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Invisibility - Ed's journal
One of the tropes in a TV show is that of the invisible man. It's quite a cool one, all things considered. But one thing's always bothered me about it - in order to be invisible, light has to pass straight through you, unhindered. Glass, for example, can be almost invisible - you see glass because of the dirt on it, or the fact that it's reflective.

But the problem is, your eyes. Your eyes absorb light, in order to feed it into your brain, to turn into an image.
So if you're invisible, you must necessarily also be blind. Because otherwise, the light isn't able to pass straight through you. Even with partial transparency, you'd only be able to 'see' in proportion to the amount of light you let through.

... or am I overthinking it?
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mrph From: mrph Date: August 29th, 2010 11:27 am (UTC) (Link)

Nope, not overthinking

I've seen it suggested in a couple of places. One of the antagonists in Warren Ellis' Planetary has precisely this restriction. :)
kalkyrie From: kalkyrie Date: September 1st, 2010 10:40 am (UTC) (Link)

Re: Nope, not overthinking

Oddly enough, the computer game Quake had this restriction as well. On picking up the invisibility power up, you disappeared entirely except for a pair of floating eyes (not quite as in depth as a book, but worth mentioning).
ed_fortune From: ed_fortune Date: August 29th, 2010 12:22 pm (UTC) (Link)
Best sort of invisibility combines 'being see through' with 'making you ignore the invisible person'. But yes, if you where invisible, you'd need a sight analog in order to be able to see.
warmage From: warmage Date: August 29th, 2010 02:30 pm (UTC) (Link)
Wife and I were discussing that construct after watching this most recent episode of Haven. If you're going to require all of the laws of physics to interplay then I imagine it may be as you say. Plot-wise, this could be overcome by having the invisibility based on an illusion, or mind-control (c.f. the Bugblatter beast joke).

On the "obey all the laws" side, The pupil is a relatively small aperture, and if the retina happens not to be reflective then allowing the thing to work normally isn't too much of a stretch; light comes in but it doesn't go back out. I guess that does require a bit of magical thinking to have a receptor that can be impinged by light but doesn't scatter it.

Also, invisible people can still be echolocated. Daredevil would tear 'em up. ;)
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sobrique From: sobrique Date: August 29th, 2010 04:38 pm (UTC) (Link)
Well, in that scenario you'd only be invisible from one direction - and you still wouldn't be able to see in that direction.
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From: portilis Date: August 30th, 2010 08:19 am (UTC) (Link)
Said technology actually exists, there's at least a couple of companies working on the development of it for military applications that I've seen.

It's a long way from being properly usable though...

On a different note, the "you can't see if you're invisible due to bending light around you" is actually in the rules for at least one rpg I know of (one of the mage versions).
wolflady26 From: wolflady26 Date: August 29th, 2010 04:49 pm (UTC) (Link)
You could have a type of invisibility that takes the light coming at you from every angle, and nigh-instantly projects it at the same angle on the other side of your body. Then, you'd only need your superpower to interpret the light coming from where you'd normally see to your brain.

With a system like that, you would actually be able to see in every direction, if your superpower were amenable.
phyrbyrd From: phyrbyrd Date: August 29th, 2010 10:13 pm (UTC) (Link)
Yeah, Cracked said something to this effect a while ago. I think the article was something along the lines of '5 Superpowers Ruined by Science'
phyrbyrd From: phyrbyrd Date: August 29th, 2010 10:15 pm (UTC) (Link)
Oh, hey, here's a thought. What if you yourself weren't invisible, but your power was in making other people's brains ignore you? A psychomanipulative power, as opposed to a physical one?
mrph From: mrph Date: August 29th, 2010 11:23 pm (UTC) (Link)
I've seen that one used well in various stories - it functions quite differently from 'traditional' invisibility, as it's no use against robots (or, in some cases, telepaths), but works fine against anyone with enhanced senses who wouldn't necessarily be fooled by 'real' invisibility.

Much more of a villain's power. Great for fun sequences with video recordings too - "but why didn't the security guard react when the guy in the costume walked right up to him... he wasn't exactly sneaking....".
phyrbyrd From: phyrbyrd Date: August 30th, 2010 03:27 am (UTC) (Link)
What good is a superpower if it doesn't have flaws? No flaw, no story. That's why Superman got ridicululous.
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