How Many Blind Men Does It Take To Make An Eyewitness?
@Samuel Lacrampe started this thread: Principle Of Universal Perception wherein the claim was that the a perception is more likely to be real rather than a hallucination if there are a good number of people reporting that perception. The argument, to my reckoning, employs the well-know Occam's Razor, asserting that a perception being real is much simpler than what the OP calls "collective hallucination", a state of affairs in which a group of people reporting a perception are all hallucinating together.
This belief - that more the people reporting a perception the more likely that that perception is real - is universally accepted (as true) and applied in all occasions that involve perception. In addition to simplicity then, this belief is also justified by the improbability of a perception that is reported by many to be something peculiar to an individual like a hallucination.
It seems then that the rule that more reportings of a particular perception makes that perception more likely to be real and not a hallucination is well-justified by the two reasons I provided above. We should regard as real those things perceived by many people.
That said, what is of concern is this:
1. An individual/one person's report doesn't count as a strong enough foundation to believe that what this person perceives is real. How is it then that a group of people's report of a perception is taken as adequate grounds for believing a given perception is real? After all the group consists of individuals. It's like saying that a group of blind individuals can see even though each and everyone in the group is blind.
2. Let's do a simple mathematical analysis of this principle/rule. Suppose there are 3 individuals X, Y, and Z. They can perceive but they're facing the same difficulty as us in not being able to tell whether what they perceive are hallucinations or are real. We could then say, recognizing our predicament, that the probability that the perceptions of X, Y, and Z being real/hallucinations is 50% = 1/2. To assign any different probability requires justification why, something we lack.
Suppose now that X perceives something, say, P. The probability that X is perceiving something real = 50% = 1/2. The probability that X is hallucinating = 50% = 1/2. If X were now to come to me and report P then I would conclude that P is either a hallucination (50% probability) or P is real (50% probability).
Imagine now that Y and Z inform me that they too perceive P. If that's the case then the probability of X hallucinating and Y hallucinating and Z hallucinating is (1/2)*(1/2)*(1/2) = 1/8 = 12.5% AND the probability of X perceiving something real and Y perceiving something real and Z perceiving something real is (1/2)*(1/2)*(1/2) = 1/8 = 12.5%. In other words, the probability of all three (X, Y, Z) hallucinating is exactly the same as the probability that all three (X, Y, Z) are perceiving something real. This directly contradicts the belief that there's a higher probability that a perception is real just because more people report it.
Comments...
This belief - that more the people reporting a perception the more likely that that perception is real - is universally accepted (as true) and applied in all occasions that involve perception. In addition to simplicity then, this belief is also justified by the improbability of a perception that is reported by many to be something peculiar to an individual like a hallucination.
It seems then that the rule that more reportings of a particular perception makes that perception more likely to be real and not a hallucination is well-justified by the two reasons I provided above. We should regard as real those things perceived by many people.
That said, what is of concern is this:
1. An individual/one person's report doesn't count as a strong enough foundation to believe that what this person perceives is real. How is it then that a group of people's report of a perception is taken as adequate grounds for believing a given perception is real? After all the group consists of individuals. It's like saying that a group of blind individuals can see even though each and everyone in the group is blind.
2. Let's do a simple mathematical analysis of this principle/rule. Suppose there are 3 individuals X, Y, and Z. They can perceive but they're facing the same difficulty as us in not being able to tell whether what they perceive are hallucinations or are real. We could then say, recognizing our predicament, that the probability that the perceptions of X, Y, and Z being real/hallucinations is 50% = 1/2. To assign any different probability requires justification why, something we lack.
Suppose now that X perceives something, say, P. The probability that X is perceiving something real = 50% = 1/2. The probability that X is hallucinating = 50% = 1/2. If X were now to come to me and report P then I would conclude that P is either a hallucination (50% probability) or P is real (50% probability).
Imagine now that Y and Z inform me that they too perceive P. If that's the case then the probability of X hallucinating and Y hallucinating and Z hallucinating is (1/2)*(1/2)*(1/2) = 1/8 = 12.5% AND the probability of X perceiving something real and Y perceiving something real and Z perceiving something real is (1/2)*(1/2)*(1/2) = 1/8 = 12.5%. In other words, the probability of all three (X, Y, Z) hallucinating is exactly the same as the probability that all three (X, Y, Z) are perceiving something real. This directly contradicts the belief that there's a higher probability that a perception is real just because more people report it.
Comments...
