18 May 2013 16:56:00
Anyone familiar with Dennett's previous books, such as Darwin's Dangerous Idea, Consciousness Explained or The Intentional Stance, will have a pretty good idea what to expect from this latest – though they may well decide that they need not have bothered, as so much has been drawn from the earlier ones. Dennett's recycling credentials would do credit to the deepest of Greens.
As he explains, the origins of the present volume lie in a course he ran for 13 freshmen philosophy students. In Socratic style, he leads the intrepid and presumably naive group expertly through the minefields of philosophical errors and rhetorical ploys – the first half of the book – until they, and we his readers, are judged ready to join him, via a long detour into computer programming, in an assault on his traditional opponents. No prizes for guessing that these are critics of his ultra-Darwinian take on evolutionary mechanisms, and those who are troubled by the "problem" of reconciling conscious experience and free will with a materialist ontology. As previously, his particular target for the former is the late and much lamented palaeontologist Stephen Jay Gould, and for the latter the still impressively active philosopher John Searle.
His approach to educating his students about philosophical pitfalls and techniques of argument such as oversimplification and reductio ad absurdum (Dennett calls them intuition pumps) is a master class in philosophical theatre, packed with snappy vignettes – thought experiments in the absurd to skewer his opponents. Neologisms abound. An entire chapter is devoted to "three species of Goulding" – deconstructing Gould's writing style as "rathering, piling it on, and the Gould two-step". That is, employing emphatic verbiage to hide a lacuna in the argument. Some might say it takes one to know one.
Thus one of Dennett's recurring vignettes involves "Swamp-man". Lightning strikes a tree in a swamp and incinerates a person standing beside it. Simultaneously the tree is transformed into an exact molecular replica of the deceased. Would the replica be that person? Even though no one could tell the difference, it would not be, Dennett asserts, because "in the real world past history and future function are bound together by … evolution, development and learning". He's spot on about the real world, but he then goes on to claim that there is "no real substitute for these natural accumulation processes". Note how the pace, self-assurance and italicised emphasis of Dennett's prose protect against the legitimate objection that a genuine molecule-for-molecule replacement of him by Swamp-man would indeed carry precisely these traces of his past embodied in his physiology and immune system and the dynamic connections between the billions of nerve cells in his brain.
All this is a precursor to "tools for thinking about evolution". Darwin's theory of evolution by natural selection is, of course, a syllogistically minded philosopher's delight: (1) like begets like, with variations; (2) all organisms produce more offspring than can survive to adulthood; (3) those variations better adapted (fit) to their environment are the more likely to survive and reproduce in their turn; (4) thus such favourable variations, if inherited, are likely to be preserved in subsequent generations. For Dennett, this is the best idea anyone ever had. Following Richard Dawkins, he sees the unit of selection, that which persists across generations, as the gene, a prime mover embedded like a computer program driving the "lumbering robot" that is the living organism.
But genetic and evolutionary thinking have moved on. Since the sequencing of the human genome in 2000 and the rise of epigenetics, the very concept of "a gene" as a discrete strand of DNA has been discarded. Even such previous allies as EO Wilson have embraced the possibility of higher levels of selection, of groups and species, leaving Dawkins somewhat isolated in his reductionism. Today we see evolution working at many levels, from molecular to ecosystem, and with many forces at play. Dennett can only nod towards these current understandings. Above all, he sees the Darwinian syllogism of evolution by natural selection as a "universal acid" that applies to animate and inanimate alike, to species and societies, to technologies and philosophies. He even endorses Dawkins's notorious memes – those fashions in clothes or "units" of thought or snatches of song that are said to inhabit our minds – a fantasy so witheringly demolished by the formidable Mary Midgley.
It is however when he comes to consciousness and free will in the last quarter of the book that Dennett is simultaneously at his best and his most confused. His strength lies in exposing the vacuity of such old philosophical chestnuts as "qualia" – subjective first-person experiences (the blueness of the sky) seemingly unapproachable by objective external observers. Or zombies – creatures who look, sound and behave just like people but are not conscious. The core of Dennett's argument lies in his refutation of John Searle's famous Chinese Room thought experiment, which had been intended to demonstrate the irreducibility of consciousness. Searle, who knows no Chinese, imagines himself inside a room, into which someone feeds messages written in Chinese. He has a set of Chinese symbols and instructions in English telling him which ones to use in reply. Thus to the outside observer Searle seems to be responding consciously, yet manifestly he is not. Dennett points out that the fallacy lies in locating consciousness in Searle, who is merely a low-level robot in a complex system, whereas it actually is an emergent property of the entire system in which Searle is embedded. So for Dennett, computers consisting of layer on layer of mindless programs can indeed achieve consciousness, at least in the very restricted sense in which philosophers – and neuroscientists – use that multidimensional word.
So where's the snag? Go back to that sentence about the real world in which experience is bound together by history, evolution, development, learning. Throughout the book, Dennett insists that meaning is more than mere information. As he repeats several times, it isn't your brain that is conscious, it is you. You need your brain to have a mind, to be conscious, just as you need legs to walk. But meaning, minding and consciousness are higher-order processes, requiring but not reducible to the billions of mindless neurons firing away inside your brain. They also require your active engagement with the natural, human and technological world around you.
Alas, at the crucial moment he fails to have this insight. Fatally he can't tie together his commitment to evolution with his concern for consciousness. So he doesn't address the question of how and why consciousness emerged during primate evolution. If he did, he would surely see that such a property is a functional requirement for highly social creatures such as us humans. We need to be able to recall our own autobiographical past and locate our selves with reference to other thinking selves, to have a theory of mind. Blind-sighted by his reductionism, he cannot see that consciousness demands not only an embodied brain but an embedded body, emerging through the interchanges of individual humans with each other and the worlds we inhabit and create.
If you've never read Dennett, Intuition Pumps is the one to go for – a distillation of all that he has written before. You'll enjoy and be challenged by it. But read it sceptically. Learn from his demystifying of the tricks and rhetoric of philosophical argument – and don't be afraid to turn them against the author himself.
