AdhocHypothesen

AdhocHypothesen, or ad hoc hypotheses, are auxiliary assumptions introduced to a theory primarily to save it from being contradicted by new data. They are typically added after an anomaly arises in order to maintain the viability of an existing framework rather than to generate independent, testable predictions.

Key characteristics include a lack of independent justification and limited predictive power beyond addressing the specific anomaly. Ad hoc hypotheses are often viewed skeptically because they can shield a theory from falsification without improving its overall explanatory or investigative value. In scientific practice, they are most defensible when they lead to new, testable predictions or when they are clearly distinguished from the core principles of the theory.

Philosophical context emphasizes the tension around ad hoc modifications. Karl Popper argued that excessive ad hocism undermines falsifiability, a cornerstone of scientific testing. The Duhem–Quine thesis notes that data cannot fix a single hypothesis in isolation because auxiliary assumptions can be adjusted as well. Some frameworks, such as Lakatos’s notion of research programs, allow a protective belt of auxiliary hypotheses around a hard core, but warn against unprincipled, ad hoc shifts.

Historical examples often cited include the use of epicycles in geocentric astronomy to account for planetary motion, and the 19th-century aether hypothesis to explain light propagation. Both illustrate how ad hoc adjustments can temporarily preserve theories but may hinder progress if not tested or revised in light of new evidence.

Today, ad hoc hypotheses are not categorically prohibited; they are scrutinized for their testability, explanatory scope, and ability to yield independent predictions. Clear articulation of auxiliary assumptions and ongoing empirical evaluation are considered best practices to avoid unproductive ad hocism.