Wizardry

Quick counterexample to the idea that human belief is evidence to the nature of reality.

Most people think that we live in a world that is governed by flat, Euclidian geometry. Most people think that time and space or matter and energy are distinct entities. In fact, before Einstein, the most educated, brilliant minds in the world held the aforementioned beliefs.

The most patient observation of the everyday universe will not necessarily yield the most fundamental truths about space, time, matter and energy. Merely one century ago, claiming the preceeding ideas without rigorous proof would be tantamount to claiming the sky was green.

If common human perception cannot be relied upon to describe the observed phenomena in our universe, why then should it be the basis for our beliefs about phenomena (the origins of the universe and the existence of God) which are in principle unobservable?

The beliefs of the majority are of little, if any, value in determining the truth of important propositions. Galileo said of science, though I suspect it is also true of religion:
Peace out.

DarkBronzePlant

Oh, and one more: most computer users use Windows. What more evidence do you need that majority does not equal correct?

phlebas

Of course, the analogy doesn't really hold because there is an alternative to believing in God. Rumors about an alternative to Windows are erroneous

bd-from-kg

pug846:

Actually what I said was that it’s good evidence that X is true.

Since so many people here seem to be having trouble grasping this point, let’s consider another example. Adamson claims that a certain coin is rigged so that it will always come up heads. I flip it and it comes up heads. I say that this is evidence that Adamson is right. Obviously it’s not what one would call conclusive evidence: after all, if you flip an ordinary coin the chances are about 50-50 that it will come up heads. Nevertheless, if H is the hypothesis that the coin is rigged to come up heads and F(i) is the fact that it came up heads on the i’th flip, each F(i) is evidence that H is true, because P(F(i)|H) > P(F(i)|~H). In fact, suppose that the coin comes up heads 10,000 times in a row, and let P(i) be the probability that the coin is rigged to come up heads after taking into account the results of the first i flips. [That is, P(i) = P(H|F(1) ^ F(2) ^ ... ^ F(i)).] Obviously for any reasonable value of P(H) (the a priori probability that the coin is biased), P(10,000) is pretty close to 1. In fact, obviously P(1) > P(H), P(2) > P(1), etc., all the way to P(10,000). That is, each flip provides weak evidence that the coin is biased.

Now let’s take another example. Suppose Adamson claims that a certain roulette wheel is rigged to always stop on “23”. I spin the wheel; it stops on "23". In the same way as before, this is evidence that the wheel is rigged to stop on “23”. If we define P(i) as before, obviously P(i) will now approach 1 much more rapidly (as i increases). That’s because P(F(i)|H) is now much greater than P(F(i)|~H). Thus each outcome is strong evidence that the wheel is rigged because this outcome is much less likely than before under the “null” hypothesis (no bias).

So we arrive via a purely intuitive argument (no actual math!) at the result that an outcome that is very likely if hypothesis H is true but less likely if it is false is evidence that H is true, and the greater the difference between these two likelihoods the better evidence it is. (This can be demonstrated rigorously using Bayes’ Theorem.)

Now obviously the likelihood that a given proposition will be believed by the great majority of people is higher if the proposition is true than if it’s false. Formally, let B be the proposition that the great majority of people believe that X is true. Then clearly P(B|X) > P(B|~X). If this weren’t so – if false beliefs were just as likely to be widely believed as true ones - society would be impossible; in fact, humans would soon cease to exist. In fact, the differential is quite large: P(B|X) is much greater than P(B|~X). The fact that something is widely believed is such good evidence that it’s true that it is possible to get through life largely by simply believing what most people believe, whereas anyone who tried to muddle through by believing precisely what most people disbelieve would very quickly find himself dead.

Mageth, Wizardry, DarkBronzePlant:

All of you seem to be confusing evidence with proof.

Let’s say that Jones was murdered by poisoning. Smith had a strong motive; Brown had the means (he is known to have possessed the type of poison that killed Jones); Edwards had the opportunity (he is the last person known to have seen Jones alive.) Each of these facts is evidence of the guilt of the person in question, but obviously none of them is proof.

bgponder:

Of course professed belief is evidence of belief. If Fogerty claims to believe that President Bush is an alien from Arcturus and Grinwald claims not to believe it, the odds are far higher that Fogerty actually believes that Bush is an alien than that Grinwald does.

To all:

There’s such a thing as being too skeptical. Denying that something that obviously constitutes evidence of something is “really” evidence can only serve to discredit you by indicating that you are lacking in common sense.

