The "global warming" thread (and some others), together with reading the assessment results from my students for last semester, and preparing my courses for spring, really has focused me in on this question.

(By way of further background, this spring I will be teaching three courses: the intro econ course I teach almost every term; basic bus/econ stats; and an upper division course.)

Anyway, in setting up my courses, I like to think of them as having component. The first component, "content," which is where most people seem to focus in assessing and evaluating the course, IMO provides less than 10% of the course's value. Frankly put, if you make the content your criteria, you are going to be overpaying for my class. Buying a half dozen books and surfing the net for a hundred hours or so will yield just as much value.

The second component is about "learning to think better". Following one of my mentors, I like to label it "economics (or quant methods, or history) for citizenship".

All of which brings me to the question of the subject line. At the heart of thinking is the assessment of "evidence." Deciding what counts as evidence and what doesn't (the lawyers call this the "admissibility" criterion), and then deciding how much influence to grant that evidence ("the weight").

Now, the lawyers' rules of evidence also distinguish between evidence on the substantive facts of the case (who did what to whom, and for how much, if you will), and evidence going to the credibility of the witness.

I remember being amazed in law school at how much evidence that was supposedly "excluded" on the substantive question could still be brought in on a question of credibility. And it was done on the theory that the fact-finder (jury or judge) would then only weigh it on the credibility question, not the substantive one.

This bothered me for years, but it took a long time to pin down exactly why. (Not surprisingly, I turned out to be a lousy trial attorney during my brief sojourn into the world of legal practice.)

It was only sometime fairly late in work on the dissertation when I realized, in one of those epiphany moments, that I simply was not capable of reading, much less weighing, all of the evidence myself on whatever questions mattered to me. That my decisions about the credibility of other people would often be the determining factor as to whether I count what they present as "evidence" or not.

Hence my question for you: Since no one has time to read "everything" on a subject, how do you decide what evidence to believe and what evidence to not believe?

Or, to put it another way: how do you decide (i) whether you will always listen and give credence to what person X says; (ii) whether you will sometimes listen to what person X says; (iii) whether you will never listen to what person X says.

And, as an extra credit question for those of you still reading my rambling, what would you have me strive to teach others about dealing with credibility questions?

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Wow.....that's alot to think about.
To me, I listen to what everyone says. It has to be on an individual case I believe. What I mean is, just because so and so seems to be a nut case on one subject, doesn't mean you should automatically rule out whatever he or she says.
It's hard to put down in words exactly what I mean. For example, I might go round and round with someone on here about BF. I might disagree with them 100%. But that will NOT make me automatically ignore anything the person talks about. They might be really smart and onto something in other areas. And things like BF for eaxample, we make up our minds based on what little we really know about it. Some will back him 100%, no matter WHAT the guy did, some will bash him 100%. Me, I think he's MOST to blame with the situation, but not ONLY to blame. Of course we will NEVER really know the full details, as each side will slant it their way.
In cases like that, you can only go on what you know. BF saying on TV that he still could play, but didn't want to. And his statement that no one forced him to retire. Now.....we can go by that, but was he being 100% truthful? Was he planning all along to get on the Vikings team cause he didn't like it here anymore? Or was he just tired, and at the time really meant what he said? Again, all we can go by is his word. NONE of us knows the 100% truth of it, except BF himself.
(I only used that as an example cause all of us have dealt with it, and we have had many disscussions on it)
Now SOME things you can use as "evidence" are undeniable. For example, a dog never gives birth to a cat. No one has ever seen that happen. The sun always rises in the east, sets in the west. Could you for 100% sure say it ALWAYS has? No....cause you were not here since time began. But you can surmise it has by the fact that that's how it works now.

If you have dealt with people and had them lie to you before, that of course will make you more cautious in believing them in the future.

Not one of us knows EVERYTHING about ANY one subject. I myself will read both sides of an argument, then try to look at what I also see, and make judgements based on that.
I do that with things like "global warming". I look at what has been said in the past (like the fact that i was taught the next ice age was coming 37 years ago) and then look at what's driving the "bus". And who has to gain from it. That's how i came to my conclusions on that.
It's like that for any subject for me. I listen to what is being said, then "check" the person's past history as to how honest they are to me up to that point, how intellegent the person's argument is, and if possible, try to check other areas to see how what they told me matches up to scrutiny.

I think you should teach people to listen openly to anything someone tells them, and to do what I do. Don't automatically believe them, or automatically not believe them. To take what has been said, check it as much as you can, then make up your own mind as to what to believe.

I hope I made SOME sense. It's hard to put down on a page.

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Interesting question. To be honest I believe there is really no limit to what a person can know but by dissecting that knowledge and it's origin meticulously enough will render it useless, false or irrelevant. In life, for example, you live until you inevitably die, so what is the point of living? Any action you have completed, goal you have attained or any knowledge you have gained is moot or pointless. Yet people still find a reason for living and exercising any of these activities. People find a way to create a point for their living in any way possible, commonly dismissing any opinion but their own.

As a person who is open-minded or a "free-thinker" I believe there is no possible way to be completely free of opinion or live without bias. There is a selfishness encoded in our instinct to survive that no one can avoid.

