Verifiabiliteetti

Verifiabiliteetti, or verifiability, is the quality of a statement or theory that makes it possible to confirm or disconfirm it through observation, experiment, or logical reasoning. In empirical inquiry, verifiability is linked to the idea that evidence obtainable by experience can support or refute claims.

Historically, verifiability was central to logical positivism and the verificationist principle, which held that the meaning of a sentence lies in its method of verification. This view shaped much of early 20th‑century philosophy, particularly among the Vienna Circle and philosophers such as A. J. Ayer. The emphasis was on observable procedures that could demonstrate truth or falsehood.

The stance faced substantial critique. Karl Popper argued that science progresses through falsification rather than verification, contending that theories should be testable in ways that could show them false. He saw verifiability as insufficient for demarcating science from non‑science. Later discussions introduced notions of confirmation, probabilistic reasoning, and Bayesian approaches, which treat evidence as a matter of degree rather than binary verification.

In practice, verifiability influences how researchers assess hypotheses: they seek observable consequences, reproducible results, and measurements that can be independently checked. In addition, verifiability extends beyond science to fields such as technology, law, and information security, where claims or identities must be verifiable. Limitations include that not all meaningful claims are readily verifiable in a single experiment, and accumulated evidence often governs acceptance rather than direct verification alone.

Today verifiability remains a historical and methodological reference point in philosophy of science and evidence-based practice, while emphasis often shifts to testability, falsifiability, and the strength of cumulative empirical support.