Your thesis would seem to indicate that, proportionally, most philosophy is about people’s hands, followed by philosophy about people’s chins and lips? or did I miss something?
First, this doesn’t make any sense. Philosophy (and its expression) are proportional to what part of the homunculus?
Second, the homunculus in the brain represents the amount of cortex devoted to tactile sensations coming from different parts of the body. What has this to do with philosophy?
I think he means that the tongue (speaking) and the hands (toolmaking, writing, etc) are the tools of philosophy. That’s kind of obvious but it’s probably true.