Truth is in the eye of the beholder--it's merely a reflection of a person's perspective. A person that has no credibility to me can have an enormous amount of credibility to someone else. Because of this I tend to listen to whatever anyone says and interpret it however I decide to. There is no sense in being ignorant but everything you hear or see should be taken with a grain of salt. There is no one truth in the world because of the amount of differing beliefs, so how are you supposed to know who is right? Everything is relative.

The golden rule, "treat people however you want to be treated" describes a very peaceful tone of equality despite the fact that it's the same premise as the much more violent and vengeful "an eye for an eye."

There is no right in the world, only wrong, so I settle for just being content with myself and my surroundings and try to harm as few as possible. I also try to be simple and accept most science as fact, but even then I don't really trust anything one hundred percent.

Here's a question I used to ask a lot as a kid--"What if the same color I call green, is the same color you call green, but I see green and you see yellow?" Sure, I know it doesn't make much sense when you break it down but it's always answered a lot of questions for me.

EDIT: I guess I'm good at rambling too. And it doesn't look like I really answered your question either lol.

DCUBE!!!
I used to ask the SAME question! (About color)
We are TAUGHT what color is what, and call it that because it's what we are TOLD it is. But like you said, if I saw through YOUR eyes, i might say "That's not green, thats RED!"
I thought only I was goofy enough to think that way!!!LOLOL!!!

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LOL that's really funny. The fact that you're taught and told everything just goes to show how much of who are you is built in your childhood.

I will approach Wade's question from two different angles.

It is interesting Wade brought up the point of his economics syllabus, as throughout university, the first time I truly comprehended the fact that what we taught was not necessarily what was correct was in an Investment Analysis class in commerce. In this class, we were privy to countless (something like 500 pages worth - such a pain to read and memorise all of them!) journal articles dealing with investments using statistical measures - meta analysis, cross sectional linear regressions, trends and event studies; and behavioural finance (basically psychology in investing), biases, heuristics, etc. It is interesting to see how evidence from either spectrum can be treated as being correct.

As an engineer, it is simple for me to deal with facts. I put credence in something that can be scientifically measured over something someone tells me. Even so, it is often ironic how we formulate solutions which we can't REALLY explain, other than to say that it works. In either scenario, one must rigorously test the hypotheses or assertions within the evidence - naturally, either situation requires different forms of testing and are different in the believability criteria. The most obvious example I can think of is an example I had many years ago on memory retention.

Suppose, for instance, that you're a police officer at the scene of a crime. A hit and run victim is being rushed off in an ambulance. You have 3 witnesses, and in the interests of this discussion, I'll add a 4th - a traffic camera. Now I don't remember exactly what was stated by each victim in the example, but it went along the lines of, 1 typical pedestrian, 1 professional (some sort of accountant or something), and 1 child. The pedestrian gives an almost embellished account of what happened. The professional gives somewhat of a dry, facts-based account, but didn't see much of the accident. The child, naturally, can say barely more than how the person was hit by a car and laid still for a long time. Lets say the traffic camera caught the car speeding through an intersection. So we have 3 situations of evidence based on what people saw, and 1 based on what a camera saw.

Of course, most people would naturally put credence in what the professional saw - the opinion was most objective. But that isn't to say that the evidence is most accurate. The colour of the car, for instance, may have been mistaken. You'd cross-examine witnesses for details to remove the possibility of error in human memory retention and psychological biases. You'd probably discount the child's evidence, or only use it to verify facts from the other two. For the camera, you'd ensure that the picture was taken right after the accident and that the camera was working properly. Different testing for different forms of evidence.

I've only done two units on law, so I can't particularly speak much to do with discovery, admissibility and/or exclusion of evidence. I would think it's a matter of civil vs criminal case, whether the evidence is material, whether a witness is reliable, whether the evidence was obtained legally or illegally, etc, in addition to the reliability of the evidence itself.

So I believe it is important for people to separate that which is evidence based on factual statements, and evidence based on heresay, conjecture, opinion, etc. You'd then test how reliable the evidence is. If it's based on facts, I can (or read how others) test the evidence using rigorous testing procedures or testing the counterargument. If it's based on conjecture, I would question the person to see how strong his/her convictions are, and whether they display any forms of psychological biases which cloud their opinion. Then, as it always is, it's a judgement call. So that's how I approach things.

In a nutshell, to answer Wade's 3 short questions, I'd ask myself whether I know anything currently which conforms or conflicts with what X is telling me (test the evidence), why I should be listening to X, and why I shouldn't be listening to X (test the person). And even then, it doesn't hurt to get a second opinion.

I just re-read what I wrote. Man, I rambled on a lot.

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I invariably find the small dents and scratches in my car when I wash and wax it.


My step-mother's ex-husband's father had an even more profound philosophy. ("Daddy Buck"- he also introduced me to-and was the progenitor of- my hatred/strong aversion to-chewing tobacco---"Ol n word hair" was his brand-really--"twist 'baccy"--This was in rural Virginia---I was 12, but you remember shit like that-painting the "picture"- hopefully)

I asked him once about his next door neighbor. (The neighbor shoo'ed me off his property while squirrel hunting). He told me that his neighbor was a thief and a liar. I asked him why he felt like that. . He told me that his neighbor borrowed a rake 30 years ago and had not yet returned it. He was still waiting for his neighbor to do so, and until that rake was back in the barn, his assumptions hold true.

I always liked 'ole Bert's philosophy...

"If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it.
If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence.
The origin of myths is explained in this way." - Bertrand Russell