Definition

Ad hoc hypothesis denotes a supplementary hypothesis given to a theory to prevent it from being refuted. According to Karl Popper’s philosophy of science, the only way that falsifiable intellectual systems like Marxism and Freudianism have been sustained is through the dependence on ad hoc hypotheses to fill gaps. Ad hoc hypotheses are used to account for abnormalities that the theory’s unaltered form could not foresee.

Explanation

Ad hoc theories are only acceptable if and only if their non-universal, precise nature can be shown, or, to put it another way, if their potential for direct generalization is disproven. It is the hypothesis that is embraced without any other justification in order to save a theory from refutations or criticism. This technique is deployed in sociological research studies.

The derivation of the particular conclusion in an issue may be deemed invalid if an ad hoc hypothesis was proven to be acceptable and non-universal; as a result, the specific example loses its scientific significance. The necessity of repeat testing is implied in the aforementioned working rule for the acceptance of ad hoc hypotheses, which makes this process seem all the more justifiable.

Notably, the system seems to be in question whenever the introduction of an ad hoc hypothesis is required until the acceptability of the ad hoc hypothesis appears to be established by the requisite falsification attempts. The restriction of ad hoc hypotheses and the continuity principle appear to guarantee the objectivity of falsification; in other words, a theory should only be regarded as falsified if its falsification is theoretically testable.

In addition, because it gives a preferential position to a critical evaluation or falsification, this principle of restriction serves as, in a sense, the second part of the working definition for the idea of a theoretical system’s falsification. Ad hoc hypotheses can be used to attempt to prevent falsification based on the continuity principle, but this can only be done if a different hypothesis, the generalized ad hoc hypothesis (which is also subject to the continuity principle), can also be refuted. Therefore, avoiding falsification depends on (yet another) deception. 

The first falsification will take effect if the second one is unsuccessful. This methodological constraint, or the concept of the restriction of ad hoc hypothesis, has effectively eliminated the “conventionalist argument to falsifiability.” The argument that this system is, in theory, not falsifiable has been demonstrated to be inconsistent (via the principle of the restriction of ad hoc hypotheses) provided that a system enables the derivation of empirically verifiable consequences in the first place.

Since the non-falsifiability of any hypothesis (even a generalized ad hoc hypothesis) would necessitate the falsifiability of other hypotheses, this principle gives a workable definition of the term “falsification” (that is, the falsification of the original axiomatic system). This is obviously inconsistent.

Example

The ad hoc hypothesis “This (otherwise accurate) watch showed the wrong time under such and such circumstances” is only a valid ad hoc hypothesis if the universal statement “All (otherwise accurate) watches show the wrong time under such and such circumstances” can be shown to be false, or refuted, by counterexamples.