Why should evolution be accepted on authority?

Excellent topic, Robin. I agree with most of what has been written in response (well, except Mike's, obviously). The question you finished up with: "Why should we trust such people?" is the heart of the issue. Para mentioned "because it works", but I'm not convinced that's the whole answer, although I'd say it's probably a significant part.There IS a danger in accepting the word of anyone, scientist included, for a claim (i.e., accepting on authority). As PaulK and others pointed out, errar humanum est. Even several scientists can agree with each other, but still be wrong. For instance, I'm currently re-reading some of the controversy over the bolide-impact-as-cause debate surrounding the Permian-Triassic mass extinction (okay, so, I have no life. Everybody has a hobby — extinction is mine ). A fair selection of scientists accepted the report - many others did not. A decade more data later, it appears a bolide probably wasn't implicated. So the likliehood now is that those who originally supported the hypothesis were wrong: there are other explanations for the data.Where does this leave the rest of us? I mean, I’m not a geologist and most of the evidence for the P-T bolide is geological. How do I evaluate the claim and avoid jumping on the bandwagon simply because some group of scientists make a statement — or even published a paper in Science (as was the case here) without having either the background expertise to directly evaluate the data, or the time/resources necessary to go to Japan and elsewhere and look at the rocks myself? I submit that ANY claim can be evaluated by anyone who wants to take the time to do it: even, on occasion, without esoteric knowledge.The following six rules are adopted and adapted from an essay by James Lett, A Field Guide to Critical Thinking, originally published in Skeptical Inquirer (Winter, 1990). It is by far and away the best guideline I’ve encountered, and one I personally use repeatedly.1. It must be possible to conceive of evidence that would prove the claim false.2. Any argument offered as evidence in support of any claim must be logically sound and valid.3. The evidence offered for a claim must take into consideration all available evidence.4. Evidence offered in support of a claim must be evaluated without self-deception.5. An independent observer, under the same conditions and circumstances, must be able to achieve the same results.6. The evidence offered in support of a claim must be adequate to establish the truth of the claim.There’s a corollary to rule 6 that directly addresses the authority issue: evidence based on testimony and/or recourse to authority is not sufficient to prove the truth or falsehood of a claim.The idea is that if you can subject a claim to all six of these rules, and it passes, then you’re reasonably able to state with some confidence the claim is true. It doesn’t guarantee the truth, however. Disconfirming evidence might be found tomorrow that throws the whole thing out the window. YOU don’t have to re-perform the exact observations or experiments, but YOU can and should apply critical thinking to the claims — regardless of who said it.

An excellent question. How DO we (i.e., the unwashed masses), know whether a scientist is including all available evidence? Lithidod-man and Trixie both mentioned the answer: you have to be willing to dig through the literature. Even if you don't necessarily understand the argument, you can at least see if there are dissenting opinions. In that case, you are justified in withholding acceptance of the claim. One of the dissenting opinions in the P-T extinction debate, for example, noted that one of the rock formations used in support of the claim didn't actually contain rocks from the boundary date. I don't have the first clue HOW they determined that, but the fact that someone called into question something so fundamental to the claim justifies my unwillingness to accept the claim as valid until/unless this anomaly is rectified or explained.There are really two things to consider when you or I (as card-carrying members of the Great Unwashed Masses - GUM) are asked whether or not we accept a claim:1) what is the nature of the claim? IOW, is it an everyday claim or is it an extraordinary claim? For example, if I say that it's snowing today where I live, there's no real reason to doubt my "testimony". After all, it's December and winter in the Northern Hemisphere. Assuming I live far enough north where snow is possible, you can probably take my word for it - the claim isn't outside the realms of possibility. You may have other reasons to doubt it (i.e., I'm a known pathological liar, or somesuch), but absent that extra information, you can accept my claim at face value. OTOH, if I claim that I was kidnapped last week by aliens and taken to the far side of the moon for bizarre medical experiments, you are fully justified in demanding that I provide substantial evidence for the claim. It's the old "extraordinary claims require extraordinary evidence". If someone attempts to overthrow the reigning paradigm, then us GUMs are justified in demanding they provide quite extensive evidence to support the claim before we take it as valid.The second issue is: us GUMs actually know way more than we think we do. Any moderately intelligent person does. It never ceases to amaze me how accurate my intuition can be (it can also be wrong, of course ) when examining some scientist's claims - or the claims of politicians, advertisers, writers and others of that ilk. If the claim raises doubts in your mind - even if you can't put your finger on precisely what is wrong - then your intuition is attempting to tell you something. At that point, you need to start asking questions. Where do the claimant's facts or figures come from? Does the claimant have first-hand knowledge or experience? Is the claimant using logic or appeals to emotion when presenting their case? Was the study/book/report published in a generally reputable source that has published validated works in the past, or is it a fly-by-night self-publisher or known crank journal? Does the claimant reference other works - and can these be checked for relevancy and timeliness? Do other works reference the claimant's work (an interesting way to see what OTHER poeple think about it)? Has the claimant made his/her original data available to other people in his/her field? Is the evidence presented objective or anecdotal? etc etc. You get the idea.Ultimately, it may come down to simply accepting a claim at face value - but being willing to reject the claim if new/contrary evidence is presented. You're not bound to defend-to-the-death a claim you accept if it is shown to be wrong. It's not a contract (as someone noted). You're allowed, and even encouraged, to change your mind as the situation changes. Even "no opinion" is a valid answer to a claim you're uncomfortable or unsure about.Hope this answers your question.