we should be looking for teleological laws – and even says that there can be no genuine teleological explanation without them. He also is saying that in order for a new paradigm to be naturalistic then the process that led to the appearance of the first conscious organisms cannot have been unique. If it was then we are not going to be able to construct a new model of the natural order, because one unique process doesn’t give us enough to work with, even if that process was itself natural. We will need to find other examples of teleological processes that are amenable to scientific investigation, and laws that govern them, universally and consistently.
Nagel then clarifies something about his proposed teleology. Teleological explanations are typically associated with the idea that outcomes have value, so that it is not arbitrary that those particular teleological principles hold. This leads in turn to the question of whether value can be understood independently of the purposes of some conscious being.
“Nonpurposive teleology would either have to be value-free or would have to say that the value of certain outcomes can itself explain why the laws hold. In either case, natural teleology would mean the universe is rationally governed in more than one way – not only through universal quantitative laws of physics that underlie efficient causation but also through principles which imply that things happen because they are on a path that leads towards certain outcomes – notably the existence of living, and ultimately conscious organisms.”
So we are looking for a sort of teleology where either the goal needs no value, or where the value of that goal can itself explain the teleology. Nagel is not hopeful about approaching such a theory directly. He thinks it will need to be done in stages. Firstly we need to fix the conceptual problems, and then there will presumably be a lot of scientific work to be done. Maybe we lack crucial information about the brain.
Chapters 4 to 6
Nagel now moves to a new topic – that of intentionality. He defines this as “the capacity of the mind to represent the world and its own aims” and notes that it is more controversial to claim that intentionality can’t be explained materialistically than it is to claim that consciousness can’t be explained. However, he’s convinced that intentionality, thought and action will also resist psycho-physical reduction, and this is what the remainder of his book is about. “I believe that the role of consciousness in the survival of organisms is inseparable from intentionality: inseparable from perception, belief, desire, and action, and finally from reason. The generation of the entire mental structure would have to be explained by basic principles, if it is recognized as part of the natural order.”Philosophy can’t generate such explanations – it can only “point out the gaping lack of them, and the obstacles to constructing them out of presently available materials.”
Is consciousness separable from reason? Nagel seems to think it is not. I am not so sure. Consciousness and intelligence are certainly linked in humans, but we have no reason to think AIs are conscious and good reason to suspect that even animals as simple as earthworms may well be conscious even though they are incapable of anything but the most basic sort of reason. The capacity for reason implies some sort of complex structure that processes information, but the distinction between a conscious worm and a zombie worm could well be binary – surely either there is an awareness of something, or there isn’t.
He now asks whether our cognitive capacities could be placed in the framework of an evolutionary theory that is no longer exclusively materialist, but retains the Darwinian structure. There are two aspects. The first is how likely it is that natural selection should have produced creatures of our cognitive capacity, able to extend our knowledge vastly beyond initial appearances (he gives the examples of science, logic and ethics). Is it credible that selection for fitness in the prehistoric past should have fixed capacities that are effective in theoretical pursuits that were unimaginable at the time? The second is understanding naturalistically “the faculty of reason that is the essence of these activities.”
First he points out that the question doesn’t even make sense if there isn’t an objective reality to find out about. On an anti-realist view there is no possibility of finding truths – either scientific or moral – in an external world. He then states that anti-realism about moral truths is a more serious option than for the scientific case. Nagel is a moral realist – he doesn’t just believe there is an objective reality out there, but that there are true/false answers to at least some moral questions that are theoretically accessible to any rational being. The opposite to moral realism is moral anti-realism, including moral subjectivism and relativism. This is a book about realism, and also about morality, and questions about the status of moral realism are indeed going to matter. Whether or not they matter in the current context is a different question. Nagel thinks they do.
He then provides an uncontroversial account of evolutionary psychology, which he skeptically describes as a “just so story”. At the end he acknowledges that “it is not easy to say how one might decide whether [our advanced cognitive capacities] could be a manifestation of abilities that have a survival value in prehistoric everyday life. In view of the mathematical sophistication of modern physical theories, it seems highly unlikely, but perhaps the claim could be defended.”This was the first part of Mind and Cosmos that surprised me; I think that claim is quite easy to defend. The human brain is extraordinarily adaptable. We are capable of learning all sorts of specific things which were unthinkable to early anatomically modern humans, from the invention of writing onwards.
This discussion would presumably be easier if we had some details – any idea at all – of how this proposed teleology worked in the primary example of the evolution of conscious life. Without that information it is almost as mysterious as other possibilities that we have already rejected as unpromising or unintelligible. As things stand, how can we even guess how likely it is that a general theory will be found, or what other sorts of processes might be relevant, or what teleological laws might look like? Nagel’s argument here concerns advanced cognition – especially the ability to escape from our subjective viewpoint and understand objective reality and abstract theories such as quantum mechanics. He then applies similar reasoning to our ability to make value judgements, such as our capacity for morality. He believes this should be considered as a third candidate for a teleological evolutionary explanation, suggesting that there is ongoing teleological evolution of our cognitive powers, at least with respect to value judgements. If true, this may have implications for our future capacity to build an ecocivilisation. Maybe we really aren’t the biologically finished article, and our path to ecocivilisation will be guided not just by the brutal mechanics of natural selection through a die-off and population bottleneck but by teleological upgrades to our ability to make value judgements.
The arguments about advanced cognition and value judgements lack the logical force of the argument with respect to consciousness – they rank among the easy problems of consciousness rather than the hard problem. However, Nagel thinks the universality they imply and their potential to contribute to a general theory justifies his belief that these things also have a teleological explanation.
Mind and Cosmos concludes with the following comments:
“I would like to extend the boundaries of what is not regarded as unthinkable, in the light of how little we really understand about the world. It would be an advance if the secular theoretical establishment, and the contemporary enlightened culture which it dominates could wean itself of [sic] the materialism and Darwinism of the gaps – to adapt one of its own pejorative tags. I have tried to show that this approach is incapable of providing an adequate account, either constitutive or historical, of our universe.
However, I am certain that my own attempt to explore alternatives is far too unimaginative. An understanding of the universe as basically prone to generate life and mind will probably require a much more radical departure from the familiar forms of naturalistic explanation than I am at present able to conceive. Specifically, in attempting to understand consciousness as a biological phenomenon, it is easy to forget how radical is the difference between the subjective and the objective, and fall into the error of thinking about the mental in terms taken from our ideas of physical events and processes. Wittgenstein was sensitive to this error, though his way of avoiding it through an exploration of the grammar of mental language seems to me plainly insufficient.”
“I would be willing to bet that the present right-thinking consensus will come to seem laughable in a generation or two – though of course it may be replaced by a new consensus that is just as invalid. The human will to believe is inexhaustible.”
Part Two of this book is my contribution to the exploration of what lies beyond the current boundaries of the thinkable.
[Back to contents][This book is available in print form.]