Either Scientific American or I don’t understand the word “theory”

Scientific American has an article about 7 Misused Science Words. Number 2 is “theory”:

Part of the problem is that the word “theory” means something very different in lay language than it does in science: A scientific theory is an explanation of some aspect of the natural world that has been substantiated through repeated experiments or testing. But to the average Jane or Joe, a theory is just an idea that lives in someone’s head, rather than an explanation rooted in experiment and testing.

Although of course I applaud the broader point they’re making — saying something is “just a theory,” as, e.g., anti-evolution types do, isn’t an argument against its validity — this doesn’t sound right to me. A theory may have been experimentally substantiated, but it need not have been.

Is string theory (which is notoriously untested by experiment) not a theory? Was general relativity not a theory during the several decades during which it had minimal experimental support?

The article supports this definition with a link to a post at something called Livescience, which says (in its entirety)

A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. If enough evidence accumulates to support a hypothesis, it moves to the next step—known as a theory—in the scientific method and becomes accepted as a valid explanation of a phenomenon.

In my experience, this is not how scientists use the word. I know lots of physicists who come up with theories willy-nilly, and don’t feel the need to wait for experimental evidence before labeling them “theories.”

In the unlikely event that any creationists read this, let me reiterate: I am not saying that a theory necessarily lacks experimental support, so saying something is “just a theory” doesn’t constitute a logical argument against it. In particular, Darwinian evolution is a theory, which happens to be buttressed by phenomenal amounts of evidence.

Granted, this is pretty much just a quibble. I’m just easily irritated by cartoon descriptions of “the scientific method,” formed without paying much attention to what scientists actually do and then glibly repeated by scientists.

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Ted Bunn

I am chair of the physics department at the University of Richmond. In addition to teaching a variety of undergraduate physics courses, I work on a variety of research projects in cosmology, the study of the origin, structure, and evolution of the Universe. University of Richmond undergraduates are involved in all aspects of this research. If you want to know more about my research, ask me!

One thought on “Either Scientific American or I don’t understand the word “theory””

  1. I agree with you entirely.

    I often see similar attempts, in the name of explaining scientific method, to establish hierarchies, usually following some route from hypothesis to theory to law. I always find them arbitrary, naive, and confusing the main point.

    To those who complain that X is ‘just a theory,’ I recommend complete agreement: ‘you’re absolutely right, in exactly the same way that when you look up at a clear night sky, what you can see is just the universe.’

    In other words, ‘if you’ve got something superior to a theory, then bring it on.’

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