How do you prove photography to a blind man?

That was the question I was asked: how would you prove to a blind man, that photography exists?

I knew what he was getting at. We had been discussing psychics. He was a firm believer in psychic powers, had had psychic experiences, and regularly visited a psychic. His point was, since I had not experienced psychic powers, I would never be able to believe in what he “knew” to be true. You could never prove to a blind man that photography exists, and likewise no one would ever be able to demonstrate to me that psychic powers were real.

It took me about ten seconds to think of a way to show he was wrong. This is what I said. Give the blind man a camera, a tripod and a remote shutter release. (Ideally the camera is a Polaroid, or a digital with an instant picture facility.) Everyone leaves the room but the blind man. He takes a picture of himself, and holds up a number of fingers (1 to 5) at random. The sighted person comes back into the room, looks at the picture and says “you were holding up X fingers”. If he gets the right number, and continues to do so every time this experiment is performed, the blind man will eventually conclude that photography is real. Technically, he will conclude the hypothesis that “a camera can record a visual image”, might be true.

He will want to repeat the experiment with different rooms and different sighted people. He will want to tighten his controls to make sure no one can see through the window or the keyhole. He will want other blind friends of his to do the same experiment successfully. But essentially, he will be convinced by this method.

The believer went quiet. (It must be annoying when your analogy is turned against you.) But I decided to push it further. I wanted to ask him some questions.

My first question was, if you did this 1,000 times, and the sighted person got the correct number of fingers (say) 225 times out of 1,000 (where pure chance would be 200 times), would the blind man believe that this “anomaly” was proof of photography? Wouldn’t he expect nearly 1,000 correct out of 1,000? What if when the controls were tightened, the result was reduced to close to 200 correct – pure chance? What if the sighted person was found to have cheated?

What if the blind man had to do a drawing and hold it up in front of the camera, instead of his fingers? The sighted person had to write down what he thought the drawing was of, and then a judge got to grade the description based on the photograph of the drawing? Say the blind man drew a circle and the sighted person thought it was a tree, and the judge rated that 7 out of 10 because a tree is roughly circular? Would the blind man be convinced?

What if the blind man had to select one drawing from four “targets” and hold it up in front of the camera, instead of his fingers? The sighted person is shown the four targets and asked to rate the degree to which each matches the one in the photograph. If the sighted person assigns the highest rating to the correct target, it is scored as a "hit." If the sighted person gets a hit, say 35% of the time (when chance would predict 25%), would the blind man be convinced? What if the person running the experiment was in the room when the photo was taken, and prompted the sighted person during the judging process - would the blind man be convinced then? What if numerous other experimental errors were noted?

What if a scientific body spent 25 years researching whether sighted people could guess how many fingers blind people were holding up in front of a camera, but concluded that there is ultimately very little, if any data that support the hypothesis that they can?

What if a conjuror offered one million dollars for any sighted person who could successfully perform the five finger test, but no one was able to do it?

Wouldn’t the blind man say to all this, “why can’t you just tell me how many fingers I’m holding up?”

The guy didn’t want to answer. He conceded his analogy was about me not having had a psychic experience. But apparently the analogy didn’t apply if I turned it around to his beliefs.

And they say skeptics are closed minded.

Post Script

See my post Pretty Soon for a lighthearted look at the history of parapsychology.

March 18, 2005 in Paranormal and New Age | Permalink

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It just occurred to me that you don't have to limit yourself to tests involving numbers of fingers. The blind person could use the tripod-mounted camera to take a pictures of a series of objects with a digital camera or Polaroid, and then the sighted people would have to identify them. You could also have the blind person write things down and photograph the paper. The possibilities to "prove" the existence and function of photography are endless.

Posted by: Orac | March 19, 2005 at 08:59 AM

Really interestiung post, great response, great links. Through homework.

Very much pertains to many a skeptics challenge.

Posted by: mad house madmadn | March 19, 2005 at 09:41 AM

And in some of the photographs the man's hand is turned sideways to the camera, or is out of the frame of the photograph, so the fingers can't be counted. Sometimes the shutter doesn't realease properly, or the camera is out of film, or a moth lands on the lens aperture. Or the blind man doesn't trust that the sighted people haven't set up hidden peepholes to watch him hold up his fingers, so he insists on holding the experiment in his own apartment, which happens to have no lighting. Maybe he opens the camera and exposes the film. Or puts his hat on it. There are a lot of ways to wreck a photograph, and it's a pretty simple process that we understand.

And he scoffs at the "you weren't in the right place" or "look it doesn't work without light!" explanations the way we scoff at the psychic bemoaning uncooperative spirits or negative energies introduced by the experiment.

