The one objection I can think of would be along the lines: what initiated the cascade of events that led to the muscles being activated? Simply, you could answer that the neurons firing in your brain started the march of action potentials that eventually led to the contraction—but what was the source of this neural activity in your head? In essence, what willed your brain to produce a seemingly novel action, or seemingly novel pattern of neural activation? Is it an incredibly sophisticated reflex, engineering by millions of years of evolution, and thus purely physical, or is there room for a separate causal agent to intervene? It seems to me that we can account for the causation of the content of the action in physical terms, but the causation of the origin of the action is slightly more subtle. I’m curious as to other thoughts on this.