If I were a prosecutor I’d hate to have any of you guys on the jury! If I didn’t have a videotape of the actual crime, not only would I not get a conviction, but all of you would insist that there was no evidence whatsoever that the defendant was guilty. And even if there were a videotape you’d probably refuse to convict. “Evidence? What evidence? Everyone knows that videotapes can be faked.” With this standard of what constitutes “evidence”, no one would ever be convicted.

However, as I said in my first post, what most people believe is not admissible evidence in a serious discussion of whether a proposition is true, for the reasons I explained there. It wouldn’t be admissible evidence even if what the great majority of people believed were true 99.9999% of the time.

[ January 07, 2002: Message edited by: bd-from-kg ]</p>

Mageth

Actually, bd-from-kg, if you read my post, you'll note that I said "I had no idea that believing in these things is evidence that they are true."

You said:

If I were a prosecutor I’d hate to have any of you guys on the jury! If I didn’t have a videotape of the actual crime, not only would I not get a conviction, but all of you would insist that there was no evidence whatsoever that the defendant was guilty. And even if there were a videotape you’d probably refuse to convict. “Evidence? What evidence? Everyone knows that videotapes can be faked.” With this standard of what constitutes “evidence”, no one would ever be convicted.

I have a hard time understanding how you came to this conclusion about me (or anyone else here) based on the posts we've made.

If I was on trial for a crime that I didn't commit, and the majority of people believed I committed the crime, I would hate to have you on the jury. Juries are supposed to make decisions based on factual evidence and not on opinions or beliefs (they can consider those things, but without "real" evidence they should not convict based solely upon them).

[ January 04, 2002: Message edited by: Mageth ]</p>

JB01

It seems to me that bd-from-kg's approach to calculating the extent to which the popularity of a belief provides evidence of its truth is valid, but only if we have no other a priori information about the truth value of the belief.

However, looked at from a memetic point of view, I think there is good reason to be more skeptical of many religious beliefs than of, say, beliefs about the capital of Ohio. From this vantage point, the beliefs that are most widely held will tend to be those that are best at passing themselves from one person to another. Since our "belief organs" are products of an evolutionary process, we can be expected to favor beliefs that confer some advantage on the believer, one subset of which is those beliefs that are true. But beliefs and belief systems that are neither true nor useful may also tend to spread if they have the right defense mechanisms - if they tend to create a real or imaginary penalty for their rejection, for example; or if they entail the rejection of the use of reason itself to discriminate truth from falsehood.

Since belief systems such as these (and Christianity clearly is one of them) will tend to become widely held irrespective of their truth, their prevalence has, I believe, less evidentiary value than that of widely held beliefs that are not self-supporting in this way.

99Percent

But then evidentiary (or evidential evidence) is a worthless argument IMO. How can you rely on something that is based on beliefs? And at what percentage to you draw the line?

I think there is a clear practical distinction between beliefs based on facts such as in criminal cases, and beliefs based on no real facts such as in theism.

jordan_tar

The only way to be too skeptical is to start questioning axioimatic matters. If I ask myself "Do I really exist?" "Does A really equal A?" - then I'm being too skeptical. I simply have no grounds on which I can argue against these propositions.

Your jury analogy seems to imply that we carry our "hyper-skepticism" over into everyday life, which is not true at all. It's important not to rely on authority of others when questioning religious matters and such - but if I'm at the video store, and I'm thinking of renting a movie, then sure I'd rather rent the one that everybody has said is brilliant than the one a few dilettantes rave about...it's just that sometimes it's okay to rely on what others have said, but in more important metaphysical matters, it's not.

critical thinking made ez

If you leave out the word "good", I could agree with this statement. But the minute you qualify the evidence as good, you have a problem with such a statement.

Good evidence means that the fact, which the evidence supports, is most likely true. You will have a hard time proving what most people believe is true most of the time.


By leaving out the word "good," you would have an automatic true statement. This small but important oversight may be what all the confusion is about.

In the same vain, I can make a true statment that says "The fact that the great majority of people believe X really is evidence that X is False.

[ January 04, 2002: Message edited by: critical thinking made ez ]</p>

DarkBronzePlant

I see what you are getting at. Simply put, then, I do not believe that "because most people believe it", or more correctly, "because most people in the U.S. believe it" to be credible evidence of the truthfulness of a proposition.

I'm not looking for proof here. In reality, there probably aren't that many things in which I believe and for which I have hard proof. I'm just looking for evidence. And I haven't seen any that's credible.