Abstract

Some scientific ideas make a transition from speculation, to hypothesis, to well-supported-theory, to fact. Clearly this happened for the basic Copernican claim that the Earth turns on its axis and orbits the Sun. There are many other examples, and nearly all so-called ‘anti-realists’ will accept many of the examples just as much as so-called ‘realists’; very few philosophers doubt that smoking causes cancer, or that contemporary global warming is anthropogenic.

But to-date there is scant scholarship on the topic of when we should say that a scientific claim has become an established scientific fact. The renowned evolutionary biologist Ernst Mayr ‘often deplored that he was not aware that philosophers of science have investigated this transition from theory to fact’ (Hoyningen-Huene, 2022). Recently, IPCC report writers have sometimes struggled with the same issue; one such writer recently asked, ‘Where is the boundary between “established fact” and “very high confidence”?’ (Janzwood 2020). For both scientific and political reasons, IPCC authors really need to know where this boundary lies. Or, if there is no boundary as such, they need at least sufficient conditions for when something can be called a ‘fact’.

In Identifying Future-Proof Science (2022), I tackle this question head-on. Building on Oreskes, Why Trust Science? (2019), I argue that one determines an established fact not by looking at the science, but, rather, by looking at certain features of the scientific community (second-order, not first-order, evidence). I argue that a fact can be identified when there is a 95% consensus within a scientific community that is large, international, and diverse, and where that consensus has been reached through bona fide scientific activity (thus ruling out tacit background assumptions).

In the entire history of science, whenever these criteria have been met the claim in question has never been overturned, despite enormous opportunity for that to happen, if it were ever going to happen. Thus a scientific claim meeting these criteria can be called a future-proof scientific fact.