Thomas Nagel is a renowned contemporary American philosopher, born in Belgrade (modern-day Serbia) on July 4, 1937. Outside philosophical circles he is perhaps best known for his 1974 essay “What Is It Like to Be a Bat?” where he argues against the material/physical reductionist account of the mind and especially – of consciousness. This remains Nagel’s central position in the philosophy of mind – that mind, consciousness and subjective experience of being (what it is like to be X for X) cannot be fully explained by physical processes in the brain and body. There is a deeper underlying problem here – that of objective vs subjective approach. In other words, no matter how much we discover, observe and measure in and about a bat’s brain and body (objective approach), we will not be able to know how the bat experiences its own being (what it is like to be a bat for the bat, subjectively). Bat is only an example, of course. The same can be said of any other life form. Nagel’s latest book, “Mind and Cosmos”, elaborates on and presents his long-standing belief that physical reductionism is not a good enough account of reality. Not if that reality includes minds, as it, in fact, does.
Nagel gave a very bold subtitle to his 2012 “Mind and Cosmos” book: “Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False”. This immediately sets the tone for the entire book and makes the author’s position very clear. Namely, he rejects the universal validity of the widely accepted physical reductionism explanation of the natural order. Throughout the book, he refers to it mostly as naturalistic reductionism (or reductionist naturalism), but I will keep using physical reductionism in this article, as I feel it is a more precise description of the position he challenges. Nagel holds that such an explanation cannot give a satisfactory account of consciousness, mind, and moral realism that he supports (I touch upon each of them in this article). All of these phenomena are, for him, irreducible to purely physical, mechanistic and random processes. Therefore, since they are part of the natural order, any valid explanation of reality must include a satisfactory account of these phenomena as well. It is important to note at this point that Nagel does not suggest a theistic (for instance, intelligent design) account of the natural order. He is an atheist. In fact, he assumes that it might be the lack of alternative reasonable options of explaining the reality that adds to the all-too-easy acceptance of the physical reductionism account (because if not this, then the only alternative is a theistic explanation – so the assumption goes).
What is Nagel’s justification for holding such critical views of the prevailing explanation of the natural order? In his opinion, the conventional evolutionary theory contains many assumptions that lack direct evidence. In this context, he especially stresses the lack of scientific evidence to explain the origin of life on Earth. In addition, he is sceptical that evolution by natural selection based on accidental, fully random genetic variation alone can provide a satisfactory explanation of the entire history of evolution. Based on this lack of scientific evidence, reliance on general assumptions, and, for him, the existence of evidence that contradicts the orthodox theory (consciousness, mind, values that we all experience), Nagel considers his criticism is justified.
One crucial basic assumption that Nagel has and states it openly in his book is that we are justified in relying on our common-sense convictions about our cognitive capacities, self-consciousness and moral judgement. He believes that even the most fanciful scientific theory has to be compatible with our common-sense. Therefore, if something “flies in the face of common-sense”, as he puts it, we have a valid reason to doubt it. I would like to stress this point once again because it is fundamental to the entire case Nagel presents in this book. In other words, if I am less convinced about the universal reliability of our human common-sense and, furthermore, think that hardly any scientific development would be possible if ‘compatibility with common-sense’ was a mandatory condition, then I have good reasons to disagree with Nagel’s position. If I can present evidence that our common-sense is not at all as reliable as Nagel seems to fundamentally assume, then I can build a case to show that his argument is weak. This is something I will explore in a separate article, as Nagel is not the only contemporary philosopher who assumes the essential reliability of our common-sense and builds his argument on that foundation.
Back to the book – what goal does Nagel have in mind? This is pretty clear already from the start. He argues against physical reductionism as the only serious explanation of the natural order as a whole. Also, more broadly and, in my view, importantly, Nagel urges intellectual humility – namely, we should recognize the limitations of any of our methods in helping us achieve an understanding of everything. In other words, none of our theories or methods can in principle have unlimited explanatory power.
Nagel’s own philosophical project that he favours and presents in this book can be described as teleological metaphysical naturalism. What does it mean? Since Nagel is an atheist, he wants a naturalistic explanation of reality, without reference to the supernatural. However, in his view, there must be some elements of purposefulness in a successful theory of reality (hence, teleological – having a purpose – as opposed to purely random and mechanical). He does not propose a specific account of the natural order but he outlines the criteria that such a theory should satisfy. These are the three conditions that he considers crucial for developing a valid, comprehensive worldview:
- anti-reductionism (especially if this is physical reductionism),
- teleology – some things are so remarkable that we are justified in expecting a non-accidental, purpose-driven explanation (but not theological),
- a necessary aspiration towards discovering a single unifying natural order – but without the ambition for absolute certainty.
