“Determinism is one of the bedrocks of modern science. It is the principle that the future (or present) state of any system (say, a stick of dynamite) is determined solely by its past. If you know the precise configuration of any system, by adding the laws of physics and chemistry, you can calculate its future behavior.

There is nothing that the dynamite can do, no action it can take when it is likely to explode. It does not possess the ability to direct its own actions. However, if we similarly determined the pigeon's precise chemical composition and added the prevailing temperature, wind conditions. etc., could we predict that it would fly up into the air? Perhaps.

McFadden's quantum dualism model, which he uses to argue that pigeons are different from dynamite, e.g. in their ability to fly, the former being governed by indeterminism science the later by deterministic science, because "the pigeon (or man) is not an automaton; its conscious electromagnetic field exploits quantum measurement to move particles in its brain, proving it with the phenomena of free will, according to which consciousness drives free will." [1]

But then, suppose it spied a bag of seed on the ground. It would then be more likely to descend towards the food. But perhaps there is a cat nearby. The pigeon might decide to wait in the tree until the cat has crept away. Could we predict all these possible behaviors by analyzing the chemistry of the pigeon alone or even that of the pigeon and its surrounding environment? The only differences which have led to the pigeon's altered behaviour are the pattern of light photons that fell upon its retina (carrying the images of food, cat, etc.). If we include these photons in the equations of motion that describe the pigeon and its environment would the equations predict such widely different outcomes?

I hope to convince you that the answer to this question is no. We cannot account for life with classical science alone. In particular we cannot account how living creatures are able to direct their actions according to their own internal agenda. For higher animals, such as ourselves, we call this ability our will. The ability to will actions is a profoundly puzzling aspect to living organisms that appears to contradict scientific determinism. There is no role for will in determinism; we do not have choices.”