We must not “believe” in science, but trust the scientific method

Sometimes, I think it’s necessary to start over from the basics. This is what happens to me when, having explained the meaning of yet another scientific article that brings to light interesting results on some socially controversial topic – vaccines, GMOs or something else – someone invariably takes refuge behind a typical comment. “Science is doubtful” – it is said – and “one cannot believe in science”. It’s true: science cannot and must not be believed, but simply because it makes no more sense to talk about belief in science than it does to believe in arithmetic. That verb, speaking of science, simply doesn’t apply.

There is therefore a profound misunderstanding, due to the fact that we would like to take the result of a scientific investigation and establish its truth content, treating it as if it represented any statement about the physical world, and not a proposition endowed with a probabilistic estimate and connected to certain assumptions and certain measures that delimit its field of application in a precise way (also due to the way in which certain scientists communicate their results). The result of a scientific investigation is confused with the method that led to that result; and in a method, which is by extension the entire scientific procedure, errors can be discovered at most, but it cannot be the object of belief.

So no, one cannot believe in science, just as one cannot inhabit chemistry: the verb simply does not apply to the object.
The interesting thing, however, is that, while having to give up believing, we can trust a method, the scientific one, for the way it proceedsas I will try to illustrate briefly.

All living beings – even the simplest of bacteria – acquire information from the physical world, in the sense that, using particular ways of sensing the environment, they are able to identify favorable or adverse conditions, and to direct their behavior accordingly. . This ability can be innate, when evolution has forged through selection the ability to distinguish between environmental states that are significant for one’s survival and proliferation, or learned and culturally transmitted, for organisms equipped with systems suited to the purpose; in any case, however, the point is that the ability to discover the association between certain clues and the occurrence of certain environmental conditions is among the most advantageous traits for any form of life. Furthermore, since for the most part it is not established a priori which clue is useful for revealing a given environmental condition to an organism, exploratory behavior is also a favorable trait, if understood as the search for new relationships, through the mechanism of associative reinforcement between the appearance of a clue and the occurrence of a certain circumstance.

To discover these relationships, it may take a long time, and it may not be enough; or, one can voluntarily reproduce a given event a sufficient number of times, identifying the relationships that link together certain observable quantities and the final result. Suppose, for example, I am suspicious that a die is loaded; I could begin to observe which number comes up every time it rolls randomly pushed by a strong wind or a powerful seismic shock, or I could roll the die a sufficient number of times, until I verify if indeed some numbers come up with a different frequency from the others . This is, in essence, the experimental method; as can be seen, to test my hypothesis I had to reproduce the event in question, in a controlled way, and I had to count, i.e. I had to mathematise my observations. If the die is not loaded, I will observe that all the numbers roll out at a frequency that is gradually more similar, only as the number of rolls increases; it will hardly happen that, after only 6 tosses, I will see each number roll once, but after 1000 tosses, it will be more or less like this. How much and what I will observe, how often: this is the field of statistics, which, as we can see, also finds application in the analysis of almost trivial hypotheses about the physical world – whether or not a dice is loaded.

Now, the problem is that I am almost never in a position to carry out an experimental verification of a given hypothesis, or to derive a mathematical verification from it; much more often, I am faced with a series of scientists, each of whom affirms something about the degree of truth of that hypothesis, even in contrasting ways with each other. Again, I don’t need to believe anyone. Suppose I don’t have access to the die I suspect in the example above: I could ask players who have identical dice to it (the scientists with their experimental setups) to report back their results. It could be that, after ten rolls, a player has observed only the number 4 roll, and he tells me that the die is loaded; but if I ask many scientists, each able to conduct an experiment independently by rolling the die a certain number of times, I will be able to verify whether, given many independent players and many rolls of the dice, in the end the numbers come out in the same sequence or not. This is the verification of scientific consensus, which each of us can qualitatively carry out by looking for how many scientists independently support a given thesis, or which can instead be quantitatively carried out through particular studies such as meta-analyses, capable of deducing agreement on a certain problem of interest, investigated by several different scientists.

The scientist-player who has only obtained 4 will continue to scream that the dice are loaded, but after the check his thesis will be falsified; I must instead avoid the behavior of someone who, suspicious of dice from the beginning, chooses that scientist, ignoring the others, and presents his analysis as proof of his suspicion. Of course, it could be that all the dice are loaded in the same way – that is, that all scientists are subject to some bias, mental or experimental, which distorts their analysis – and therefore that single independent genius who wants to put us on the line could be right. ‘notice; but, since this is obviously an unlikely hypothesis, to be convinced we would first have to find what is wrong with the other people’s measurements.

There is no belief in the process illustrated; there is only updating what is known about the world, based on an incremental method, which is limited only by the human ability to follow it.

No, I don’t believe in science; I apply a method, the same one at the basis of the molecular computations that make us live, and I draw more or less firm consequences from it.