A Quick Note on the Word “Theory”

Before we get into the next topic, the word “theory” deserves some context. To us in science, the word theory does not mean what it does to most other people.

You may say something like, “it’s my theory that if I skip lunch, I’ll be hungry.” While that’s not entirely incorrect, it is not quite the same as how we use the term in science. Your lunch theory is an educated guess, based on how you’ve felt in the past when skipping lunch. We usually tend to call that a hypothesis – an educated guess based on past observations.

A theory, on the other hand, is something we have tested exhaustively and has proven true again and again. In fact, it is so good; we tend to use it to do other science, assuming it is true.

Think of Einstein’s Theory of Relativity. Relativity is not a guess. We use it to send astronauts to the ISS. It is used to make sure your smartphone works. It is used all day, every day. So, bear that in mind when we introduce theories. These are, to the best of our knowledge, true and provable.

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