“Perhaps someone will see an opportunity to be clever, and say: “Okay. I believe in free will because I have free will. There, I’m done.” Of course it’s not that easy. My perception of socks on my feet is an event in the visual cortex. The workings of the visual cortex can be investigated by cognitive science, should they be confusing. My retina receiving light is not a mystical sensing procedure, a magical sock detector that lights in the presence of socks for no explicable reason; there are mechanisms that can be understood in terms of biology. The photons entering the retina can be understood in terms of optics. The shoe’s surface reflectance can be understood in terms of electromagnetism and chemistry. My feet getting cold can be understood in terms of thermodynamics. So it’s not as easy as saying, “I believe I have free will because I have it—there, I’m done!” You have to be able to break the causal chain into smaller steps, and explain the steps in terms of elements not themselves confusing.” (Eliezer Yudkowsky, Rationality)