Appraising and Amending Theories: The Strategy of Lakatosian Defense and Two Principles That Warrant It

In social science, everything is somewhat correlated with everything (“crud factor”), so whether H0 is refuted depends solely on statistical power. In psychology, the directional counternull of interest, H*, is not equivalent to the substantive theory T, there being many plausible alternative explanations of a mere directional trend (weak use of significance tests). Testing against a predicted point value (the strong use of significant tests) can discorroborate T by refuting H*. If used thus to abandon T forthwith, it is too strong, not allowing for theoretical verisimilitude as distinguished from truth. Defense and amendment of an apparently falsified T are appropriate strategies only when T has accumulated a good track record (“money in the bank”) by making successful or near-miss predictions of low prior probability (Salmon’s “damn strange coincidences”). Two rough indexes are proposed for numerifying the track record, by considering jointly how intolerant (risky) and how close (accurate) are its predictions.