Comments (54)
I'm particularly concerned about how, for example, when we perceive, let's say see, something odd, we look at our companion, if there's one, and ask, "did you see that?". The question bespeaks that we take the principle/rule, that more people reporting the same perception is a good indication that what's being perceived is real, seriously. But the principle, if I'm correct, is wrong.
Sometimes less is more. https://phys.org/news/2015-11-colour-blindness-aid-efforts.html
It's not a principle at all, but if something leads one to doubt one's senses, one looks for corroboration. I ask whether you saw that flying pig, because it is, as you say, odd. If it were normal, it would arouse no doubt and no comment, unless, 'Did you see that flying pig just now? I'd swear it was smoking a pipe!'
And you think you're the mad fool!
It is not an hallucination, but it is an illusion.
I can bring 10 people to a spot on a roadway during a hot summer day...and they will all "perceive" a reflective body of water way down the other end of the road.
It is not an hallucination, but it is an illusion.
How does that play into the calculation?
So what is the remaining 75%?
Do you think a person should corroborate what he's perceiving by checking how many other people also perceive the same thing?
Initially I thought this behavior is simply people seeking corroboration but it's not that because corroboration can and does involve stuff other than perception itself. For instance corroborating the perception of a fire includes things like objects near it heating up and catching fire, animals avoiding it (if it's too hot), etc. This is quite different from asking your companions, "do you see that fire?" as the question is specific to visual perception. In that, if my calculations are correct, people are mistaken because the probability of a perception's realness doesn't increase with the number of people reporting the perception.
Quoting Frank Apisa
An illusion is not the same as hallucination as the former is not a peculiarity of the perceiver/observer like a hallucination is. An illusion is out there just like reality is thought to be but isn't real (confusing) but a hallucination is in here as in something peculiar, "subjective" (?), to the perceiver. A magician can create an illusion but only the person himself/herself is responsible for a hallucination.
Quoting Outlander
All different combinations of X, Y, Z hallucinating or perceiving something real.
I asked Mrs un if you were saying what I thought you were saying, and seeking to corroborate what you're thinking with what I'm thinking, and she said "Stop being a twat, Mr un!" or words to that effect.
You'd have to trust your perceptions of what other people are perceiving, so ordinarily no. You need a reason to doubt a particular perception before seeking 'other evidence'. Mainly, things are as plain as the nose on your face, and if you seem to have mislaid the nose on your face, that is the time to consult your nearest and dearest.
So that takes us up from 50% to 75%? Was there not already a 100% chance of this with only X? Or perhaps that's your point. Hm.
Well a perception is an observation, inaccurate or not, false witness aside, it is real. Whereas a hallucination... well. Huh. Neat topic to say the least.
How would you differentiate a perception from a hallucination? There seems to be the idea that a perception is a possibly inaccurate or incomplete observation of something actually present vs. something that was not. Of course... wow what a paradox. :D
I guess I'd want to say the normal biological state is to not be hallucinating. So based on that the odds of several people doing so simaltaneously at the same time and place, absent of a hallucinogen, decrease with number.
But I speak from the bane of philosophy, the skeptic's point of view, someone who merely with three words, "are you sure?" casts everything we think we know - from factoids to facts - into doubt. Everything can be doubted, and in this discussion, doubt about perception is the issue.
Quoting Outlander
That is the issue.
Well from there, you have no more reason to believe any answer you might get, than the original perception. In fact there's no point my talking to you as you will dismiss it as 'mere perception'. In fact you don't even have a point of view, merely a point of perception. In fact... no, there are no facts, only perceptions. The perception that you or I are saying anything at all is... merely ...
Not necessarily. I sought the help of skepticism just to make the point that it isn't necessarily the case that we need a reason to doubt our perceptions. Everything can be doubted and that includes perception as per skepticism. However, skepticism doesn't claim that reality is a hallucination, just that it maybe and so we aren't making a mistake by looking for and evaluating good reasons to believe whether our perceptions are hallucinations or real.
And what, pray, does skepticism recommend we use to make this evaluation? Given that even if we find what we are looking for in the way of reasons to believe, they are just as dubitable perceptions as the perceptions we doubt, there seems no reason to do any such thing and that it is indeed a foolish mistake.
Look how we argue (in the logical sense). It reveals what we trust in - logic/reason. Surely then we can rely on logic to come to some agreement on the matter of whether more people perceiving the same thing increases the likelihood of our perceptions being real rather than just a hallucination.
Just your perception dude. I'm not even here, I'm just an hallucination.
