(…)
Now what are we to think of a scientist who seems competent inside the laboratory, but who, outside the laboratory, believes in a spirit world? We ask why, and the scientist says something along the lines of: “Well, no one really knows, and I admit that I don’t have any evidence - it’s a religious belief, it can’t be disproven one way or another by observation.” I cannot but conclude that this person literally doesn’t know why you have to look at things. They may have been taught a certain ritual of experimentation, but they don’t understand the reason for it - that to map a territory, you have to look at it - that to gain information about the environment, you have to undergo a causal process whereby you interact with the environment and end up correlated to it. This applies just as much to a double-blind experimental design that gathers information about the efficacy of a new medical device, as it does to your eyes gathering information about your shoelaces.
Maybe our spiritual scientist says: “But it’s not a matter for experiment. The spirits spoke to me in my heart.” Well, if we really suppose that spirits are speaking in any fashion whatsoever, that is a causal interaction and it counts as an observation. Probability theory still applies. If you propose that some personal experience of “spirit voices” is evidence for actual spirits, you must propose that there is a favorable likelihood ratio for spirits causing “spirit voices”, as compared to other explanations for “spirit voices”, which is sufficient to overcome the prior improbability of a complex belief with many parts. Failing to realize that “the spirits spoke to me in my heart” is an instance of “causal interaction”, is analogous to a physics student not realizing that a “medium with an index” means a material such as water.
(…)
In modern society there is a prevalent notion that spiritual matters can’t be settled by logic or observation, and therefore you can have whatever religious beliefs you like. If a scientist falls for this, and decides to live their extralaboratorial life accordingly, then this, to me, says that they only understand the experimental principle as a social convention. They know when they are expected to do experiments and test the results for statistical significance. But put them in a context where it is socially conventional to make up wacky beliefs without looking, and they just as happily do that instead.
(…)
Reality, we have learned to our shock, is not a collection of separate magisteria, but a single unified process governed by mathematically simple low-level rules. Different buildings on a university campus do not belong to different universes, though it may sometimes seem that way. The universe is not divided into mind and matter, or life and nonlife; the atoms in our heads interact seamlessly with the atoms of the surrounding air. Nor is Bayes’s Theorem different from one place to another.
If, outside of their specialist field, some particular scientist is just as susceptible as anyone else to wacky ideas, then they probably never did understand why the scientific rules work. Maybe they can parrot back a bit of Popperian falsificationism; but they don’t understand on a deep level, the algebraic level of probability theory, the causal level of cognition-as-machinery. They’ve been trained to behave a certain way in the laboratory, but they don’t like to be constrained by evidence; when they go home, they take off the lab coat and relax with some comfortable nonsense. And yes, that does make me wonder if I can trust that scientist’s opinions even in their own field - especially when it comes to any controversial issue, any open question, anything that isn’t already nailed down by massive evidence and social convention.
(…)
It’s not a different universe inside and outside the laboratory.
(Source: lesswrong.com)