── ── Mental model

Falsifiability

A meaningful empirical claim must specify what observations would refute it. Claims that resist all possible refutation are not science — they are unfalsifiable belief. Formalized by Karl Popper (1934): science progresses not by accumulating confirmations but by surviving rigorous attempts at falsification. More-specific claims are more falsifiable; ad-hoc modifications that explain away failures destroy a claim's scientific status.

How it works

Step 1 — State the claim: claim / who asserts it / decision dependent on it / current evidential basis.

Step 2 — Test whether empirical: claim about how the world works (empirical) or values/aesthetics (non-empirical)? If non-empirical, stop here.

Step 3 — Specify falsification conditions: complete "This claim would be falsified if I observed: ___" — specific, observable, time-bounded. If you cannot complete it, the claim is not falsifiable as stated.

When to use it

• user says 'what would prove this wrong', 'how do we know if our strategy is working', 'what would change your mind', 'this claim feels unfalsifiable', or is designing a hypothesis/experiment/investment thesis that needs to be made testable

Worked example

Popper 1934 + Eddington 1919 Eclipse + Modern Applications

Karl Popper (1902-1994) was an Austrian-British philosopher whose 1934 Logik der Forschung (translated as The Logic of Scientific Discovery in 1959) reshaped 20th-century philosophy of science. Popper had observed the rise of psychoanalysis (Freud, Adler) and Marxism in Vienna during the 1920s, and was struck by how their adherents claimed they "explained" everything — every observed event could be interpreted as confirming the theory. Popper's diagnosis: any theory that explains everything explains nothing. Such theories make no risky predictions; they cannot fail; therefore they are…