Saturday, October 29, 2005

mind and matter

The mind is our thoughts and intentions and beliefs and such. The brain is that lump of gray tissue behind the eye sockets. Some people believe that the mind is nothing but brain activity. In other words, they believe that mental experiences arise from the action of the brain analogously to the way a magnetic field arises from a moving current. People who believe this are called physicalists.

Others, called dualists, believe that minds are inherently different from anything physical and cannot possibly arise from physical processes. I won't go into the arguments for dualism right now, but I want to address an argument against dualism that that they are discussing over at the Maverick Philosopher.

In that discussion, Malcolm Pollack asks
2. How is the mind connected to the brain? How is the causal linkage of a non-material entity to the macroscopic physical world achieved, without violating all sorts of conservation principles?
Bill Vallicella answers that this argument begs the question. Apparently he believes that there is no problem with a world in which the mind regularly violates conservation principles.

I on the other hand do have a bit of a problem with this. I'm not going to say that it is impossible that the laws of physics could be violated. Quite the contrary, I have no problem, for example, believing in the miracles of the Bible. The laws of physics are, as physicists finally realized in the 20th century, only relevant under the conditions in which they have been measured. Newtonian mechanics works fine under certain conditions, but when scales are large enough or small enough, then the rules need to be modified.

We have not measured physical properties at the point of interaction between the mind and the matter, so we don't really know what those laws are, but there are certain laws that are more universal than others. In particular, the laws of conservation of momentum and energy seem to be relatively sacrosanct. A universe in which these laws did not hold would be very strange. Still, there are several ways that the mind could interact with matter without violating either law.

1. classical physics
The first way is that all interactions can simply be constructed to preserve energy and momentum. The mind doesn't just send an electron off to spark a nerve impulse; it creates a repelling force between the electron and its nucleus so that the electron flies off yet the conservation of momentum is preserved by an equal and opposite reaction on the nucleus.

Of course this puts the atom in a higher energy state which would create energy if not balanced out. So the next atom over is altered to make it grab an electron. This sends that atom to a lower energy state to exactly balance the higher energy state of the first atom.

2.quantum randomness
Physicists tell us that certain physical events are truly random –not just that we can't predict them, but that the causes genuinely do not completely determine the effects. The normal example of this physical randomness is nuclear decay, but the process whereby an atom falls to a lower energy state and emits electromagnetic energy is also random in this way. The mind could control nerve impulses by effecting this random behavior. Since the physical causes do not fully determine what happens, there would be no (non-statistical) violations of physics if some non-physical cause were to determine what happens.

3.quantum superposition
Maybe the universe really does exist in a constant state of quantum superpositions and is only resolved to specific results by the observation of a mind. In this case, the mind could have a very limited power of controlling the collapse of the wave function, just within the scope of the brain. Or perhaps only at a few locations inside the brain.

So there are ways that the brain and the mind could interact without violating the fundamental conservation laws. They still must violate some physical laws. Even with the quantum mechanisms, the operation of the mind would cause result in statistical results that would be not as predicted by a pure physics. Still physics is only reliable within the parameters of which we have experience.

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