Asklemmy

Now see, if you're looking at things from a biological point of view, it's important to recognize the forest from the trees. A few trees are, well, just a few trees. But a great many trees together constitutes a forest, and becomes more than the sum of its parts. I feel the same way about the human brain. Yes, it's a series of electrical and chemical impulses, but there are so many of these working in tandem that it becomes exponentially more complex, akin to ever-advancing computer technology. It's complex enough that we think, we talk, we make decisions. And those decisions aren't based solely on instinctional drive, and can even be made in opposition to them.

It's true that human behavior can be accurately predicted based on an individual's natural tendencies, but there are never any guarantees. There's always a choice, a chance to veer off course. Decisions can be prudently made after careful research, or made on a frivolous impulse. Maybe you even realize that you would ordinarily take one action in a given situation, but do the exact opposite. You consciously chose to ignore your first impulse. If free will is an illusion, it's a damned convincing one.