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The Marvel superhero Daredevil is blind but has heightened senses, enabling him to perceive the world around him to a far greater extent than a regular person. In his depiction in the Netflix live-action series, he is able to tell the locations of everything around him, with fine enough detail to know if a person nods, when there are people approaching a building he is in, or if someone's heartbeat quickens.

This question is inspired by Daredevil and by the mathematical problem 'Can one hear the shape of a drum?', which is about whether the frequencies made by a polygonal drumhead are sufficient to determine its shape. Assuming arbitrarily good hearing, taste, smell and touch, and arbitrarily fast processing speed, is the sensory information that reaches Daredevil sufficient to determine information about his surroundings in such detail?

In a sense, does Daredevil 'only' need super-senses and super-perception, or does he also need magic?

If the superhero contextualisation puts you off, another way to frame this would be something like 'are the sounds, smells, tastes and pressure that reach a given location sufficient to predict the location of objects in the surroundings?'. In full generality the answer is obviously 'no' (since you can presumably create a safe sufficiently insulated that the rest of the room would be identical no matter what is in the safe) but I'm interested in whether this is a total bust or if there is something to it.

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  • $\begingroup$ In general, questions about superhero powers, movie special effects, and such make poor questions about physics. They are about stories, not reality. Questions of logic, consistency, reasonableness and such do not enter into this kind of story. In general there is no reasonable situation where reality matches the superpower or effect or whatever. $\endgroup$
    – mmesser314
    Feb 19, 2022 at 23:24
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    $\begingroup$ While this question is not allowed on scifi.stackexchange, and might sound awkard in physics.stackexchange, I think its is really well suited for worldbuilding.stackexchange! $\endgroup$
    – Arc
    Feb 19, 2022 at 23:48
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    $\begingroup$ @mmesser314 I've argued that before, but seems the community is fine with fictional physics questions. $\endgroup$
    – Kyle Kanos
    Feb 20, 2022 at 0:11
  • $\begingroup$ @KyleKanos - Thanks. I go back and forth on this. Many questions are asked by people who think movie effects are real and are asking how they did it. This is a considerably better question than that. This one is a bit more biology than physics. But at least is is in the direction of science. $\endgroup$
    – mmesser314
    Feb 20, 2022 at 2:50
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    $\begingroup$ Basically, you're asking what are the physics limits for a combination of a few sensory modalities. Whether it's phrased in terms of a superhero seems irrelevant to the quality to me. I don't have time to write a full answer, but would upvote one that: distinguishes passive (eg, listening) vs active (eg, sonar); perceptual precision vs complex scene analysis (probably where sonar would fail); speed advantages (hearing is fast, vision is slow, olfaction is slowest of all); etc. Personally, I think this is an excellent and appropriate question. $\endgroup$
    – tom10
    Feb 20, 2022 at 17:02

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Bats famously use echolocation to hunt for insects, but bats are sensitive to ultrasound. Human hearing tops out at frequencies around 20 kHz (or lower for middle-aged humans), for which the diffraction limit in air will be about a centimeter.

There are a number of living humans who can navigate by echolocation.

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There is a big difference between vision and hearing.

Vision is an imaging sense with very little spectral information. We can tell exactly which direction light is coming from. Add in triangulation, and we can build a $3$-D mental model of the objects around us. But we get so little of the spectral information that we can simulate it with just red, green, and blue.

Hearing is the opposite. Our ears are pretty good spectrum analyzers. We learn a great deal about the nature of an object emitting a sound by the spectrum. We can sometimes infer information about distance from the spectrum. But the only direction information is left or right. We have stereo music, but there isn't much point to adding too many speakers. We can move our head to get a little better. Essentially, we can play "Marco Polo" until our ears are right on top of the source.

Bats do better than humans for several reasons.

  • They work with higher frequencies. Shorter wavelengths means better localization.
  • Many animals have movable ears. Their ears are specialized to funnel sound in. They hear better if their ear points toward the sound. They know the direction from sensing the orientation of their ear.
  • Bats fly rapidly. This gives a lot of opportunity to triangulate. They have better distance information.
  • Sonar systems get distance information from time between emitting a pulse and receiving the echo. Bats emit a pulse, and can take advantage of this too.

No human can do very well at using hearing for navigation. Street corners emit sounds to tell the blind when it is safe to cross. They use different tones for east-west and north-south because our hearing has such a poor sense of direction.

Certainly no human can do what DareDevil does, or Japanese myths of blind swordsmen.

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