1. The Vocabulary of Science


What I mean by the vocabulary of science is terminology like “theory”, “hypothesis”, “law”, “fact”, “model”, and so on. What do these terms mean? How are they used by scientists and non-scientists? What insight can they give us into the nature of science and scientific reasoning?

These questions are important because a number of debates about science, or about the status of certain theories, are framed in ways that exploit assumptions about what terms like “theory” and “fact” mean, or ought to mean.

So for example, in debates over the status of evolutionary theory, you’ll hear critics say things like “evolution is a theory, not a fact”, and then you’ll hear evolutionary proponents counter with “No, evolution is fact, not a theory”, or “No, evolution is both a fact and a theory”, and readers who aren’t familiar with how these terms are used might be understandably confused about what’s being said and what people are actually disagreeing about.

In fact there’s a small cottage industry devoted to articles and blog posts and YouTube videos that focus on precisely these questions, for these very reasons. The people who write these articles want to intervene in these debates about the scientific status of some subject by legislating on the “proper” way to interpret scientific vocabulary, usually because they think the people on the wrong side of the issue are either confused about what these terms actually mean, or are willfully misusing them for rhetorical purposes.

I’ve looked at an awful lot of this vocabulary policing, and I can tell you that most of it is messed up. It’s well meaning, but it’s messed up.

These vocabulary policing articles routinely say things that no philosopher or historian of science would say, they are routinely too narrow or too broad in their definitions, and they are routinely inconsistent in their usage, defining a term one way and then using the term in a way that contradicts the definition they just gave.

The root of the problem, I think, is the assumption, that all these efforts seem to share, that scientists use these terms with very specific meanings that are unfamiliar to the public, so they divide meanings into proper scientific usage and popular usage, and then they assume that, for any given scientific term, there is only one legitimate scientific usage, and they’re going to tell us what that usage is.

The problem is that both of these assumptions are demonstrably false, and this generates a lot of problems with how the issue is discussed from this point forward.

So, I agree that a thoughtful analysis of the vocabulary of science is a great tool for promoting science literacy, because it focuses attention on core concepts in scientific reasoning that apply across the sciences.

But this discussion needs to be informed by what philosophers and historians of science have been writing on these topics for decades, and in some cases, centuries.

And that’s what I propose to do in this first unit, where we’ll talk about the various ways that of each of these terms are used — theory, fact, law, hypothesis, and model — both within science and outside of science.