This post was originally posted to Facebook. It was a response to a creationist friend who posted a video of another creationist attempting to discredit the usual set of scientific theories. I felt I should share it for others because I’m terminally optimistic, and I needed the outlet.

One recurring mistake made by creationists when trying to discredit science is this: it is assumed that science must observe every phenomenon a theory posits to take place in order for that theory to be considered valid. When a creationist says repeatedly that “there is no evidence for THEORY X”, he is oftentimes operating on his standard that every prediction of that theory must be tested. This is unreasonable for science to progress; worse, it’s shown itself to be unnecessary. The value of theory is that it is better than a library of observations; it gives greater insight into what’s actually happening.

To use an analogy: many of my students in an introductory physics course spent the beginning of the semester doing physics problems with arithmetic. They were literally throwing numbers around in ways that “made sense” to them until they arrived at an (often wrong) answer. To break them of this, I began asking questions that required some higher level thought. Instead of “how high on the wall does the projectile strike” given some set of initial conditions, I asked “what is the minimum speed with which the projectile must be fired in order to go over the wall.” Those that tried arithmetic quickly realized they’d have to trial-and-error it to get the answer, which would be silly.

The ones that solved the problem instead used the theory they had learned in class (2D kinematics, a purely descriptive part of classical mechanics), algebraically finding the speed I asked for. I then asked them how this speed changes with firing distance, and they could answer this question by looking at the symbolic answer. I even asked them how quickly this speed changes with a change in firing angle, effectively requiring a derivative.

When creationists demand evidence for every single facet or prediction of a theory, they are demanding that science do the arithmetic…for every variation of the problem the theory is addressing. This is unreasonable. Worse, it doesn’t really tell us much more information about the set of phenomena we are addressing, just like solving the same problem over and over again with different numbers doesn’t really give insight into what’s actually happening.

With a finite number of scientists working on a much larger set of problems (and growing, as we are able to probe more and more of nature), our limited resources are better spent proving the principles and then moving on, using those principles to discover ever more. Quantum mechanics has probably less direct evidence for it than biological evolution, but we didn’t waste time endlessly testing every boring case the theory presents. Instead, we took advantage of it to build materials that now allow the computer you are using to post emoticons on Facebook.

So, thank a theory…or something. And have a nice evening.