The structure of the book consists of an introduction and four chapters. In the first chapter, Nagel presents his argument against physical reductionism in the context of the natural order. He suggests that an expanded naturalistic form of an explanation is needed to account for consciousness, mind and reason as basic aspects of the natural order. He denies dualistic positions (that is, distinct mental and physical substances) as he is convinced we should strive for discovering a unified natural order. Also, he considers theistic approach insufficiently explanatory, as it tends to deny the obvious. For him, to say that things like our minds and consciousness are a form of divine intervention (theism) or should be accepted as brute facts (physical reductionism) is to effectively say that they are beyond explanation (or that there is, perhaps, nothing to explain). This is what he challenges.
Nagel expects that a satisfactory account of natural order would explain life and mind not as something accidental and improbable, but rather as a significant likelihood given the way the universe is. Such an explanation should be consistent with our common-sense confidence in our cognitive faculties and would support it instead of undermining it. He argues that the contemporary physical reductionism account actually undermines the reliability of our cognitive faculties. How can we be justified in relying on our cognitive abilities as we do, if we accept that they are a chance byproduct of mechanistic natural selection processes? Whatever answer you come up with, note that you will be using those same cognitive capacities to come up with it. So you have to assume their reliability in order to justify their reliability. That’s a vicious circle and is utterly incompatible with our common-sense beliefs. For Nagel, it’s a signal that there is something wrong with the explanatory theory if it produces such an undermining effect.
In the following three chapters, Nagel elaborates on the main examples of what he considers serious obstacles to a physical reductionism worldview – consciousness, cognition/mind, and value, respectively.
Consciousness: Nagel’s position on consciousness is that
a) it exists (as supported by our common-sense beliefs), and
b) physical sciences cannot account for it, so
c) physical description of the world can only be a part of the entire truth.
For Nagel, since we have consciousness and are part of the natural world, any tenable explanation of the natural order has to account both for its physical and mental character – in one, as it is one reality. He considers that mental phenomenon such as consciousness calls for an explanation because it represents regularities, patterns. When we recognize such patterns we understand that there must be something that renders them intelligible. Simple causation by the processes of the brain is not a satisfactory explanation. Nagel considers that a full explanation must demonstrate what it is about evolution that makes both physical and mental history a likely probability. Generally, he sees two options of possible explanation theories – reductive (but not necessarily only physical reductionism) or emergent. As far as consciousness is concerned, he prefers the reductive approach but only as long as the basic parts of the universe are not just physical but also mental in nature. He calls it “neutral monism”.
Cognition/mind: Nagel assumes that such higher-level cognitive capacities as they are manifested in humans can only be possessed by conscious beings (so, consciousness is a mandatory precondition and thereby AI is excluded). This he takes as a signal that such capacities cannot be understood by physical sciences alone. His main question in this chapter is – how to understand nature as a system capable of generating mind and reason? Unlike with consciousness, Nagel holds some variation of emergent explanation for the mind as more likely. Consciousness could be present in the fabric of reality but reason, being a higher-order complexity, is more likely to emerge from certain preconditions. That would mean that the evolutionary history would have to contain an explanation of the appearance of reason. Nagel thinks such an explanation would have to include a teleological element – the potential for mind and reason being inherent in the natural order and evolution moving in that direction.
Value: Nagel holds a moral realism position (values being objectively real, not just subjective in my mind) and, therefore, considers it problematic to make it compatible with the orthodox evolutionary theory. He links the appearance of value with the appearance of life. Therefore, evolutionary theory should be expanded to account for the development of beings that are capable of discovering the moral truths which do not depend on the preexisting beliefs of those beings. Nevertheless, while he considers value to be real, it is still life-form specific. So, human values are not the same as those of lions, for instance. It is clear, therefore, that also value can best be explained by some variation of emergent account since it does not exist before life and appears together with life. The next step in the development happens when the life-form starts to recognize the moral truths.
Here we have reached the end of the book and, unsurprisingly, of its review. Thank you for sticking around this long, I hope you found it interesting. At this point, I would like to wrap my article up by using Nagel’s poetical metaphor in which he sums up his preference for a teleological account of the natural order:
“The universe is waking up and becoming aware of itself.”Nagel, 2012