A friend pointed me to this existential comic (click through for the full thing)
There are several layers to the humour in the Fallacy Man strip, which is always good to see. As is usual with humour, there is a larger point to be made here. For me, the point to be made is about how science is done.
Proof is hard to come by, in science. We all know the great asymmetry between evidence for and against a scientific theory: you can gather all the evidence in the world in support of your favourite theory, but one observation that doesn’t fit with your theory renders it false. This is the Popperian view of science as falsifiability.
But science research in practice hardly ever works like this. I mean this at two levels. The first is more obvious and less cynical than the other: most people who find outlier data in the lab assume not that the theory they are testing is false but that they’ve made an error somewhere. This is true of first year undergrads who ‘discover’ with their simple pendulum that the local value of g is 8ms-2; nobody concludes that Newton’s theory must be wrong1. It is also true of sophisticated experiments that show neutrinos travelling faster than light. The first thought physicists had wasn’t ‘Einstein was wrong’, but ‘there must be something wrong with the experiment’2.
The second, more problematic, sense in which Science doesn’t work in the Popperian falsifiability way has to do, as I see it, with the role of authority. Science today is, for better or worse, so vast and varied an enterprise that it’s impossible for one person to know more than a sliver of all knowledge 3. This is uncontroversial. This means that for anything that doesn’t fall within the sliver in which a scientist could claim expertise, he has to rely on other people.
What happens when the experts are wrong?
That question isn’t hypothetical. Experts (or people who fashion themselves experts) are routinely wrong. Sometimes because they overestimate what they know (think Linus Pauling and Vitamin C); sometimes because the questions they are trying to answer have no good answers (just on the subject of human health: is coffee good for you? is red wine? how about running?)
This is to say nothing of when experts are ‘deliberately’ wrong. Is fat good for you or bad? For 50 years, we’ve thought fat-free (which means artificially loaded with sugar) was the way to good health because researchers at Harvard were paid off by the sugar industry.
Science advances one funeral at a time, said Max Planck. That’s an observation that’s deeply, fundamentally, at odds with the idea that science is the search for evidence contrary to the hypothesis being tested. Can the objectivity of the scientists be separated from the objectivity of science itself?
I don’t want to go overboard with the postmodernist idea that science is no more objective than any other way of knowledge. But, except in physics or chemistry, where the presence and influence of the human element can be controlled for, or even eliminated, it seems to me a warning worth paying heed to4..
1. What might the student have done to get this value for g? Assuming g is 9.8 ms-2, this value of g would mean the student was enthusiastic about the pendulum’s amplitude of oscillation. See here.
2. The error was, needless to say, in the experiment, and not the correctness of Einstein’s relativity. There was a fibre-optic cable that wasn’t attached correctly.
3. “Philosophers are people who know less and less about more and more, until they know nothing about everything. Scientists are people who know more and more about less and less, until they know everything about nothing.” – Konrad Lorenz
4. Does this make physics or chemistry “purer” sciences than biology or psychology or (gosh!) economics? That’s akin to arguing that studying spherical cows (with ellipsoidal perturbations?) is the only pure way of doing science.