“A system is part of empirical science only if it can be refuted by experience.”Karl Popper · Logica cercetării · 1934 · Logica cercetării, Cap. I, § 6
A theory is scientific only if there is some possible result that could prove it wrong.
Popper proposes a demarcation criterion between science and pseudoscience: a theory is scientific if there is a test that could refute it. Theories that cannot be wrong, such as astrology or classical psychoanalysis, are not scientific. For example, the statement 'all swans are white' can be refuted by a black swan, whereas 'the universe has a purpose' cannot be tested.
Falsifiability does not mean a theory is wrong, but that it can be tested. When a friend says a new diet works for everyone, this cannot be disproved by a counterexample. A truly scientific theory would say: this diet works for 80% of people, and the rest are exceptions. This way you can check for yourself if it works. The next step is to understand how to apply this test to your daily choices.
Why it matters Today, this principle helps us distinguish real science from conspiracy theories or unvalidated remedies, encouraging critical thinking.