We are now 55 years removed from the publication of Karl Popper’s Logic of Scientific Discovery (1959), in which Popper argued that falsification is an essential character of science, and it seems that very few of us in society actually embrace this notion to understand how and why they should be skeptical of ‘studies that show…’.
Popper’s argument goes something like this. Before the age of discovery, when explorers from Europe journeyed to the four corners of the globe, Europeans held the belief that all swans were white. This seemed to be a natural conclusion. After all, every swan that had been observed and reported had been white, and it was reasonable to assume that every swan that was, is, or will ever be, is white. On January 10, 1697, the Dutch explorer Willem de Vlamingh found a habitat sporting a large number of black swans in and around the Swan River on the west coast of Australia. His observation put an end to any validity of the claim that ‘all swans are white’.
In Popper’s logical structure, de Vlamingh’s observations falsified the hypothesis that an essential property of swans is their color. Using this example as a prototype, Popper then generalizes a guiding principle that no scientific theory can be proven, it can only be falsified.
Now, I expect that most educated people in society would reply, if asked, that they are aware that a scientific theory can never be proven, only disproved, and that they accept this as an essential facet of the scientific enterprise. Some of the more knowledgeable may even point out the radical modifications required to Newtonian physics caused by the observations that eventually led to the birth of Quantum Mechanics and General Relativity.
And yet, these very same people seem to blindly believe any ‘fact’ that comes to light, as long as its sales pitch starts with ‘scientist have discovered’. The media continually bombards us with stories of this kind, telling us about how a new study shows that eating this or that raises or lowers the risk of us contracting some horrible malady. That kids who play video games or watch too much TV (however ‘too much’ is defined) are being driven to greater levels of violence or obesity or whatever. Regardless of the subject matter, a vast component of our society is gullible and quite ready to believe as proven cause-and-effect any set of statistical correlations that a scientist may happen to discover in a set of data.
Before I am accused of being unfair and overly critical, I do want to state that I recognize that real life is never as simple as the idealized situation portrayed in the black swan anecdote. For example, imagine ourselves as contemporaries of de Vlamingh who stay at home in Holland. After he arrives home, we happen to be at a meeting where he is presenting his black swan observations. Why should we just give up on the ‘all swans are white’ hypothesis solely on his say so? Perhaps the birds he observed are not actually swans but birds that look similar. Perhaps they were actually white, and a recent fire had covered them with soot. But suppose he came back with the body of a black swan and all our tests and examinations indicate that the bird is indeed black and a swan. Does this mean that we have, with certainty, disproved the white swan hypothesis? I think the answer is a qualified yes. That is to say, we can no longer cling to the notion that all swans are white even if we later narrow the definition of ‘swan’ so that the hypothesis again becomes acceptable.
On the surface, it may seem that the preceding argument invalidates Popper’s approach, and that this whole enterprise is self-contradictory. But some careful thought and identification of what is essential versus what is accidental in the scientific method assures us that we are on firm ground.
The essential aspects of the scientific enterprise is that we can believe that the world is understandable and that logic and the scientific method work as tools to reach this understanding. These beliefs are meta-physical in that they rise above the accidents of any particular scientific hypothesis, theory, or test, and they are not ‘provable’ or ‘disprovable’. We simply identify them as essential aspects of the world and how we interact with it. The accidental aspects are all that remains.
To try to illustrate this, let’s return for the final time to these annoying black swans and to de Vlamingh, who caused so much trouble. The essential aspect in this historical narrative is that Europe held the belief in white swans based on a very large number of observations. To hold a belief about the world is to tacitly assume that the world is understandable and that reason is a tool to understand it. The accidentals of the narrative are that 1) prior to de Vlamingh’s observations all swans were white and 2) after his observations that belief could no longer be held unchallenged or unmodified. The fact that we can argue whether the de Vlamingh’s birds are really swans or really black or whatever is only a discussion about the accidentals of the bird and not the essentials of understanding the world.
So what I am criticizing in society is not that people can be confused about how to draw conclusions from scientific data, nor am I criticizing them for drawing conclusions I would not. What I am criticizing is the acceptance of scientific conclusions without skepticism. I am criticizing misplaced faith, which focuses on the accidental observations of a given study, and loses sight of the essential unprovable nature of the scientific method. I worry about a society that uncritically accepts the term ‘Settled Science’ and turns its back on Black Swan Science.