On Reliability and Falsifiability

The American scientist C. S. Peirce, known as the “father of pragmatism”, coined the term fallibilism, which is the position that we can never be completely certain about factual issues. The Austrian-British philosopher Karl Popper placed great emphasis on this idea, extending it to say that we can never be completely sure a theory is true.

To a certain extent, this makes a great deal of sense. Throughout history, time and time again we have seen scientific theories and ideas previously considered to be well-supported turn out to be false⏤a perfect example being Newtonian physics, shown to be false in several respects in the 20th century after spending hundreds of years as one of the best-supported theories of all time. How can we ever truly rely on what we know, if what we know could change at any given moment?

Popper⏤whose primary aim was to understand science, believing science to be a search for true descriptions of the world⏤states that all we can do is try out one theory after another, and if a prediction comes out as predicted, then all we can say is that we have not yet falsified the theory. We keep testing until we succeed in falsifying it, and we never increase our confidence in the truth of the theory.

This seems grim, almost nihilistic⏤but it is important to keep in mind that this is one way we can remain driven to uncover deeper truths. The two-step, endless cycle of scientific change⏤conjecture and subsequent attempt at refutation⏤encourages scientists to constantly strive to develop predictions with increasing precision. Hypotheses should be risky, according to Popper, and we should never stop trying to falsify them, always retaining a tentative attitude toward them no matter how successful they have been in the past.

It seems the best way to approach science is with a healthy, rather than nihilistic, inductive skepticism, wherein the more tests a theory passes, the more confidence we can have in its truth; but we should never become too married to our hypotheses, and we should reject them when testing tells us we need to.

Silly as the movie may seem, I’ve always found this quote from Men in Black to be surprisingly salient, summing things up quite well: “Fifteen hundred years ago everybody knew the Earth was the center of the universe. Five hundred years ago, everybody knew the Earth was flat, and fifteen minutes ago, you knew that humans were alone on this planet. Imagine what you’ll know tomorrow.”