I've often seen creationists attacked by evolutionists on the basis that a "vast majority" of scientists accept evolution, therefore, we have good reason to believe that it is true.

Correct. The fact that virtually all of the world's top scientists and an overwhelming majority of scientists involved in life sciences believe that evolution is BY FAR the best theory that science has to explain the origin of species is an excellent reason to believe that the theory of evolution is the best theory that science has to explain the origin of species.

Although there are a few Christian scientists and lots and lots of lawyers and accountants and plumbers who disagree vehemently with those scientists, for some crazy reason I just assume that all those scientists probably know more about science than do all those lawyers and accountants and plumbers.

But I could be wrong.

That got me thinking, a few hundred years ago, the vast majority of scientists didn't believe in evolution.

Correct again. The theory of evolution (as opposed to scattered thoughts and disorganized beliefs about something like evolution) has only been around since Darwin published in 1859.

BTW, did you know that no one believed in Jesus 3,000 years ago, either? It's true.

So, the evolutionist who uses this argument must believe that the general consensus among scientists was wrong in the past.

Of course.

If this is true, it must at least be possible that the general consensus among scientists is wrong today.

. . . at least possible??? Of course, it's possible! It will always be possible for ANY theory of science to be mistaken. If it is not, then it is not a theory of science.

Have you heard of the principle of falsifiability? You should check it out.

BTW, how about Christians who argue that 2 billion people cannot be wrong when it comes to their belief in Christianity?

Since 3,000 years ago nobody in the world believed in Christianity, does this mean that Christianity back then was false?

At any rate, if you agree, then I would expect to stop seeing "But all the scientists say so" as an argument.

But why? All the scientists (or virtually all of them, especially the most expert among them) DO say so. And this is an important point.

You seem to misunderstand what it means to have a rational belief. To have a rational belief does not mean that our belief has to be absolutely true. To have a rational belief means only that we have good reason to believe the thing that we believe.

For example, it's plain silly to believe that a man 2,000 years ago literally walked across the surface of a lake. You cannot have a good reason to believe such nonsense and there are many reasons today to disbelieve it.

However, it's completely rational to believe that a man has walked on the surface of the moon because there are good reasons to believe that claim.

If you don't, then my question for you is, why are scientists so much more infallible now?

Since 'infallible' means INCAPABLE of erring or failing, how is it possible for a group of people to be more infallible than is some other group of people?

If one is infallible, then one is just as infallible as is any other infallible being and never more or less so.

No human is infallible; not Stephen Hawking or Steven Weinberg; not Jerry Falwell or Pat Robertson; and not even the men who wrote Matthew, Mark, Luke, and John.

BTW, how about Christians who argue that 2 billion people cannot be wrong when it comes to their belief in Christianity?

That makes 4.5 billion who claim that they are wrong.  

Correct. The fact that virtually all of the world's top scientists and an overwhelming majority of scientists involved in life sciences believe that evolution is BY FAR the best theory that science has to explain the origin of species is an excellent reason to believe that the theory of evolution is the best theory that science has to explain the origin of species.

Although there are a few Christian scientists and lots and lots of lawyers and accountants and plumbers who disagree vehemently with those scientists, for some crazy reason I just assume that all those scientists probably know more about science than do all those lawyers and accountants and plumbers.

But I could be wrong.

So, just for reference, 300 years ago you would have been a creationist?

If this is true, it must at least be possible that the general consensus among scientists is wrong today.

. . . at least possible??? Of course, it's possible! It will always be possible for ANY theory of science to be mistaken. If it is not, then it is not a theory of science.

Well I'm glad we agree on that at least :)

BTW, how about Christians who argue that 2 billion people cannot be wrong when it comes to their belief in Christianity?

That is exactly the argument I would NOT make in defense of Christianity, which is why I bring up this point in regards to an evolutionist's point of view.  Are you saying that the Christians who argue this have a valid point?

Since 3,000 years ago nobody in the world believed in Christianity, does this mean that Christianity back then was false?

I don't entirely agree with your premise, but I'll play along for the sake of the argument.  No, it doesn't.  But then you must apply the same standards for the situation I bring up.  If a large majority of people believe in evolution, that doesn't make it true either, right?

At any rate, if you agree, then I would expect to stop seeing "But all the scientists say so" as an argument.

But why? All the scientists (or virtually all of them, especially the most expert among them) DO say so. And this is an important point.

Because you just argued that what the majority of people believe at a certain time is no barometer of the truthfulness of it.

You seem to misunderstand what it means to have a rational belief. To have a rational belief does not mean that our belief has to be absolutely true. To have a rational belief means only that we have good reason to believe the thing that we believe.

I'm not arguing that believing in evolution is irrational, I'm simply trying to get someone to defend it on grounds other than, "Most people believe it."

For example, it's plain silly to believe that a man 2,000 years ago literally walked across the surface of a lake. You cannot have a good reason to believe such nonsense and there are many reasons today to disbelieve it.

However, it's completely rational to believe that a man has walked on the surface of the moon because there are good reasons to believe that claim.

I don't see how this applies to the topic at hand.  

If you don't, then my question for you is, why are scientists so much more infallible now?

Since 'infallible' means INCAPABLE of erring or failing, how is it possible for a group of people to be more infallible than is some other group of people?

If one is infallible, then one is just as infallible as is any other infallible being and never more or less so.

No human is infallible; not Stephen Hawking or Steven Weinberg; not Jerry Falwell or Pat Robertson; and not even the men who wrote Matthew, Mark, Luke, and Joh

I apologize; a poor choice of word on my part.  But you are ducking the question.  I will rephrase:  Why should scientists be so flawless now when we've already seen that they haven't been in the past?

So, just for reference, 300 years ago you would have been a creationist?

Yes, almost certainly, because given my personal circumstances (i.e., not a member of the educated aristocracy) I almost certainly would have been a Christian. We can believe rationally only that for which we have good reason to believe. It is extremely unlikely that I would have had good reason to believe that evolution is true prior to Darwin's life.

To have believed that evolution is true before Darwin thought and wrote would have required a ton of faith for virtually everyone who believed it just as to have believed that the earth is spinning on its axis would have required a ton of faith for the hoi polloi before Copernicus (the original, not ours   ). It's intuitive for us to believe that what our eyes and other sense organs seem to tell us is prima facie true, is actually true because it generally is true. It requires substantial evidence and strong argument to persuade us otherwise.

This (substantial evidence and strong argument), however, just oozes from the theories advanced by Copernicus, Newton, Darwin, Einstein, and many others. Those men did not accept the prima facie theories of how the world worked. They looked deeper into the nature of things, beyond mere superficial appearances, and discovered new truths.

Today, not to believe that those theories and similarly constructed theories are true requires a ton of faith.

This is excellent, Cop.  Then we agree.  Evolution should be defended on its own merits, not because a lot of scientists advocate it.

We do agree, but I think that Cogito was addressing another point--that what the majority of scientists believe, based on scientific findings, makes it a bit unreasonable to disagree with them in the absence of good reason.  I didn't see him as disagreeing with the idea that evolution should be defended on its own merits, and I suspect that you know he wasn't disagreeing with that point either.