Professional scientists mostly ignore the slogans (e.g., “absence of evidence isn’t evidence of absence”) I discussed in my previous post. For example, the professional-scientific conclusion that smoking causes lung cancer came mostly from correlations. This conclusion was criticized, sure, but not by saying “correlation does not equal causation”.
Professional scientists have a much worse problem, which is that they criticize much more easily and fluently than they praise. (Marginal Revolution is an excellent blog partly because it doesn’t suffer from this.) This can be depressing (lots of work is underappreciated), exciting (anyone who sees this has a big advantage), or merely amusing, as in this example to which Stephen Marsh drew my attention:
I just returned from the MS4 conference. It is the fourth year that a group of philosophers of science have gathered to try to tease apart the implications of computer simulation in science. . . .Several presentations gave harsh criticism of climate science models. Bayesian tools (a statistical technique) were given some especially harsh criticisms. Everyone agreed the models were problematic in some sense or another. That the results were subject to all kinds of errors and suspicions, and there were substantially difficult difficulties to sort out. . . . Despite this, everyone concurs the models are robust . . . No one disagreed that the planet was warming.
The poor ability of professional scientists to praise means that comparison of A and B (two theories, say, or two experiments) mainly consists of comparing how much A and B have been criticized. How much A and B would have been praised, had scientists been better at praise, is unknown. This is a very poor way to compare stuff. Inability to praise also means that there is too much criticism. In my experience, scientists have trouble separating serious criticisms from trivial ones. For example, that climate-change models haven’t been shown to predict correctly is a serious criticism not emphasized enough (e.g., at the MS4 conference).