I need to clarify. Quite a lot of 'scientists' are terrible at putting the scientific method into practice. I try to exclude those people from the category whenever possible. I do acknowledge, though, that this will frequently lead to confusion.

A lower IQ of scientists overall would make progress slower, but generally wouldn't impede the self-correcting properties of the method.

The so-called scientists who don't or can't put the method into practice would have their ability to make clever but specious arguments impaired. Possibly the reduced nonsense-sensing of the scientists would still be more than enough to identify and exclude the reduced levels of nonsense.

With reduced IQ across scientists and 'scientists' both, it's entirely possible that there would be more scientific progress for the field as a whole. There are a number of necessary but not sufficient factors involved, and non-lethal but cumulatively-damaging factors as well. It's not obvious to me that the properties measured by IQ are equally distributed across the positive and negative factors; I suspect they lend themselves to the negative more than the positive.

Annoyance had already explained his reasons for his position, and you explained reasons for yours in the rest of your comment. Once we are discussing those reasons directly, there is no need to use majority opinion as a proxy for the relative strength of those reasons.

This is a stronger modesty argument, as distinct from simply taking the majority opinion as one of the pieces of evidence for arriving at your own conclusion.

It is rational to weigh other people's opinions.

Logical fallacy: stating a contingent proposition as a universal principle.

Valid evidence of what?

Evidence is only valid or invalid in terms of the evaluation of related claims. What is being examined? That determines, in part, what is valid evidence to be considered.

Cherished falsehoods are unlikely to be random. In groups that aren't artificially selected at random from the entirety of humanity, error will tend to be correlated with others'.

There are also deep flaws in humanity as a whole, most especially on some issues.

Should we decide to believe in ghosts because most human beings share that belief, or should we rely on rational analysis and the accumulation of evidence (data derived directly from the phenomena in question, not other people's opinions)?

If we evolved ever more complex ways of lying, then we must also have evolved ever more complex ways of detecting lies.

Good point. Of course, that mechanism is for detecting other people's lies, and there is some evidence that it's specific to ideas and/or people you already disagree with or are suspicious of... meaning that increased intelligence doesn't necessarily relate.

One of the central themes in the book I'm working on is that brains are much better at convincing themselves they've thought things through, when in actuality no real thinking has taken place at all.

Looking for problems with something you already believe is a good example of that: nobody does it until they have a good enough reason to actually think it through, as opposed to assuming they already did it, or not even noticing what it is they believe in the first place.

"Lying" and "being wrong" are not the same. Lying is intentionally communicating a non-truth with the intent to deceive.

And intelligence doesn't necessarily have anything to do with our capacity to detect lies. You're simply assuming your conclusion in a different form. Again.

This criticism is valid if we think that the trait we vary is irrelevant to the effect we are considering.

No, the criticism is valid if we have no reason to think that the traits will be causally linked. You're making another logical fallacy - confusing two statements whose logical structure renders them non-equivalent.

(thinking trait is ~relevant) != ~(thinking trait is relevant)