Experts, even with rows of initials after their names to prove it, consistently know less than they pretend or believe that they know.
You cannot judge how much an expert knows by what he chooses to tell you – only by what he answers to your questions. The first is under his control, the second is not.
Go to an expert with some questions for which you have researched the answers. If your future depends on his knowledge you are entitled to test it first.
Never go to an expert for advice without knowing more about your problem than he does. But it is more tactful to spare him the benefits of your instruction. Like the waiter he can always spit in your soup.
Never forget that doctors and lawyers used to use the tradesman’s entrance. Anyone to whom you pay a fee, directly or through taxation, is at your service. You have more interest in the health of your body or your rights than he has.
A professional is someone who uses particular skills for your benefit ahead of his personal interests. By that definition a plumber may be more professional than a lawyer.
secondsightblogdotnet 
The problem is especially acute with scientists. With some experience in the ‘industry’, I can safely say that scientists are no more worthy of respect than anyone else (OK, well maybe a little).
When you’re a newly-minted graduate, you don’t go against the opinions of your supervisor/s, if you want your career to continue;
When you’ve got your M.Sc or Ph.D., you follow the money – no-one does research in areas that the moneybags won’t fund (while their reasons for not doing so are seldom unquestionable);
Only at very senior levels is there much freedom to question conventional wisdom – and by then you’ve built your career on the establishment, so why would you?
As an example, consider how long it took for Continental Drift to be accepted as fact.
All of which should give us pause when Ayatollah Dick Dawkins starts ranting about how Only Science Is The Source Of All Truth; and when Al gore starts gushing about climate change (for the record, as a former palaeoclimatologist, I can safely say we’re not nearly as important as we think we are).
Scientists have a herd instinct that makes sheep look like independent thinkers.
It is true that it took a while for Alfred Wegener’s ideas to be accepted. When they were, however, plate tectonics suddenly became the new orthodoxy, as I well remember from my Sixth Form study of geography.
This is the kind of event that sociologists of science call a ‘paradigm shift’. The Copernican Revolution, the overthrow of the phlogiston theory, the work of Faraday and Maxwell, are all instances of such shifts.
I think that James H. is being rather negative and cynical about both science and scientists. I don’t think scientists are all bad, and I don’t believe all science is tainted with neo-Promethean ambition (thinking of Mary Shelley’s ‘Frankenstein’).
As for climate change, I am firmly in Al Gore’s camp, and in agreement with the IPCC. The percentage of CO2 and other ‘greenhouse’ gases, such as methane, in the atmosphere is increasing. This is down to human activity, because we are burning such large quantities of fossil fuels, releasing all that stored Carboniferous Period CO2 back into the 21st Century atmosphere. The consequences will be as dire as predicted unless we do something about it soon – but will we?
The relationship between professional and client is a two-way responsibility. Humility is required on both sides. Each has to earn the trust of the other. The professional must tell the client what the client needs to know, rather than what the client wants to hear: and he must not conceal doubt or ignorance. The client must tell the professional what the professional needs to know, not just what the client thinks is relevant, or wants to disclose. The client will usually be ill-advised to assume that he understands his problem better than his advisor: he may know the facts, but he will lack the background and context that a good advisor can give him. “All cases are unique, and very similar to others”. There are bad advisors, as well as bad clients: clients have no duty to stick with the former, but advisors must do their best for the latter.
Could the fact that certain scientists have recently begun to regard themselves as theologians also be called a paradigm shift?
I think so, in so far as a paradign is defined as a theoretical framework for the examination of phenomena. I think it was T. S. Kung who first popularised the term in this sense. I have no objection to scientists as such moving into the theological realm providing that they understand the paradign they are using. But most of them, as Frank suggests, simply don’t. This is a pity because a broad grasp of different paradigms can throw light by comparison and contrast.
I should perhaps have commented on Tim’s views about professional relationships. But I had to find time to look at the late Professor Stuart Sutherland’s accounts of this question in his book “Irrationality”. He confirms that experts routinely overestimate their expertise. He is particularly hard on doctors, who are biassed in their diagnoses towards their own specialities. They are also given to being influenced by incidents within their experience, and fail to look at the much better established general experience. Nor is this surprising because they do not always understand statistics and probability. Particularly Bayesian statistics. But they are not alone – the problem is common. I am not advocating self-medication however – only establishing through a bit of questioning whether they know their onions. And why not use Google for the purpose, after all many doctors do – and find it very useful.
When I was running a unit trust company I would meet regularly with a highly-feed group of investment experts. They talked impressively, but they might just as well have used a pin when picking stocks. I could go on to look at lawyers, but charity forbids me. All these groups follow the same Pareto rule: one competent to nine incompetent. I just like to know which I have got.
I don’t think I was being overly cynical, as RM Blaber suggests: unless assuming human weakness in experts is cynical.
As to climate change, I’m fed up hearing how bad it will be for Africa, as one example: I know for a fact that, during the Holocene Altithermal (7,000 to 5,000 years before present), the Sahara was covered in grass; southern Africa had vast tracts of seasonal forest, which only opened out to grassland and savannah around 1500 BC. Temperatures then were 4-5°C warmer than at present, and even now a warm year in South Africa is a wet one. The reason? The sun was unusually constant and luminous at the time.
An interesting article is at: http://www.telegraph.co.uk/news/uknews/1533290/Climate-chaos-Don%27t-believe-it.html
The problem with the climate change debate is that it takes place in the media – and journalists are militantly ignorant.
I don’t disagree with any of Quentin’s specific points. I suspect that we are all strongly influenced by our prrsonal experiences, more than can be justified objectively. My point is that it is important to trust your expert if you are to get the best from the relationship: Quentin’s, that you need an expert who is worthy of your trust, doesn’t contradict this. However, as one who regards himself as a lawyer, I’d like to hear more about his problems with lawyers: otherwise I’m left with the fear that he may be indulging prejudice. There is a point to lawyers, if only to ask questions:”Indeed, Rabbi, but what exactly are we to understand by the term ‘neighbour’ in this context?”.