Know what'll really bake your noodle? An MRI will show your brain firing to move your arm before your "higher" brain function sends the signal.
Your brain fires and then sends an executive summary to the homunculus behind your eyeballs saying, "Good job! 'You' moved your arm!" And you believe in free will?
Don't some limbs move due to neurons in the spine or other parts of the body? Such as when you get burned or struck by something. To make the reaction quicker, it just bypasses the brain
Spinal cord reflexes are simple behaviors produced by central nervous system (CNS) pathways that lie entirely within the spinal cord. The sensory afferent fibers that evoke these reflexes enter the spinal cord and activate spinal motor neurons directly or through a chain of one or more spinal interneurons.
“You” really are just an observer of biological programming playing out. Even your “higher” brain functions are still being observed by someone. They are a response to the more “base” biology, but they are still programmed responses.
"You" is an incredibly tricky word to define. Is your body you? Is your brain you? Is the set of chemical reactions we call consciousness you? Is only the subset of that set of chemical reactions that's capable of saying "I am me" you?
I stuck my arm out towards a cat today and it scratched me. What me did it scratch? If my arm gets amputated because that scratch gets infected, have I lost a part of myself, or have I simply lost some thing that belongs to me?
It's not even one brain, it's two chunks that function as one whole. Patients who have had a corpus callostomy (splitting the membrane connecting the hemispheres) can find one of their limbs going against what you're trying to do.
If you're getting dressed, for example, your left side may refuse if it doesn't like what you're wearing. It can do totally random things and sometimes people have to use their controlled hand to physically restrain the other.
They think the left half of the brain is responsible for speech and communication, so the right remains this silent observer under the thumb of the left when the connection is intact.
But it has its own will, even if you don't know it.
When I think about how I move my limbs my brain starts melting.
You think about moving your arm, but you don't actually think about it, you just do it, so how do you move it without thinking that's what you're doing?