If you are like me, you probably have a bunch of books that you bought somewhere at sometime for some reason but still have yet to read. For me these books always seem like something I want to read at the time but, for various reasons, I barely crack them open before they move to a pile then later to a shelf mostly unread. That’s the case for me with The Mystery of Consciousness by John R. Searle (1997). The book is largely a reprint of book reviews Searle wrote for the New York York Review of Books. My paperback copy of the book has a cartoonish man on the cover with a third eye in the middle of the forehead. Looking for something else in my double stacked shelves, I ran into the Mystery again and decided to pull it off the shelf, to place it near my nightstand.. Since the book is compact, it immediately attracted my attention placed near a pair of mammoth tomes which I also desire to read someday but don’t quite have the energy or inclination to read now. They may too migrate to the shelves to be rediscovered one day.
Mystery was something of a surprise to me. The book covers many of the big hitters in consciousness academia at the time of its publication: Crick, Edelman, Dennett, Chalmers, and Rosenfield (maybe not so big a hitter but interesting nevertheless) with others like Ned Block, Churchland, and Nagel mentioned a lot in passing. It not only explains the positions of each of them in concise and readable prose but it also shows the problem of each of their positions. Several chapters have an addendum with other information including exchanges with Dennett and Chalmers. The book is over twenty years old but the arguments seem still current. Searle’s refutations and objections are on the mark. Maybe I’ve discovered I’m a Searlean because so much of what he writes seems straightforward, obvious, and almost commonsensical.
To clear up one thing right away – Searle is not arguing that consciousness is a mystery. What he is arguing is that many people – even philosophers – think it is a mystery but for Searle it is a scientific and primarily biological problem. The objective of the book is to move beyond mystery to science. Searle agrees consciousness is produced by neurons firing in the brain. The scientific problem is figuring out how neurons firing in the brain generate a subjective experience that is so completely unlike the underlying physical phenomena that are producing the experience.
Early in the book Searle address one of the seemingly obligatory explanations required for a book on consciousness. He explains what he means by consciousness:
“consciousness” refers to those states of sentience and awareness that typically begin when we awake from dreamless sleep and continue until we fall asleep again at night, or fall into a coma or die or otherwise become “unconscious”… Consciousness so defined is an inner, first person , qualitative phenomenon. Humans and higher animals are obviously conscious but we do not know how far down the phylogenetic scale consciousness extends. (p. 5)
Even though Searle can’t avoid the use of terms that tightly relate to or imply what he is defining (sentience, awareness) , he does make a useful contrast with sleep and coma in his definition. Sleep and coma are states about which we have no memory. While Searle doesn’t draw directly the conclusion that consciousness is related to memory, his definition would seem to imply that consciousness is a state in which we could potentially form memories. Consciousness for Searle is either on or off but it can vary in intensity from drowsy to full awareness with the boundaries being states of which we can have no memory. More about this later when we discuss Edelman and Rosenfield.
In Searle’s accounting, consciousness is real, not an illusion. In his review of Dennett’s Conscious Explained, he invites the reader to a small experiment of pinching the skin on the forearm. What happens, of course, are a bunch of reactions in physical sensory neurons, the spinal cord, and the brain that culminates in a unpleasant sensation on the skin of the forearm. This resultant feeling is qualitative and subjective. It is known only to you. Its mode of existence is first person. The description of the reactions of neurons and in the brain is third-person objective. The feeling of unpleasantness is real and is what science must explain.
Searle begins with Crick. He finds Crick’s Astonishing Hypothesis an excellent book for its explanations of neuroscience but finds the author himself “badly advised philosophically.”
There are different ways of spelling out [the argument for the irreducibility of consciousness] but the fundamental point is the same: the sheer qualitative feel of pain is a very different feature of the brain from the pattern of neuron firings that cause the pain. So you can get a causal reduction of pain to neuron firings, but not an ontological reduction. That is, you can give a complete causal account of why we feel pain but that does not show that pains do not really exist. (p. 31)
The Edelman chapter next was particularly interesting to me since it provided a sort of “Edelman in a Nutshell” type of explanation for his ideas. Edelman’s Neural Darwinism is another one of those books on my shelf that I have hardly read. One of the core ideas of Edelman is Neural Group Selection. The brain selects assemblies of hundreds to millions of neurons and pares back or lets die other groups. Up to 70% of neurons are lost during development in some parts of the brain in a process that strengthens some groups and eliminates others. Key to consciousness is notion of his neural maps. These are actually sheets of neurons with physical mappings that first relate the neurons to sensory input. However, Edelman views the brain as layers upon layers of maps that relate processing at one level to processing at other levels. Consciousness arises through reentry where signals go back and forth between the different levels of maps in parallel. For all of this to work, the brain requires memory, ability to learn, ability to differentiate self from non-self, and systems of categorization. Searle finds the neurological theory impressive but finally finds that Edelman has the same problem as Crick. There still is no accounting for how these interacting maps generate subjective experience.
