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A Ridiculously Brief Overview of Consciousness
A five-minute guide to the debate by Rick Lewis.
Modern philosophy of mind began with René Descartes (1596-1650) who argued that we each consist of two different entities: a material body subject to all the laws of physics and an immaterial mind, which isn’t. This theory is therefore known as Cartesian Dualism. He said that the mind was connected with the brain via the pineal gland. But exactly how, to take a very simple example, does my wish to scratch my nose result in my arm being raised and my finger making scratching motions? How can something non-physical – the mind – have a causal effect on something physical? Over the next few centuries, various modified versions of Dualism tried to address this problem. According to epiphenomenalism, for instance, the interaction was only one way: the brain affected the mind, but the mind had no effect on the brain. The mind was therefore a passenger carried along in a purely physical machine, with only the illusion of an ability to influence events. Alternatively, according to occasionalism, the interaction was two-way, with God intervening directly on each occasion that it was necessary for the mind to influence the brain or vice versa.
All of this dualistic speculation came to a shuddering halt in 1949 with the publication of GilbertRyle’s classic Concept of Mind. Ryle abusively called Descartes’ theory the ‘dogma of the ghost in the machine’, and argued persuasively that Descartes had made a ‘category mistake’ by treating the mind as another ‘thing’ in the same category of things as the brain, rather than as something from another category altogether (a process, perhaps?)
Physicalism is the view that there is nothing in the world over and above the entities dealt with by physics. The next major theory of mind was physicalist: it was the Mind-BrainIdentity Theory propounded by J.J.C. Smart (an occasional Philosophy Now contributor!) According to this, the mind is the same thing as the brain, and each state of your mind is equivalent to a corresponding state of your brain. This was followed by functionalism, another physicalist theory which argued that processes in the mind were identical to processes in the brain. (This opened up the theoretical possibility that conscious brains could be made out of something other than biological matter).
However, some philosophers began to argue that simply claiming that the mind and the brain were the same thing described in different ways left something important out of the picture, namely consciousness. There are a few famous arguments which crop up again and again in such discussions:
• What Is It Like To Be A Bat? In a famous paper of this name, Thomas Nagel argued that there is subjective experience which can’t be comprehended scientifically. We can find out how a bat’s body works but only a bat can know what it is actually like to be a bat.
• The Chinese Room: In John Searle’s influential thought experiment, a man sits in a room which has a slot in the wall. From time to time cards with symbols on them drop through the slot. The man doesn’t understand the symbols, but looks them up in a book of instructions and in accordance with what he reads, picks other cards, also with symbols on, which he pushes out through the slot. The symbols are in fact Chinese characters, and the man is effectively answering questions in Chinese, even though he doesn’t know it. Searle suggested this shows that even if we built a computer which sounded intelligent and answered all our questions convincingly, that wouldn’t mean that it knew what was going on.
• Zombies: Anti-physicalists claim that if the physicalist model was accurate, then we’d all be zombies. They mean that we’d be carrying out all our normal tasks and activities but that we’d all be devoid of any conscious experiences. Since (they say) we do have conscious experiences, physicalism must be wrong.
• The Hard Problem: David Chalmers said there are several different problems of consciousness, not just one. He draws a distinction between the easy problems (for instance understanding how integration and verbal report work) and the hard problem (understanding how we have subjective experience).