• I have been a biologist for a long time, and I hope I never stop getting shivers in my spine when I think about the beauty of how we come to know things in biology. Biologists make predictions, then they go out into the field or the lab to see if their predictions hold up. When hundreds of predictions of this sort are fulfilled, a theory reaches the point where it becomes certain, at least on a broad level. And that is where we are with evolution.