:smile: Nothing in me that could hallucinate a man of such charm, wit, eloquence, and experience as yourself. It's impossible for a fool to hallucinate a sage for the fool simply does not know, and therefore cannot hallucinate, a wise sage.
Yeah, the Trump administration tells us this often.
They ask, "What are you gonna believe, you're lyin' eyes or what we tell you is so?"
Yes, it was an argument.
This is the broader issue - that of what the truth is, how we may know it to be so - that emerges from my concerns. Note, however, that my probability calculations are specific to perceptions only; I don't know to what extent they apply to other kinds of propositions.
Skepticism is not disprovable or so I hear. All that I wish to show you is our mutual trust in logic and thereby provide a platform for us to work our way to a solution for the issue we're discussing.
I read that. Seems to agree with my assessment of perception but for a different reason.
This is the problem with skepticism; the more I believe it, the less believable it is. But I have never met a skeptic yet who could follow this simple logic.
Yes I always rely on my non-senses, for proper evidence.
I'm not solipist or a skeptic just recognizing the limitations of eyewitness testimony and evidence.
That, you must be able to tell, is a contradiction. Not to be confrontational but just curious, why?
I suspect you rely more on your senses to read those instruments, though you probably don't remember.
Jesus, how hard do I have to press the Non-Sense button before the alarm bells start ringing?
Rely on your senses, or rely on your nonsenses - it's your call folks.
Which do you trust more in a murder trial an "eyewitness" or DNA that puts the accused at the scene holding the murder weapon? Just asking?
Knowing nothing else, indeed the probability of a true perception is 1/2, and a false perception is 1/2, and thus the probability of X, Y and Z all having a true perception is 1/8, and all having a false perception is also 1/8.
But we know something else: All three perceive the same thing P.
This new knowledge changes the probability. To simplify, let's suppose they can only perceive 10 different things ever. The probability of all three perceiving the same false perception P is now (1/10)*(1/10)*(1/10)=1/1000. Since the only alternative is a true perception, that probability is 1-(1/1000)=999/1000.
Hi. Sorry for the distraction. I'm sure you had better things to do.
You might want to take a closer look at what I underlined.
The probabilities of outcomes change based on your knowledge of the system. As the knowledge in the first paragraph above is different than the one in the second paragraph, the probabilities are different.
Indeed they do. Firstly, what exactly do you mean probability of a false perception is 1/10? As I mentioned before, any number other than 1/2 needs to be justified for it's assuming the very thing that has to be proven viz. it's more likely that a perception is true (your value for the probability of a true perception is 9/10).
Secondly, I'm not making any claims about the chances of perceptions being real/hallucinations apart from assigning it the reasonable value of 50% or 1/2 and assessing how increasing the number of perceivers affects this probability.
My interest lies in whether increasing the number of perceivers has any effect on the likelihood of a perception being real or hallucinatory.
Have a look below:
X: chance of perception being true/hallucinatory = 50% = 1/2
Y: chance of perception being true/hallucinatory = 50% = 1/2
Z: chance of perception being true/hallucinatory = 50% = 1/2
Chance that all three are perceiving something true = (1/2)*(1/2)*(1/2) = 1/8 = chance of all three hallucinating.
Adding more perceivers will not make a difference as the probability of a "collective hallucination" = probability of true perception.
I've made a boo-boo. Samuel Lacrampe is correct - the more people reporting a perception, the more likely is the perception to be real/true. The probability that everyone is hallucinating (collective hallucination) decreases with the number of perceivers reporting a perception.
Still in a fog I must say :chin:
Also I have edited my previous post: (1/10)*(1/10)*(1/10)=1/1000, not 1/100.
The probability that X, Y or Z is hallucinating/not hallucinating = 1/2 = 50%. By "not hallucinating" I mean the perception is real.
Notation: P(t) = probability that t is true, Hx = X is haullucinating, Hy = Y is hallucinating, Z = Z is hallucinating
1. P(Hx) = 1/2
2. P(Hx) & P(Hy) = (1/2)*(1/2) = 1/4. P(not that both are hallucinating) = 1 - (1/4) = 3/4
3. P(Hx) & P(Hy) & P(Hz) = (1/2)*(1/2)*(1/2) = 1/8. P(not all three are hallucinating) = 1 - (1/8) = 7/8
As you can see, as the number of people reporting a perception increases, the probability that all of them are hallucinating at the same time decreases.
