I am cross posting this here from another philosophy forum.
A typical philosophical question is whether the Universe is deterministic or random. Modern physics tells that the second option is more likely. However, even if the universe is random, it could contain mechanisms that are deterministic for all practical purposes; mechanisms on whose operations randomness has only a negligible effect. So, is the brain one of such mechanisms?
If the workings of the brain are deterministic, then the behaviour of the brain is completely determined by:
1) received sensory data (a posteriori)
2) the "built-in software" and hardware (a priori)
(Assume physicalism for the sake of this discussion.)
On the other hand, if brains are not deterministic, there must be some random inputs to brain "algorithms". What could be the possible sources of such indeterminism? I can think of:
1) Quantum effects.
2) External random impacts, for example cosmic rays and radiation. They theoretically can create random errors in the operation of the brain.
3) Something like "uninitialized memory". I don't know if something similar to this concept exists in neuroscience, but I think that there should be some regions is brain that are like filled with random data - like computer memory contains random data after the computer has just been is turned on. Of course, the contents of the memory are in some way determined by the physical universe (at least probabilistically), but the determination is so complex, untraceable, and unrelated to the workings of the computer (or brain) that these data can be treated as random from the computer's point of view.
So I am interested what the modern science has to say about all that. I have heard that it's considered unlikely that quantum effects play significant role in the brain. Brain is a warm and chaotic environment, so quantum decoherence is expected to happen almost immediately. But can cosmic rays have an effect of our consciousness? And are the "algorithms" of the brain deterministic, or do they contain some truly random elements, like "reading from an uninitialized memory"? Are scientists working on these questions? To what extent they are answered at the present moment?
The bottom line: I am interested whether the brain can be simulated using a computer with a pseudo-random number generator or a truly random elements are required.