For thousands of years, pinpointing the exact purpose of the human brain, and defining its physical characteristics, has remained a challenge to philosophers in western civilisation.
Back in ancient Greece, for instance, Aristotle speculated that the brain may just be an organ for cooling blood. If the parts were connected by nerve fibres, the Greek polymath suggested, perhaps they communicated with each other somehow? René Descartes, a prominent figure in the European Enlightenment, later claimed that some nerve fibres in the brain were like bell-pull wires. Following that rather vague speculation, however, the philosopher couldn’t offer anything beyond guessing. And then in the 20th century, the narrative of how the human mind works changed, becoming predominately preoccupied with arithmetic and materialism. This happened in the mid-1930s, when a mild-mannered English mathematician, Alan Turing, suggested that the brain could be composed of individual parts which may simply be mechanical, and contain no mystery or magic. Turing then came up with another novel idea. If these parts were organised to interact together in clever ways, they might be able to compute information.
Thus, the idea of a “computer” was born.
Maybe then, Turing surmised, the brain itself is like a computer: processing information by slavishly following huge lists of simple instructions. Turing formally declared concepts such as an algorithm and computation, both of which he explained within the Turing machine: a triple correspondence between logical instructions, the actions of the mind, and a machine which could in principle be embodied in a practical physical form. Turing is now seen as the leading pioneer and founding father of intellectual disciplines such as computer science and artificial intelligence.
For over half a century now, the American philosopher, Daniel Dennett, has been attempting to understand the evolution of the human mind from this materialistic and mathematical perspective. Turing has been something of an intellectual hero in Dennett’s career thus far. Especially when it comes to figuring out three major questions in Dennett’s work: how did the mind evolve in the first place? When and why did language evolve within the mind? And what exactly is human consciousness?
There are currently no clear-cut answers to any of these questions. However, Dennett feels he is approaching a point in his career where he is, at the very least, on the cusp of answering them with some sense of reason and clarity.
“One of the great things about the basic idea of a computer is that we know, to a moral certainty, there are not any miracles inside it,” Dennett explains from a hotel lobby in central London. “It’s just basic operations and simple blind mechanical actions.”
“Turing’s computer model promised to take away the mystery of the mind, and now it’s doing it,” Dennett adds.
Language and the brain
Dennett is well known in the field of philosophy for making bold and brash claims. And while his high-minded intellectual reputation certainly precedes him, it has also made him a few enemies along the way. In his new book, From Bacteria to Bach and Back, Dennett takes a few hard-hitting pops at one of those enemies, the linguist and left-wing political activist, Noam Chomsky. Chomsky pioneered the idea of the ‘Language Acquisition Device’ (LAD), which posits that all humans from birth possess an innate understanding of the fundamental rules of language. The LAD is a theoretical attempt to solve the question of why children so readily and instinctively learn new complex language systems, and why languages seem to share many of the same basic characteristics such as syntax and grammar. Chomsky later developed his ideas into the theory of ‘universal grammar’, which states that the human brain in fact has an innate biological understanding of grammatical categories, such as nouns and verbs, that facilitate language development and processing. This suggests that there are some things that can’t be explained by way of evolutionary psychology alone.
This view of the brain does not look favourably on evolutionary accounts as to how language originated. So, what exactly about this subject do Dennett and Chomsky fundamentally disagree upon?
“Chomsky has been a leading theorist of language for decades,” Dennett explains. “But one idea which he refuses to abandon is that language didn’t develop by gradual evolution. Chomsky wants to have a giant leap [to understand the origins of language, ed.] that does not have an evolutionary explanation. Perhaps an explanation in physics, I guess. I find that incredible.”
In Dennett’s latest book he also declares— with just a slight touch of hubris— that fifty years of thinking and writing about the human mind has enabled him to discover a path which shows that there is absolutely nothing miraculous about it.
Vitalism—a doctrine that claims the functions of a living organism are due to a vital principle distinct from physicochemical forces— is essentially dead in physics, Dennett is keen to point out. This, in his opinion, is proof that everything about the process and mechanics of the mind can be worked out in detail. If, of course, scientists and philosophers are willing to put in the groundwork and disbelieve the idea of Élan vital, which states that there is some unknown, creative force that enables growth in organisms.
“We pretty much understand what life is now,” Dennett confirms with a sense of self assurance which can border on arrogance, depending on how sacred you perceive the human mind to be.
“So, there are no longer any great horrible mysteries facing us,” he says.
“There is plenty of hidden detail still to be worked out. But we have put vitalism to bed. And I think we are approaching a time when we can put dualism to bed too,” Dennett adds.
Dualism is an idea first outlined by René Descartes, in books like Discourse on Method (1637) and Meditations (1641) where the philosopher stated that the nature of the mind is completely different from that of the body. Thus, in Descartes’ view, it is possible for one to exist without the other. Dualism gave rise to the famous problem of mind-body causal interaction, which is still a hot topic of debate for some philosophers today.
Dennett believes that Descartes’ ideas have strongly influenced and steered the topic of the mind— and consciousness especially— in the wrong direction ever since.
“The fundamental problem with dualism is that it seems to violate energy conservation laws,” Dennett explains. “If dualism is true, it looks as though the mind cannot have any effects on the world. But if the mind cannot have any effect on the world, then what makes us think it exists? You cannot have it both ways,” says Dennett.
