Theory vs. Hypothesis: What's the Difference?

A version of this commentary originally appeared in the June 29, 2005 Albuquerque Tribune.

I have this theory. Well, it’s really more of a hypothesis. Theory, hypothesis – what’s the difference you and many others might ask? And that’s precisely my point. I see a general lack of understanding of how these terms are used by the sciences versus their use on a day-to-day basis by the general public.

In the sciences, a theory is a particular framework used to describe and understand the world around us. Such a framework is only recognized as a theory after a firm empirical basis for its body of knowledge has been established. This is done through such things as extensive and long-term experimentation and observation.

A theory is often initially generated from a hypothesis – a proposed explanation for an observed phenomenon or set of phenomena. This differs from conjecture, which is at best an untested guess based on anything from common sense, to religious mysticism, to that ache in your grandmother’s knee.

But people generally use these three terms interchangeably to refer to any type of speculation. So your eccentric friend’s “theory” that Elvis, JFK, and Princess Diana are all alive and well, residing in Nevada’s Area 51 awaiting transport to their home world in the Alpha Centauri star system is only a theory in the layman’s sense of the term.

For those who haven’t by now skipped to the sports pages, you may be wondering if my initial hypothesis regarding people’s lack of understanding of the scientific definitions is actually more of a conjecture. After all, I haven’t presented any data or observations to base it on.

Unfortunately, there is plenty of supporting data. Just look at any media story regarding the very public debate between Evolution and Intelligent Design (ID) – a debate that’s been playing out across the country. A comment by William Harris, a member of the Kansas Science Standards Committee, exemplifies this equal time argument for including ID in high school curricula: “Public science education is an institution. It appoints a teacher to be a referee among ideas. . . . Nobody would tolerate a football game where the referee was obviously biased.”[1]

In other words, we need to expose our students to all competing ideas, giving equal time and weight to each one. And after all, that does seem to be the most democratic thing to do. Right? What could be more American than that?

The problem with this line of reasoning is that Evolution and ID are NOT “scientifically” equal. Yes, Darwinian Evolution is a theory, but it’s a scientific theory. It has survived rigorous scientific testing for over 100 years and forms the scientific foundation of modern biology. Scientific debate regarding Evolutionary Theory centers on the details of how it occurred, not if it occurred.

At best, ID is a hypothesis – a supposition that a certain level of complexity belies an intelligent creator. At worst it’s mere conjecture. But if it is a hypothesis, it’s a poor one because it seeks to answer the ultimate question of why there is life – a question more suited for philosophy and religion than the empirically based sciences.

That there are “gaps” in our current knowledge of how life evolved doesn’t mean such phenomena are too complex to be explained by anything but an intelligent creator, whether that creator be Yahweh, Mother Earth, or some mad alien scientist from Alpha Centauri with too much time on his hands. The history of modern science is replete with examples of filling in such gaps.

Because of all this, the academic debate surrounding ID should play out at the university level, the traditional setting for debating new scientific hypotheses.

And this is why it’s important for the general public and primary school board members in New Mexico to have some understanding of the various meanings of theory and hypothesis. Otherwise, our high school science curricula are created in a state of scientific ignorance – doing our children and society as a whole a disservice. Of course this is all just a theory of mine – er, I mean hypothesis.

References

[1] Ellen Goodman. Round 2: Fighting Darwin. IndyStar.com: The Online Edition of the Indianapolis Star. May 12, 2005. http://www.indystar.com/apps/pbcs.dll/article?AID=/20050512/OPINION/505120387/1002.