Searle praises Penrose’s Shadows of the Mind for its explanations of quantum mechanics and writes it is among clearest non-technical accounts of it he has seen. While he spends some time on the idea of quantum computing occurring in the brain through cytoskeletons in neurons, Searle’s mainly focuses on the Penrose’s idea that consciousness is incomputable because of Gödel’s incompleteness theorem. The problem Searle finds with the argument is it “fails to distinguish between normative algorithms that are supposed to provide ‘unassailable mathematical reasoning’ and the sorts of algorithms that just simulate natural processes such as rainstorms and cellular mechanisms.” Searle accepts Weak AI: human cognitive processes can be simulated with a digital computer. He rejects Strong AI: information processes by themselves do not have and are not able to generate consciousness. Penrose’s argument tries to disprove both Weak and Strong AI.
The question “is consciousness computable?” only makes sense relative to some specific feature or function of consciousness and at some specific level of the description. And even if you have some specific function that is noncomputable, my seeing the truth of Gödel sentences for example, it does not fellow that the underlying processes that produce the ability are not themselves simulatable computationally at some level of description. (p 86)
In his “Consciousness Denied” chapter, Searle takes on Dennett’s Consciousness Explained by comparing it to a “performance of Hamlet without the Prince of Denmark.” Searle’s point is that Dennett denies the existence of exactly what he promises to explain in the title of his book. Searle praises Dennett’s explanations of neurons and neural connectivity but declares the book “makes no contribution to the problem of consciousness, but rather denies there is any such problem in the first place.”
You can’t disprove the existence of conscious experiences by proving they are only an appearance disguising the underlying reality, because where consciousness is concerned the existence of the appearance is the reality [bold is italic in original text]. (p. 112 }
Science might discover consciousness is an illusion like a sunset is an illusion but there is a difference between sunsets and Dennett’s consciousness. “Sunsets science does not deny the existence of the datum, that the sun appears to move through the sky.” Dennett’s version of consciousness denies the existence of the datum itself.
The simplest take on Searle’s view of Chalmers (The Conscious Mind) is that Chalmers is conflicted and can’t really make up his mind what he wants:
He accepts the entire materialist, functionalist story- strong AI and all – as an account of the mind up to the point where he reaches consciousness; but then to his general commitment to functionalism he wants to tack on consciousness which he says is not subject to functionalist analysis. In his view, the material world, with a functional analysis of mental concepts, has an irreducible nonfunctionalist consciousness mysteriously tacked on to it… Chalmers wants both functionalism and dualism. (p. 143-144)
Searle isn’t a fan of functionalism or dualism. About functionalism he writes:
The theory is, in my view, utterly implausible, but to understand its appeal you have to see it in its historical context. Dualism seems unscientific and therefore unacceptable; behaviorism and physicalism in their traditional versions have failed. To its adherents. functionalism seems to combine the best features of each. If you are a materialist, functionalism may seem the only available alternative, and this explains why it is the most widely held theory in the philosophy of mind today. (p 141)
Searle traces much of the “mystery” of consciousness to Descartes and Galileo from the seventeenth century. Their dualism broke the world into matter and a soul which was outside the scope of scientific research. I didn’t found the term “hard problem” mentioned in the index, although it was discussed implicitly in the Chalmers’s chapter. Some may get the wrong idea that Searle might think the “hard problem” can be solved by science. I think he would mostly likely think the “hard problem” is manufactured problem arising from Cartesian dualism.
Searle wraps up his reviews with Israel Rosenfield’s The Strange, Familiar, and Forgotten. I must admit some shock reading this chapter and discovering Rosenfield had already written several ideas that I thought were my own. I don’t recall ever reading this chapter. I don’t have any Rosenfield books as I would most likely have if I had liked his ideas. Either I developed my own ideas independently and after Rosenfield or, more distressing, is the thought that I actually I did read this chapter and incorporated its ideas as my own.
It’s a matter of memory. For Rosenfield, “not only is it impossible to have memory without consciousness, but equally it is impossible to have anything like a fully developed consciousness without memory. Consciousness arises from the dynamic interactions of the past, the present, and the body image…. our sense of self is precisely a sense of experiences affecting the body image, and all experiences involve this sense of self, and hence involve this body image.” From the persistence of this body image over time, through accumulation of memories, arises the self.
The discovery of the body image is not new in neuroscience, but it is one of the most exciting discoveries in the history of the field. In a sense all of our bodily sensations are phantom body experiences, because the match between where the sensation seems to be and the actual physical body is entirely created in the brain (p. 182)
We ought to think of the experience of our own body as the central reference point of all forms of consciousness… any theory of consciousness has to account for the fact that all consciousness begins with consciousness of the body. (p 184)
My conscious experiences of my own body as an object in space and time, an experience that is in fact constructed in my brain, is the basic element that runs through all of our conscious experiences (p. 185)
Searle believes consciousness is real and something science, primarily biology, must explain. He doesn’t rule out consciousness might exist in nonbiological entities, but he is clear that computation by itself, since it is nothing more than symbol manipulation, can’t provide an account of it. Whether the “hard problem” can be solved probably isn’t relevant. Science explains by finding regularities and correlations, then developing a plausible explanations for how the regularities and correlations relate to other known science. It isn’t so much explaining why “blue” looks blue. That may be never answered. It is about explaining how known or discoverable fields, forces, or information can produce consciousness.
Broad Speculations 