You are still sensing heat across 2 dimensions of skin.

The 3rd dimension gets inferred from that data.

(Unless you have a supernatural sensory aura!)

The point is that knowing where your hand is in space relative to the rest of your body is a distinct sense which is directly three-dimensional. This information is not inferred, it is measured with receptors in your joints and ligaments.

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Nevermark 6 days ago | parent [-]

No it is inferred.

You are inferring 3D positions based on many sensory signals combined.

From mechanoreceptors and proprioceptors located in our skin, joints, and muscles.

We don’t have 3-element position sensors, nor do we have 3-d sensor volumes, in terms of how information is transferred to the brain. Which is primarily in 1D (audio) or 2D (sensory surface) layouts.

From that we learn a sense of how our body is arranged very early in life.

EDIT: I was wrong about one thing. Muscle nerve endings are distributed throughout the muscle volume. So 3D positioning is not sensed, but we do have sensor locations distributed in rough and malleable 3D topologies.

Those don’t give us any direct 3D positioning. In fact, we are notoriously bad at knowing which individual muscles we are using. Much less what feeling correspond to what 3D coordinate within each specific muscle, generally. But we do learn to identify anatomical locations and then infer positioning from all that information.

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reactordev 6 days ago | parent [-]

Your analysis is incorrect again. Having sensors spread out across a volume is, by definition, measuring 3D space. It’s a volume. Not a surface. Humans are actually really good at knowing which muscles we are using. It’s called body sculpting. Lifting. Body building. And all of that. So nice try.

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Nevermark 5 days ago | parent [-]

Ah good point. 3D in terms of anatomy, yes.

Then the mapping of those sensors to the bodies anatomical state in 3D space is learned.

A surprising number of kinds of dimension involved in categorizing sensors.

	▲	reactordev 5 days ago \| parent [-]
		Agreed :) It doesn’t make it any less 3d though. It’s the additive sensing of all sensors within a region that gives you that perception. Fascinating stuff.