We can't be absolutely certain. Science doesn't purvey absolute truth. Science is a mechanism, a way of trying to improve your knowledge of nature. It's a system of testing your thoughts against the universe and seeing whether they match. This works not just for ordinary aspects of science, but for all of life.So, please, feel free to question evolution all you want, just back it up your objections with a few facts, evidence, and logic.My objection to fundamentalism is not that they are fundamentalists but that essentially they want me to be a fundamentalist too. Now they may say that I believe evolution is true and I want everyone to believe that evolution is true. But I don't want everyone to believe that evolution is true, I want them to study what we say about evolution and decide for themselves. Fundamentalists say they want to treat creationism on an equal basis. But they can't. It's not a science.