There is no denying that there are hundreds of fake psychics. Heck, I wrote a horoscope column once, and I just made them up. If there is anything to psychic phenomena, no one, including the psychics, knows how it works, so we have no idea how reliable it should be, hw to ensure the film is loaded correctly, or what would affect it. It's akin to someone taking photographs who doesn't know that there is a camera in the room or how to operate it, but has discovered that if you dance in certain ways, sometimes an image appears. The image only appears if someone happens to have left something on a high shelf and the rhythm of the dance happens to knock it onto the camera shutter button without knocking over the camera.

The blind photographer is an argument against the existence of psychic phenomena, but not a conclusive one because the metaphor itself suggests explanations for the unreliability of psychic phenomena.

Posted by: Qov | March 26, 2005 at 09:00 AM

And in some of the photographs the man's hand is turned sideways to the camera, or is out of the frame of the photograph, so the fingers can't be counted. Sometimes the shutter doesn't realease properly, or the camera is out of film, or a moth lands on the lens aperture. Or the blind man doesn't trust that the sighted people haven't set up hidden peepholes to watch him hold up his fingers, so he insists on holding the experiment in his own apartment, which happens to have no lighting. Maybe he opens the camera and exposes the film. Or puts his hat on it. There are a lot of ways to wreck a photograph, and it's a pretty simple process that we understand.

Why don’t the sighted people explain these problems to the blind man? Can’t they teach him to take better photos? Why don’t photos get any better with time and experience? The results should get better with time. Real photography has improved many times compared with when it was first invented. Same with all new technologies. Photographs in this analogy world get no better with experience. Why not?

And he scoffs at the "you weren't in the right place" or "look it doesn't work without light!" explanations the way we scoff at the psychic bemoaning uncooperative spirits or negative energies introduced by the experiment.

But if he follows the instructions of the sighted people, these problems will diminish.

There is no denying that there are hundreds of fake psychics. Heck, I wrote a horoscope column once, and I just made them up. If there is anything to psychic phenomena, no one, including the psychics, knows how it works, so we have no idea how reliable it should be, hw to ensure the film is loaded correctly, or what would affect it. It's akin to someone taking photographs who doesn't know that there is a camera in the room or how to operate it, but has discovered that if you dance in certain ways, sometimes an image appears. The image only appears if someone happens to have left something on a high shelf and the rhythm of the dance happens to knock it onto the camera shutter button without knocking over the camera.

Why would the number of “hits” improve if the blind people drew pictures and got judges to determine how close the sighted person was to what the blind person drew? Why, when they just hold up a number of fingers, are the results close to chance? Why is only that that when ambiguity is introduced (subjective “judging”), that we get hits above chance? And why is it that whenever some one experienced in spotting trickery is present, the camera stops working?

The blind photographer is an argument against the existence of psychic phenomena, but not a conclusive one because the metaphor itself suggests explanations for the unreliability of psychic phenomena.

I never said it was. But then it’s not my job to prove psychics aren’t real. If someone wants me to believe psychics re real it is their job to provide evidence they are. The burden of proof resides with the claimant.

Posted by: Skeptico | March 26, 2005 at 12:01 PM

Fandamntastic....

I bookmarked this.

It's my Circle in two weeks; hope to hear from you.

Posted by: Steve Snyder | March 31, 2005 at 10:28 PM

Do the psychics themselves claim to know how the phenomenon works? Perhaps we're all blind, but some make a habit of stumbling across the shutter switch.

If psychic phenomena do exist, what we're getting is unpredictable glimpses.

When we don't know how something works, who is to say that the presence of a skeptic, or of measurement equipment, is not as detrimental to the process as trying to take photographs in the dark.

Posted by: Qov | April 06, 2005 at 11:23 PM

Do the psychics themselves claim to know how the phenomenon works? Perhaps we're all blind, but some make a habit of stumbling across the shutter switch.

If we’re all blind, what would be the point of photography? Would it matter if it was real or not? No one would be able to use it, would they?

If psychic phenomena do exist, what we're getting is unpredictable glimpses.

Or, psychic phenomena do not exist. Ever heard of Occam’s Razor?

When we don't know how something works, who is to say that the presence of a skeptic, or of measurement equipment, is not as detrimental to the process as trying to take photographs in the dark.

I don’t have to know how photography works to take a photograph. And you have not answered these questions:

• Why would the number of “hits” improve if the blind people drew pictures and got judges to determine how close the sighted person was to what the blind person drew?

• Why, when they just hold up a number of fingers, are the results close to chance?

• Why is only that that when ambiguity is introduced (subjective “judging”), that we get hits above chance?

• And why is it that whenever some one experienced in spotting trickery is present, the camera stops working?

Well?

