A claim is falsifiable if you can describe an observation that would show it to be wrong. 'This drug lowers blood pressure within a month' is falsifiable: measure blood pressure and it may not drop. 'Everything happens for a reason' is not: any event whatsoever can be read as fitting. Unfalsifiable claims feel strong because nothing ever contradicts them, but that is exactly the problem. A claim that forbids nothing tells you nothing about what to expect, so it cannot be tested and cannot earn support. Watch for claims that become unfalsifiable on contact with evidence: a psychic's failure is blamed on the sceptic's negative energy, a failed prediction is reinterpreted, a theory absorbs both an outcome and its opposite. Asking 'what would change your mind?' is the practical test. If the honest answer is 'nothing', the claim is a belief to hold, not a finding to trust. Falsifiable does not mean false; it means testable. After this Concept you can decide whether a claim is falsifiable, name the observation that would refute it, and spot the rescue moves that make a claim immune to evidence.
Falsifiability is the test of whether a theory could be proven wrong, used to judge if a scientific claim is worth believing. Karl Popper proposed that a good scientific theory is falsifiable in prin…