How to Identify a Scientific Fact

Peter Vickers

When do we have a scientific fact? Scientists, policymakers, and laypersons could all use an answer to this question. But despite its obvious importance, humanity lacks a good answer. The renowned biologist Ernst Mayr was one scientist—probably one of many—frustrated by the fact that philosophers of science haven’t developed an account of the transition from theory to fact*. And recently an IPCC Special Report author explicitly asked, “Where is the boundary between ‘established fact’ and ‘very high confidence’?”. The truth is, nobody really knows.

And it matters. We want governments to base policies on scientific facts, insofar as that is possible. And the IPCC Report writer needs to know whether they are allowed to simply state something, or if they need to include a clause in brackets at the end of their statement: “(very high confidence)”. Moreover, in a world where we have no account of “scientific facts,” it is no wonder we encounter so much scepticism regarding even the most secure scientific claims.