Free will probably exists in humans

>> Free will: "...a particular sort of capacity of rational agents to choose a course of action from among various alternatives." (Stanford Encyclopedia of Philosophy) Free will is a very tricky debate, and that's what makes it so much fun! We can see the trouble we get into just by looking at the definition about: we define free will as the ability to choose. What does it mean to choose, though? Even "rational agent" may be circular if we probe it far enough. Before we begin let me just lay out what free will is not. I do not believe that there is any sort of spirit or soul associated with our physical body. I believe that all decision making happens entirely through electrical and chemical interactions in the brain. I also do not believe that quantum physics allows room for free will. For starters, randomness is not free will, and we do not know enough about the brain to know how much effect quantum events would have. Not that the universe is wholly deterministic, but I believe free will is entirely compatible with a clockwork universe. Saying what free will IS, on the other hand, is much harder. We all know what it means intuitively, but any definition we try to give it breaks down. In this regard, we are like Potter Stewart, who could not define pornography but swore "I know it when I see it". I have my own personal definition: in a nutshell free will is defined by the ability of an agent to assign qualities to actions, act upon the one with the best quality, and choose (recursively) what qualities to rate the actions by. The infinite regress stops at biological desires, and the more steps between that an the actual choice, the more "free" it is. That definition captures my own intuitive notion of what free will is, but I suspect my opponent may have a different notion for which my definition does not apply. My stance is that "free will" is a label that we assign to the behavior of rational agents. It "exists" in the same sense that humor, intelligence or compassion "exists". They are not things you can hold in your hand, but labels we assign. Since I don't believe in the supernatural, I accept that our bodies are comprised of particles that obey the same natural laws as any other mass. How can we say that we can choose our actions, if our actions are just the result of particles interacting with each other? You could explain a person's behavior in terms of particles interacting. You could also explain a dance by charting the electric impulses sent to the muscles of each dancer, or a symphony by the vibrations produced by the sound waves. However, so much information is available at this level that our brains can not process it all. It would be noise to us! We understand the world by categorizing it and finding patterns within all that information. Our minds can not comprehend the vast amount of physical and chemical interactions that go into a simple decision. However, by using the "free will" model of human behavior, things make much more sense. In this model, people have their own desires, and they choose whether or not to act upon them. We understand all decisions in terms of the motivations behind them. Many human qualities, such as courage, compassion, and discipline, only make sense in terms of free will. I suspect my opponent will point out that being useful doesn't mean its "real", and in fact I have even admitted that free will is not "real" in the sense that its nothing more than a label. However, we still disagree in that I believe free will qualifies as something real, even if it is not an actual THING. I will turn the discussion over to him to see what his arguments against the existence of free will are.