AI doesn’t actually know what a hand is. In two-dimensional images, hands can appear in dozens of different positions: waving, flexing, holding an object, clenching a fist, or poking out of a pants pocket, partially hidden from view. Humans know that these visual discrepancies illustrate how a hand works. AI, without access to the three-dimensional world, knows only how a hand appears. Identifying a fist, thumbs-up, or peace sign as a hand is an impressive feat for AI, and we can hardly blame it for assuming a real hand could be a combination of the three.