Have you ever wondered what truly distinguishes genuine science from pseudoscience? It’s a question with significant practical and theoretical importance. While many might intuitively say science is about finding evidence that supports a theory, the philosopher Karl Popper offered a surprisingly different answer.
Born in Vienna in the early 20th century, an era when theories like Marx’s theory of history and the psychological theories of Sigmond Freud were widely considered scientific, Popper found himself disenchanted with these ideas. He was particularly inspired by Albert Einstein’s theory of relativity. Popper observed that Einstein’s theory was distinguished by its openness to criticism, leading him to propose that falsifiability, not confirmation, is the hallmark of science.
Popper argued that finding evidence that confirms a theory is “cheap.” Pseudosciences, like astrology or the theories of Freud, often find confirming evidence everywhere. Their proponents can easily explain away apparent counterevidence or even turn it into confirming evidence. For Popper, if a claim cannot, in principle, be shown to be false, it isn’t scientific.
Genuine science, according to Popper, doesn’t seek to confirm its hypotheses, but rather to falsify them. Scientists should make bold conjectures and then design severe tests aimed at proving them wrong. If a theory survives strenuous attempts to falsify it, it is said to be corroborated. However, Popper insisted that corroboration doesn’t mean the theory is likely true or that it will be successful in the future. He reached this conclusion partly by accepting Hume’s argument that there’s no rational justification for relying on induction (the idea that past experience predicts the future), and then arguing that science doesn’t actually need induction if its goal is falsification rather than confirmation.
Popper’s view is elegant and influential, especially among scientists. However, it faces significant criticisms. For one, the line between falsifiable and unfalsifiable statements isn’t always clear, and some scientific statements (like those involving probabilities or existence claims) seem hard to falsify conclusively. A major challenge is the problem of auxiliary hypotheses. A theory doesn’t make predictions on its own; it requires additional background assumptions (auxiliary hypotheses). If a prediction turns out false, logic only tells us that at least one statement in the complex web of theory and auxiliaries is wrong, not specifically the main hypothesis being tested. Critics also question whether scientists should reject theories simply because they conflict with observation, noting that successful theories often have broad explanatory power, which Popper seemed to downplay as a virtue. Furthermore, Popper’s view struggles to explain why it is rational, for practical purposes, to prefer a corroborated theory over an untested one.
Despite these challenges, Popper’s emphasis on testability, criticism, and the distinction between science and pseudoscience remains a crucial part of the conversation in the philosophy of science. His idea that science progresses by eliminating falsehoods, rather than accumulating certain truths, offers a provocative picture of the scientific enterprise.