 Many times in debates between religious apologists and scientists I've heard the religious person defend his or her position by an insistence that evolution is a religion Darwinism, they say, takes as much faith as Christianity. Is that right? Is evolution a religion? Should we describe the positions of scientists as dogma? There's another related question that I've heard asked. Is science democratic? Isn't there room for debate on the issues of science? This is the public relations spin being used by the Christian apologetics legal defense fund called the Discovery Institute Teach the controversy or academic freedom. Is that right? Everybody likes freedom, of course, and hey scientists are supposed to be really open-minded. Why can't we teach both sides? Isn't that good science pedagogy? Is there a mainstream in science that resists these new ideas? Well, I'm a scientist a molecular biologist and I can tell you that we are not open-minded. We do not operate on democracy and we do have a central overriding principle we operate by. That overriding principle is expressed as one thing evidence. Science exists under the tyranny of evidence. That's the most important difference between religion and science. It doesn't accept anything. It can't test or prove. Faith never comes into it. There is no dogma in science. Every theory is tentative and only valued and proportioned to its ability to explain the evidence. Science is not interested in ultimate realities in explanations of meaning or purpose. All science can be reduced to accurate model building. Science is descriptive, predictive, and objective. Scientists who failed to bow to the tyranny of evidence are cast out. We have no room in our world for unsupported views. Many other videos have discussed the harsh gauntlet of peer review. This is where those who fail to support their views with adequate evidence are culled from the herd. It has nothing to do with how controversial an idea is, how fringe or revolutionary. If you have the evidence to back your claim. If your worst enemy can repeat your tests and get the same results. If no better explanation can be supported. Then your idea is accepted as a valid model until new evidence can be produced to challenge it. That's experimental science in one paragraph. I want to illustrate this with two different ideas. One is accepted science. The other is not. The first is the aquatic ape theory, which postulates that at some point in the ancient lineage of humans, one or more of our ancestor species may have lived in shallow water. This helps to explain why we, among the apes, have such unusual characteristics. We walk upright, are primarily bipedal, have almost hairless skin, have specific hair growth patterns, have a descended larynx, voluntary control of breeding, oily skin, a hooded nose, vestigial webbing between the fingers, and why our babies are born with a dive reflex. This is pretty amazing stuff, and does a pretty good job of explaining many of the features that puzzle us so much when we compare ourselves to our nearest living ancestors, the chimps, who are very poorly designed for an aquatic environment. There are dozens of other puzzles about the human line explained by this model, which has been championed by Elaine Morgan, a Welsh feminist writer. The idea has been wildly controversial among mainstream biologists. The second idea is the endosymbiotic theory. It's championed by another woman, Lynn Margulis, who was the first wife of the late great Carl Sagan. Endosymbiotic theory postulates that the origin of mitochondria, the eukaryotic organelle that is the site of energy production, and chloroplasts, the organelle that's the site of photosynthesis, both originated as separate prokaryotic cells. That is a key part of all of your cells is actually an ancient bacteria that learned to live inside a eukaryotic cell. This helps to explain a great deal about these organelles, but it also explains a great deal about the sudden emergence of large functional eukaryotic cells over such a short time. It proposes a new role for cooperation in the process of evolution that starts from the very first eukaryotic cell, even before multicellularity. This idea has been wildly controversial too. So there they are, the aquatic ape theory and the endosymbiotic theory. Both have much to commend them. Both explain phenomenon in the natural world, and both are controversial revolutionary ideas resisted by the mainstream. Now which is an accepted theory and which is not? Pause the video if you want to think it over. Can you decide on the argument alone? I certainly can. We need one more piece of this puzzle. The endosymbiotic theory has been tested and supported by mountains of evidence. Even the people who were the worst critics of the theory initially have changed their tune in light of the evidence and experimental testing for the theory. It's now in the biology textbooks of many high school students. The aquatic ape theory on the other hand, while it is a powerful idea, has failed to produce sufficient positive evidence to support it. That doesn't kill it as an idea, and it has provoked some useful discussion, but you won't see many references to it in the science literature. I happen to be quite fond of the idea of the aquatic ape, but I recognize that it has failed to meet the basic burdens of proof. Now when we take a look at intelligent design, does it fall into the same category as endosymbiotic theory, an idea that is controversial but well supported by evidence, or into the aquatic ape theory category, of an idea that is controversial but unsupported? A quick scan of the literature shows that they have failed to meet basic burdens of proof. Of course, they are only interested in the appearance of scientific debate, but they're missing a key point. Scientists don't debate ideas. We debate evidence, and they forgot to bring any. Philosophers debate ideas, and since the Discovery Institute is primarily composed of philosophers, perhaps they were unaware of the importance of evidentiary support. So why not teach the controversy in science class? Because there is no scientific controversy. There is only ideological controversy. Mathological naturalism versus theistic supernaturalism. Not evidence for one theory versus evidence for the other. What about academic freedom, the new rallying cry of the subverters of the Constitution at the Discovery Institute? There is an academic freedom to question whatever theory you like, and for the moment they call it science, they need to bring out the experimental evidence. Science tolerates no freedom in the face of evidence. This is not a free-for-all democracy of ideas. Not all ideas are equally valid in science, only those supported by evidence. What about strengths and weaknesses? Now that's a valid concept. We should debate the strengths and weaknesses of the evidence for a theory, but the debate needs to be between scientists who are actually familiar with the evidence, not high school students who have just covered DNA in a week and a half. The appropriate place for scientific matters to be resolved is in the science literature, not amongst 15 and 16 year olds in the first year biology class. And we shouldn't single out the theory of evolution. If we discuss strengths and weaknesses, we need to dissect and debate the cell theory, the germ theory, the atomic theory, the theory of gravity, and the many other ideas that passed critical review over 100 years ago. So, to conclude, scientists do not believe in the academic freedom of theories. We do not support a free-for-all of ideas, and we do not permit dogma to exist in our field. Anyone who attempts to advance science as a matter of faith is utterly destroyed. We live under a complete and utter tyrant who will permit no rivals. All hail King Evidence.