Probandum

Probandum is a Latin term meaning “that which is to be proved.” In the philosophy of science, it is used to denote the problem or proposition that a theory aims to solve or explain—the empirical content that would count as evidence for or against the theory. The probandum specifies the testable claims a theory makes and thus what would count as refutation if contradicted by observation.

In Karl Popper’s account of scientific method, the probandum plays a central role in falsificationism. Scientists propose bold conjectures, and the probandum describes the specific empirical consequences that would, if observed, falsify the conjecture. Importantly, the probandum is not a guaranteed truth but a testable commitment; a theory with a well-defined probandum can be subjected to critical testing, and a single counterexample can undermine it.

A well-formulated probandum yields clear predictions. When observations align with these predictions, the probandum is corroborated and the theory gains credibility, though it is not proven beyond dispute. When observations conflict with the probandum, the theory faces potential rejection or revision.

Example scenarios often cited involve gravitational theory or other physical laws, where the probandum encapsulates the expected empirical relationships (such as specific force laws and orbital behaviors). The strength of a theory, in Popper’s view, rests on the falsifiability of its probandum rather than on confirmatory evidence alone.

See also: falsifiability, hypothesis, conjecture, Karl Popper.