Your hand being cut off is maybe just a convenient abstraction, imparted on us socially or genetically. We agree that it was because we roughly agree on what th

Your hand being cut off is maybe just a convenient abstraction, imparted on us socially or genetically. We agree that it was because we roughly agree on what the essence of a hand is and what it means for it to be cut off, but that's not all there is to what happened. Similarly, that I can scrawl a few crude lines in a particular shape and have everyone agree that it looks like a face doesn't mean that it's an accurate representation or that everyone perceives the same thing. It may embody the shared essence of a face, but people will still disagree on what exactly it represents. Is it smiling or smirking? Tired or just squinting? Old or young? The devil is in the details. Perception is as far as I know only partially based on sensory stimuli. Also important are the abstract concepts we use to make sense of the world and memories of past impressions. We might easily agree that your hand was cut off because we agree on a pretty fundamental level what these things mean, but that's not a very fine-grained description of what happened. Ask people how long it took and you'd probably find some interesting differences in perception.