You raise a good point, Eytanz, and it is indeed a conundrum. If I am not an expert myself, then how can I be qualified to criticize the opinions of an expert? A layman cannot understand the reasons behind an expert's opinions.
That is certainly a valid point in many situations. I would contend, however, that its application is limited by several factors.
1.) The esoteric sometimes intersects with the mundane. A perfect example is of a traveller who has been to the distant country of Zababi, a country about which I know nothing at all. I will have no cause to doubt him if he tells me that people in Zababi are shorter than people in America, that they eat mostly beef, and that their women wear copper jewelry. He’s been there. I haven’t. He would know. But if he tells me that people there have three eyes, then I will begin to question, because that does not accord with what I do know about human physiology.
When the expert is speaking on topic that does intersect with my experience, then I have no option but to trust him. But if the expert’s words have implications in areas that are familiar to me, then I do have some power to judge his claims, even if his field is generally mysterious to me.
2.) Logic is logic. If an expert contradicts himself, draws conclusions not supported by his evidence or otherwise makes logical errors, then anyone can criticize.
Going back to my traveller, if he tells me on one day that the Zababians are monotheists and on another tells stories about their pantheon, then I can reasonably conclude that not everything he’s told me is true. I can conclude this even though I don’t know anything about Zababi.
Similarly, I can spot erroneous conclusions. He tells me that the Zababians eat cats. I ask how he knows. He says he knows because his cat vanished mysteriously from his hotel room. I say that’s not enough evidence to justify the conclusion that all Zababians are cat eaters.
3.) Ulterior motives are sometimes apparent. When an expert stands to gain personally by making the claims he is making, then suspicion is automatically aroused. For instance, if our traveler tells us that the Zababians are dangerous conquerors who are libel to attack my city and at the same time opens a gun shop, then I might suspect that it’s a marketing scam. Again, my suspicion is justified even in ignorance of Zababi.
4.) There’s probably a 4, but I can’t think of it at the moment.
That's if I know nothing. Of course, if I do know something about the topic at hand, then my ability to criticize increases. So, while it is sometimes true that a layman is not qualified to question or critique an expert opinion, there are definite and not uncommon times when he is.
