Tuesday, October 25, 2011
I have problems with the idea that consciousness is an emergent property of brain function. I simply cannot get my mind around it. I have tried to think about why, and here is some of my thoughts. First a quote from Koch, a neuroscientist that propagates this notion of emergence: "Consciousness emerges from neuronal features of the brain. A system has emergent properties if these are not possessed by its parts. There are no mystical or new-age overtones to this." (Koch; Quest for Consciousness ) But oh yes! There is!
This sweeping statement overlooks the difference between what is called weak emergence and strong emergence. David Chalmers explains the diffrence below; the first part describing strong emergence (as "inexplicable" and "magical"), and the second describes weak emergence (as selfevident).
"(1) Emergence as "inexplicable" and "magical". This would cover high-level properties of a system that are simply not deducible from its low-level properties, no matter how sophisticated the deduction. This view leads easily into mysticism, and there is not the slightest evidence for it (except, perhaps, in the difficult case of consciousness, but let's leave that aside for now). All material properties seem to follow from low-level physical properties. Very few sophisticated people since the 19th century have actually believed in this kind of "emergence", and it's rarely what is referred to by those who invoke the term favourably. But if you mention "emergence", someone inevitably interprets you as meaning this, causing no end of confusion.
(2) Emergence as the existence of properties of a system that are not possessed by any of its parts. This, of course, is so ubiquitous a phenomenon that it's not deeply interesting. Under this definition, file cabinets and decks of cards (not to mention XOR gates) have plenty of emergent properties - so this is surely not what we mean."
Strong emergence would simply mean that out of a certain functioning assembly of parts you get an effect that cannot be understood by seeing how the parts function together. An example of the difference between this two concepts of strong and weak would be the following: Imgine a mechanical clock. It's hands are moving and this movements are emergent properties ( in the weak sense) of the different parts (cogs, springs) of the clockwork. If the clock made a large sound every hour and this sound could not be explained by any of the functional parts of the clock, but would still disappear when you take the clock apart, that would be a case of strong emergence (the magic that Chalmers refer to). Nowhere in nature do you find examples of such "emergence".
The very notion of "complexity" leading to new "emergent" properties also to me seems rather dubious. There is something psychological about these concepts. Nature is not complex. We assign complexity to it. No truly new properties emerge from this imagined complexity. Every emergent phenomenon found in nature is conceptual, not physical. All physical objects consists of elementary particles and fundamental forces, located in spacetime. No object, no matter how "complex" it may be, has properties that transcend those of these basic constituents.Which to me seem to imply that consciousness is a "brute fact". A basic fact of the world.