On Doing Science, Pulling Rugs and Surviving Revolutions
Today I learned that I've been brushing my teeth wrong the whole 34 years of my life. I was fully asleep and dreaming of watching a sushi chef lay some juicy, fresh-out-of-the-water molluscs on rice, when my partner's alarm clock went off and somehow, the first thing he needed to tell me, was this: "I checked the internet and I was right: you're not supposed to brush your teeth after eating, because the small food particles dragged by the brush will scratch your enamel".
I pulled my duvet over my face. I was still mostly asleep and butt-hurt that I didn't get to even taste the sushi, so my first reaction was to think no way this is right, isn't removing the bits of food, like, the whole point of brushing your teeth? The internet is wrong, obviously. Also, good morning, honey. You've been ruminating this all night, haven't you?1
Then, as we lay in bed drinking our coffees, my mind got over missing out on the sushi and started processing the new information properly. Because I'm a scientist by training, you see. In fact, both me and my partner are. And do you know what's the most important thing in science? The only one without which we can't even talk about science, even if it's technically not mentioned in the scientific method's most common formulations? It's not the experiments, not the measurements, not the equations full of weird symbols. Those are important too, but there are fringe cases that circumvent them. No, the most important thing in science, the pillar without with it all tumbles down, is the requirement to change your mind in the face of new evidence.
To understand this we must actually examine the definition of a scientific hypothesis. According to Wikipedia, a scientific hypothesis "is a proposed explanation for a phenomenon [that] must be based on observations and make a testable and reproducible prediction about reality". According to Karl Popper, one of the most influential philosophers of science, that "testable" is really key: not just the prediction, but the hypothesis itself must be falsifiable in order to be considered valid. What does that mean? Simply put, it means that it must be possible, at least in principle, to prove that the hypothesis is wrong. To make and interesting example, this is a potential problem for the existence of dark matter: if dark matter doesn't interact with the rest of the universe in any visible way except for gravity, then we can't really prove it doesn't exist, do we? You can always say that the reason you didn't find it is not because it's not there, but because it isn't detectable. And that's why some cosmologists are critical of the dark matter hypothesis and would rather tinker with the theory of gravitation, even if that opens a whole other can of cosmic worms.
So, what does that have to do with brushing teeth? Well, it has to do because it touches on what is maybe my biggest peeve about the public perception of science, that which holds that science is immovable and monolithic and rejects new or different experiences on a principle. It doesn't, to the point where being able to be proven false is a requirement for every theory and hypothesis, it's just that in the real world things are more complicated than this.
There's a notion among people, and especially "alternative" people and fans of the new age and the paranormal, that the reason why their quack theories are not taken seriously by the scientific establishment is because they go against the "dogma" of the "official" science. That's not only false, but it damages the credibility of science in the eyes of a society that really depends on it, as we have seen recently with things like COVID and climate change. I also don't want to say that there's never merit to the accusation: I know that historically (and sometimes still now) the voices of many people have been ignored, the knowledge of non-European societies discarded. I've seen first-hand how some small fields of research can become echo-chambers, because there's only a few veterans in them and the many young post-doctoral fellows with short-term contracts don't dare go against them. And of course, it must really feel like the rug is being pulled from under your feet when your whole body of work is proven wrong and you have to start your research from square one. Those are real problems that merit their own pawst, but there's a difference between rejecting a hypothesis because of bias and rejecting it because it was proven false, which is what happened to most alternative medicines and paranormal claims. If experiments or observations prove your hypothesis wrong, you have to let it go. You don't get to claim discrimination, and you're actually trivializing real discrimination and making it look less credible if you do.
Remember that time astrophysicists decided Pluto was not a planet after all? Well, that was a really good example of science changing their view in light of new data, but people took it as if it affected them personally. People who I'm sure had never thought of Pluto after elementary school were suddenly writing opinion columns on how ludicrous this was. In fact, in one of the editorials I remember well, the writer was whining that he had learned in school that Pluto was a planet and now, at 50, he was asked to rethink it? The scandal! He was having exactly the reaction scientists are accused of when the new UFO sighting occurs, but because he was writing against science, it apparently didn't have the same implications. "Alternative" people are never accused of bias when they refuse to let go of their pet theory, just because they don't like the proven explanation.
There's a quote that I love that goes: "To doubt everything, or, to believe everything, are two equally convenient solutions; both dispense with the necessity of reflection"2. I think it applies to our topic too: accepting everything as fact and rejecting everything on principle will both relieve us from the effort of thinking. They are the easy road, but there's never anything good to see on the easy road. Be the one who is willing to take the hard one. Change your mind.
I, for myself, will try to brush my teeth before breakfast.