Posted by: Skeptico | April 08, 2005 at 03:58 PM

Okay, let's drop the photography analogy as it can seem confusing. The basics are as follows: Photography is a scientific and mechanical process that follows pre-disposed and understood laws of physics that the creators of the experiment and the participants both understand. Psychic phenomena, on the other hand, is not a science and not a mechanical process. It doesn't appear to follow the pre-disposed and understood laws of physics, and the creators of these experiments (and perhaps the participants themselves) don't fully understand the phenomena they're trying to quantify.

Therefore: Using science to prove the existence of psychic phenomena is largely impossible, as is using science to disprove it (though a skeptic will invariably argue that the burden of proof clause doesn't require them to... which is true). Science and Mysticism are separate issues, one relying on the burdens of proof the other relying on the presence of faith, and trying to mar or mix the two is apologetics at best and pure hokum at worst. Just my two cents.

Posted by: Cuindless | October 27, 2005 at 05:12 AM

Psychic phenomenon can be scientifically proven, depending on your response to this:

True or False: Psychic phenomena have observable effects.

Posted by: BronzeDog | October 27, 2005 at 06:44 AM

Can't prove psychic phenomenon? I call bullshit. Huge steaming piles.

Move my coffee cup from my desk to yours using your mind.

Remote view what I had in an envelope on my tv.

Give me EXACT details on where to find Natalee Halloway.

Tell me my great-grandmother's maiden name.

Posted by: Rockstar | October 27, 2005 at 07:42 AM

The eyes don't see, the ears don't hear. If we believe we see ghosts, if we believe we hear the dead talking then we will.

If we believe in Physics then we will be happy when they’re accurate 20% or less of the time. Our brain is very accommodating to our beliefs. It will accept all kinds of garbage as proven facts if these facts will justify our beliefs.

Take religion for example! Anybody got a camera?

Posted by: daffeyD | January 28, 2006 at 09:16 AM

if everyone in the world was blind would the stars exist---the answer is no because we would have no knowledge of stars so they would never exist. also time would not exist either, so this is where the observer comes in the stars exist because we looked up, time goes on because we check our clocks

Posted by: crazynoc | April 23, 2006 at 05:22 PM

crazynoc is, of course, crazy. In a world of the blind, the stars would still exist, and they'd still produce electromagnetic radiation. We just wouldn't have convenient EMR detectors in our heads. Time would still exist, though we'd have a few markers up in the sky become less convenient as a result of blindness.

Posted by: BronzeDog | April 24, 2006 at 06:06 AM

(Yawns). Not that old turkey about "science cannot possibly prove psi phenomena". This usually comes from people who don't know a thing about how science works.

Yes, once, scientific instruments couldn't detect X-rays, but they can now. Not because some mystic just claimed they existed, mind you.

Yes, once some scientists said heavier than air flight was impossible. Now, we zoom about at 30,000 feet and 600 m.p.h., but not because of a woo-woo claim that it was possible: scientists just looked a little closer at the workings of the world.

As far as I'm concerned, if psychic phenomena have real, tangible physical effects, then why on earth can a real, tangible scientific instrument not detect them?

I can't remember the scientist's name, but I love his quote: "No, we don't know everything. But at least we're working on it!"

Science is not a fixed dogma carved in stone. It's not a set of immutable rules. It's a way not to be fooled easily.

The weird brigade cling to immutable rules like a security blanket, always with the same anti-science mantra.

What I want to know is, where are the psi-powered cars and planes that will free us from fossil fuel pollution? Nowhere?

Pollution-free products may well be on the way, but you can bet it's scientists who are working on them.

Posted by: Big Al | April 24, 2006 at 07:23 AM

Big Al covers a lot of points better than I could.

I find it funny that people often accuse science of ignoring the invisible, when it's very well suited to detecting the invisible. I've looked at color infrared photographs. We can't see near infrared with our occular orbs, but we can use it to detect diseased plants. We can use far infrared to see in the dark. We can use X-rays to see inside people. We can detect gamma ray bursts to learn about the nature of the universe. We can use radio and microwaves to communicate with each other, like when I'm on my wireless laptop.

And that's just the electromagnetic spectrum. We can observe in other ways. We can simply count the number of psychic predictions that come true under controlled circumstances. The answer is, of course, roughly equal to chance.

One typical response I've seen to that is to make psi powers weaker and weaker, requiring more and more trials to detect. Science is so good at detecting subtle things, it's gotten to the point that these people should start asking themselves if something so weak is worth all the fuss.

Posted by: BronzeDog | April 24, 2006 at 09:08 AM

Good points Bronze dog and Big Al. It reminded me I wrote earlier about the excuses for why there is only weak evidence for psi.