“A gold rush in neuroscience”
As a philosopher who puts a firm faith in Darwin’s theory of evolution by natural selection as a tool to work out how the mind evolved, Dennett says he takes a harsh view of traditional philosophy of the mind. Such views don’t deem the discoveries and basic premises of science to be important. Dennett, on the other hand, takes what he calls a “a scientific approach to philosophy”. Essentially, this involves using data from the natural sciences in his philosophical thought experiments. And crucially, it involves spending some time in the laboratory, and not just burying one’s head in ancient textbooks in the library. In books like Consciousness Explained (1991) and Intuition Pumps and Other Tools for Thinking (2013), Dennett has made the argument that consciousness — that is all the thoughts and experiences that we can reflect on and think about — can be explained fully without having to refer to some mystical force. Dennett also argues that there is no single place in the brain where consciousness comes together. Instead, he believes that the brain consists of a bundle of semi-independent agencies. If natural selection can create life itself through an algorithmic process, Dennett has continually asked in his work, why then shouldn’t the brain be able to create consciousness too?
Like the evolutionary biologist, Richard Dawkins, who Dennett quotes throughout many of his books, the philosopher believes that Charles Darwin’s idea of evolution by natural selection, first explained in The Origin of Species (1859), is the single greatest idea any scientist has ever come up with to further our understanding of the origin of life.
Evolution by natural selection is not itself a designed thing, or an agent with purpose: it’s just dumb luck, Dennett explains.
“Natural selection doesn’t happen due to any particular talent or virtue that some organisms have, and the others don’t have. It’s just that they all have variations. And variations develop in different ways in different organisms, depending on the individual circumstances they find.”
Over the long run, what will most likely emerge from that process of natural selection is a gradual honing in on and a refinement of design features, Dennett posits.
“There is no observer in natural selection, and there is no smart selector at work,” he says. “It’s just reproduction. And reproduction occurs unsupervised. And when you see what reproduces, and what doesn’t, you see that it’s the ones who do better that survive,” he says. “The organisms don’t have to understand those reasons. Nobody has to. Natural selection is not guided by a rational intelligent agent. But it’s a very powerful generator of good design.”
Dennett, numerous other scientists, and a host of evolutionary psychologists (most famously Steven Pinker) all believe that any relevant questions needed to further our understanding of consciousness can be answered by strictly studying brain activities. Crucially, though, without any recourse to subjective experience.
I remind Dennett that there are many in the publishing world, and indeed in academic circles, who disagree with his sure-footed ideas on this subject. Yuval Noah Harari, author of Sapiens and Homo Deus, being one of them. Harari recently told Scenario in an exclusive interview that Dennett’s view on consciousness “isn’t quite there yet” (SCENARIO 01/2017). Harari went on to say that while we are presently able to find correlations of consciousness, we are not even close to having a satisfactory answer to why millions of neurons firing in a pattern go on to create subjective experience like love or anger.
“Well there is a sense in which Harari is right,” Dennett concedes, when I put this point to him. “But it’s not very telling. Indeed, we don’t have good models of the actual functionality of those portions of the nervous system. But we have plenty of evidence and empirical tools which help us to explore, and to make predictions and see how they turn out. So, we are making progress. A lot more than people think.”
Dennett says that we are presently in a period that is “like a gold rush in neuroscience and the study of the mind.”
“Many pieces are falling into place,” he says. “Sure, there is a tremendous amount more to do,” he admits. “And there are big gaps in our understanding. But it’s picking up speed. For a long time, it was considered too risky and speculative for a neuroscientist to talk about consciousness. That is changing now. Even in the most rigorous and high powered labs, people are beginning to talk about models of consciousness. They wouldn’t be doing that if they weren’t making progress.”
The mind system
Dennett’s latest book can in many ways be seen like a ‘best of’ collection, amalgamating his half century of thinking about the mind, and using bits from his other books to gather several ideas in a single, reader-friendly tome which eschews academic jargon and looks to a mass popular audience. One key idea that has been central to his understanding of the mind— even of life itself— is reverse engineering. This idea works from the basic premise that every living thing is a product of non-mysterious physical forces that gradually bring all the elements together, refining them along the way, and eventually arrived at a working system that we can now observe.
“Biologists, when they look at any system, want to know how it works,” Dennett explains, fleshing out the idea in more detail. “So, they say, here is a natural device, it’s designed by evolution to do some job. It’s possible that some of the parts may be there for historical reasons, they could be removed or left over from some earlier period. There are traces of the history of the process. But you can be sure that anything that is energetically expensive, is doing something that is important.”
The trick is to see how it works, says Dennett: “That is reverse engineering. Really, it’s the same enterprise that engineers use. If they pull up a submarine off the ocean’s bottom, they are going to go over it with a fine-tooth comb and see what machinery is in there. This can then tell us if there is anything to be learned about how to design and build such a thing.”
Much of Dennett’s work spends considerable time and effort looking backwards to see how self-designed natural entities fit together, work and survive evolution. But the philosopher also has a habit of looking forward, anticipating what the future may bring for the human species. After all, in just a few short decades, Dennett points out, we have come a long way from the basic model of the Turing Machine that outlined what the human mind was capable of if it worked in tandem with bottom-up design and simple mathematics.
Dennett has spent the best part of an hour chatting about many interesting concepts and ideas that relate to the life of the mind. But concluding our conversation today, I feel a fitting question to put to him is one that he raises himself in his latest book: could something as intellectually sophisticated as a digital computer ever evolve from bottom up natural selection?
“I’m sure it’s possible in principle,” he says. “I’m hesitant because there are lots of things that are possible in principle, but that would be too stupid and expensive to actually carry out in practice. Ray Kurzweil and others, for example, think [machines becoming conscious, ed.] is inevitable. But I don’t think there is a reason why that should be the case. We have every reason to believe that it is possible, in the foreseeable future. But it doesn’t have to be. And it’s not desirable, either.”