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Nitpick - your eyes are, in combination, a 3d sensor. Individually they're 2d sensors, but together they can detect three dimensional information.

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Strictly speaking this doesn't make them a true 3d sensor, but rather a 2d sensor with an accompanying depth-map. In order for them to be true 3d sensors they'd be have to transmit information about both the near and far sides of an object simultaneously, for example.

Very true, a 4 dimensional being with 3 dimensional eyes would be able to look inside closed boxes, and see every side of every object at once. (just like we can see every part of a 2d scene all at once)

Not merely 2d + depth perspective.

Arguably, humans are 4-dimensional beings living in a 4-dimensional world—it’s just that one of the dimensions is accessible with much fewer degrees of freedom.

(Not unlike how a seemingly 2-dimensional world of a top-down FPS is actually 3-dimensional, you just have to follow way more rules when it comes to moving in the third one.)

Hmmm... Agreed that they're mostly 2D sensors, but apart from near-field the post-processing brain can use depth-cues to for us 'see' in 3D. Also, you don't see in 3D unless your head/eyes/target is moving, right?

You definitely get 3D from just having twin perspectives on an object. You get even more when moving your head.

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