Good point! We only think the left-right flip is isolated from the rotation (and therefore breaks symmetry) because our brains do (specifically) the rotation around a vertical axis so naturally that we don’t even notice it. Mirrors don’t seem to flip things vertically because our brains don’t intuitively do the rotation around the horizontal axis without us noticing.
In fact, this suggests an example. Imagine a person (I’m imagining my nephew) is lying on their side looking at the mirror, and you’re standing behind them standing upright. When you look at this person and their reflection, is their reflection (intuitively) flipped horizontally, or vertically?
Good point! We only think the left-right flip is isolated from the rotation (and therefore breaks symmetry) because our brains do (specifically) the rotation around a vertical axis so naturally that we don’t even notice it. Mirrors don’t seem to flip things vertically because our brains don’t intuitively do the rotation around the horizontal axis without us noticing.
In fact, this suggests an example. Imagine a person (I’m imagining my nephew) is lying on their side looking at the mirror, and you’re standing behind them standing upright. When you look at this person and their reflection, is their reflection (intuitively) flipped horizontally, or vertically?