"But what IS gravity?"
Alexio loves to ask, "but what is gravity? All you've done is describe what gravity DOES." I am really curious as to why he thinks there HAS to be a THING. Why can't there just be functions. Operators. Structural realism. Sure, this doesn't jive as well with his preconceived notions about panpsychism and "indivisible units of consciousness," but I don't think he should dismiss it outright. And even if THINGS do exist, what makes you think that we could even begin to determine what they are, epistemologically.