I didn’t watch the debate about evolution and creationism between science educator Bill Nye and creationist Ken Ham this past Monday, but I have had a few general thoughts about this topic lately as this seems to have stirred up a necessary conversation about the nature of science.

Science is not a belief system. People mistakenly say that they believe in evolution but that is not an appropriate way to phrase it. We think that evolution provides the best explanation for the data we currently have on the diversity of life. It is an intellectual process that should be based entirely on what we can observe or measure. Of course, scientists are people too so they make mistakes in interpreting these observations and measurements, most of which are done honestly because we only have pieces of data rather than the whole picture. The scientific process over time corrects these mistakes especially as we gain new and better methods for observing/testing and as we fit together more pieces of the puzzle/world. Occasionally there are cases of outright fraud (see the autism-vaccine study, Hwang Woo-Suk’s fabricated stem cell research) or bad methodology that is politically motivated (the Regnerus study supposedly on gay parenting that wasn’t really). So we as scientists have an important role to play in being vigilant in peer-review and in repeating experiments to ensure the honesty of the results. But this is all part of the process.

Creationism (or intelligent design) is fundamentally untestable under this scientific famework. It is beyond the realm of the tools of science. It is entirely possible that a divine entity (or entities) did create everything, however this interpretation can never be disproved by science (because how can you completely eliminate the possibility of divine acts?). Contrary to popular belief, science actually works by disproving certain ideas, which then provides support for others. Nothing can be absolutely proven (which is true of all science, not just biology) so we work to disprove what we can.

It is so important that people understand that this is an intellectual process, not a faith or belief based one. If we find another idea that explains the data we see better than evolution then we move to that idea. Although it can be very hard to accept new ideas and it can take time until it is generally accepted; it does happen (for example the idea that mitochondria/chloroplasts have a prokaryotic origin, or the Ecdysozoa/Lophotrochozoa split, maybe the placement of ctenophores in the tree of life? The last one is one that we are currently working through and I don’t know what the answer will be yet).

But the fact is that so far, no other scientific ideas (remember that creationism is not a scientific idea) come even close to evolution in explaining the patterns we see. We don’t understand all the details of evolution, we understand the broad strokes of the process, but we are working on the details. Keep in mind that even something as fundamental to physics as gravity is in a similar situation, i.e. we understand what gravity does, but not really how it works, not in fine detail anyway. But even without the details, evolution does a pretty amazing job of explaining the patterns in the diversity of life we see on the earth. And in science, support is given to the idea that explains the most data. Until another idea that can be tested (and potentially disproven) comes along that explains more of the data than evolution does, then as a science, biology will have to stick to evolution.

Additionally, we benefit greatly from framing our scientific inquires this way. For example, studying agriculture and medicine within an evolutionary framework helps us find better ways to grow/breed crops or develop better/more effective medicines (and test them appropriately). If life is all designed by a creator, how does that help us better understand the world around us? I would argue that the framework of intelligent design is not useful for actual study, it does not allow us to make inferences that are important in driving forward our understanding of the world. For example, if a drug works one way in mice, how will it work in humans? With evolution you have a framework to evaluate this (the mouse is similar to humans in this way due to a common ancestor, but is different from humans in that way as a result of being a separate lineage for some amount of time, it’s important to understand the similarities and the differences in the context of drug testing). With intelligent design, we have the whims of a creator that might make some things similar but other things different. And ok, that’s fine, but how does that allow us to actually infer the likely effect of the drug in a human? To give another example, why does one animal respond differently to a pesticide when compared with another? Because God made them differently? How does that help us develop a pesticide that works on the insects we want it to and not on the ones we don’t?

People see science as a way to get at the “truth”, the exact reality of what happened historically and what is happening now. But scientific truth is not absolute truth. We all make observations about the world and science seeks to provide a framework through which we can come up with ideas that make sense of these observations (i.e. make hypotheses) and test them in a way that is repeatable by others again and again until we come to some consensus of what is the most likely explanation for the data. But because we can never absolutely prove anything in science, even the most likely explanation will have some uncertainty (we can’t prove that the explanation is true in all cases because we can’t test all cases). We can never know the absolute truth, we can only determine the most likely scenario given the data we have (and the data we have is always increasing which leads to changes in our ideas). The reality is that unless we have divine intervention, the exact accounting of the history of life, the earth, and the universe will always be unknown to us. Science just gives us the best guess (given what we know) and all (good) scientists have to make peace with this.

People are free to believe (i.e. accept as truth) what they want, but we cannot characterize all “truths” as scientific. Science has very specific parameters and some things (such as the divine) are simply beyond those parameters. And if certain explanations are beyond the parameters of science, then they are not helpful in moving forward our scientific understanding of the world around us. So why would we want to fundamentally change the definition of science (which is what you would have to do to teach intelligent design in a science class), to present an approach that doesn’t help us evaluate/make sense of the observed facts? If you want to teach creationism/intelligent design then it should be taught in a philosophy or religion class and not in a science class.

One last note on evolution. For those that despair about our organismal beginnings, admittedly, evolution does not speak to the origin of life at all. Evolution only speaks to the change that occurs once life is already here. There could be a deity that started life and allowed diversification to occur through evolution. Some people choose to integrate their faith with science in this way but again science cannot speak to the veracity of presence/influence of God here, which brings us full circle.

To conclude, science is a tool that helps us make sense of the world around us. But it is not an appropriate tool for all questions (such as questions related to divinity). Some questions will remain deeply personal (such as the meaning of life) as how each person decides to integrate their faith with what is objectively known to science will be always be a personal choice. But it is very important that we understand what science is and what it can and cannot do. Science provides us with one avenue that we can use to make our lives better (and hopefully the lives of other organisms too), but to use it, we have to understand it properly and not dilute its power with unscientific approaches.

Abigail Reft holds a MA in ecology and evolutionary biology from the University of Kansas and a PhD in evolution, ecology and organismal biology from Ohio State University. Her work has appeared in the Journal of Morphology, Conservation Biology, Biological bulletin, and The Nautilus, among others. She is currently a National Science Foundation postdoctoral fellow in biology and is continuing her work on the evolution of sea anemones and their relatives at the University of Heidelberg in Germany.