[nooneelse]

Just to bolster your point that neurons can be influenced by radioactive decay (in case a reader were wanting to dispute any direct influence exists): a person with a Geiger counter can make a decision of any kind based on the parity of a count produced by it. "Even I turn left and go to work, odd I turn right and go to a park."

[manmal]

Great point! Given the current state of affairs in quantum physics (again, AFAIK), it can then be argued that there is no real determinism, but randomness and "chaos". (entropy increases in the universe, etc)

I can live with that :)