However note the following:
4. P(~Hx) = 1/2
5. P(~Hx) & P(~Hy) = (1/2)*(1/2) = 1/4. P(not that both are perceiving something real) = 1 - (1/4) = 3/4
6. P(~Hx) & P(~Hy) & P(~Hz) = (1/2)*(1/2)*(1/2) = 1/8. P(not that all three are perceiving something real) = 1 - (1/8) = 7/8
The probability of a collective hallucination decreases with the number of people reporting a perception but that doesn't seem to translate into an increased probability that everyone is perceiving something real.
Please get back to me with your insights into the matter.
I either have an egg in my house, or I have some chocolate fondant in my house.
The principle of indifference gives both 50% odds.
I actually have neither.
So I have a 0% chance of having either.
You can't just throw probabilities out like that, you end up with absolute nonsense. If you want to apply the principle of indifference, it should make sense; not be applied over an arbitrary outcome set, you have to be super careful with it.
Your assessment is correct under the condition that we know nothing about the perceptions. It is equivalent at this point to guessing the results of tossing 3 coins.
But once we add the information that all three subjects always perceive the same thing, then the probability calculation changes completely. It is a lot more like rolling 3 dice, and knowing that the results are always 6-6-6, we are then inclined to believe that the dice are loaded.
The guys comment essentially was, "He did not lie. He just didn't tell the truth because he wanted to protect his son."
To be technical, all perceptions are real; it is a matter of finding if they are true or false.
I guess it's a question of how one uses the word "real". I meant to distinguish between hallucinations and its opposite, reality.
And the truth is we often believe what 1 person says. If you tell me you had a bad night's sleep and there is no reason for me to suspect you might have a motive for lying, I am safe, in general, taking such things as true. If you say you exploded into a mass of pulp and blood over breakfast this moring, I will want some more evidence than your account.
Depending on what is asserted and who is asserting it a single's person's account may be taken as true, possibly true, and every other gradation down to false.
Once we note that unlike blind people, fallible people can be often right, but this does not mean what we consider less likely need be accepted without more evidence, we have a very complicated situation.
The advantage of more observers is that some possible reasons for being confused, deluded, psychotic, start to reduce. This becomes even more likely (the reduction) fi the people do not know each other or have a common reason to make up/hallucinate/lie/misinterpret what they claim they have seen. Science tries to reduce all these factors with strict protocols.
You take one blind person and ask them what is in an image projected on a wall, then ask more blind people what they see, this does nothing to reduce their full on inablity to see. The exact same experiment, with a photo of a duck projected on a wall, reduces the factor of one person's fallibility in identifying the image. It's not a good analogy and it is not binary.
HOnestly, it seems like you didn't read what I wrote. I directly challenged the ideas that an individual's testimony has zero credibility and that the whole thing is binary. I don't think anyone follows these ideas in practice anywhere, regardless of their epistemology. Even the most rigorous scientist takes her husband's testimony, for example, on all sorts of things. Some things less, and if he said some things very little. But heck, I went into all of this in my previous post.
Yeah that's indeed what I thought you meant. I'm just being nit-picky.
For general info though, "truth" is "conformance to reality", where as "real" means "exists outside the mind (contrasted with imaginary)". As such, all perceptions, insofar that we experience them, are real. And if the info they provide conforms to reality, then the perceptions are true, and false otherwise.
Well, we are discussing the difference between hallucinations and reality. For a perception to be "real", the object of perception must be outside the mind and not something the mind creates.
Now if we are talking about scientific contexts only, again, individual observations are included in all research, but to gain acceptance as a theory, for example, rather than a hypothesis, we require more individual observations by individuals, and rigorous control of potential other factors. This is to reduce the potential problems an individual observer might have (misinterpretation, bias, mistakes). None of this reduces the single observer to having no value. That single obersvation simply does not have enough value (note!!!!! not binary, we are talking about degree of value). So when you add up things with not enough value in and of themselves,you are adding up some degree of value to a level considered rigorous enough to be consider ENOUGH value. Degrees of value.
If for some reason this is still unclear or you still want a video, perhaps someone else is a better interlocutor for you than I am.
Quoting Coben
The two excerpts above from your post don't square with each other. On one hand you claim individual perceptual testimonies are evidentially sound and on the other hand they're not and require extra support by way of additional perceptual testimonies of other individuals.
As far as I'm concerned if one person's perception can't be trusted, I don't see how a group of persons justifies a change in our level of trust; after all, the group is composed of individuals, no?
Quoting Coben
Why are you insistent about this binary-nonbinary issue so much. As I see it, either
1. a perception is real
OR
2. a perception is not real - a hallucination