Here I'll throw in a semi-related quote from Rob Dunn's post "Your Appendix Could Save Your Life":
Grendell’s results do not prove Parker is right. Science does not work that way. More tests, even true experiments, need to be done. Maybe there was something else that differed between individuals with and without their appendixes. Maybe the result only applies to the mostly white population Winthrop hospital serves. Maybe the immune system plays a more important or different role than Parker envisions. These “maybes” are part of what make science beautiful — the idea that each question, each test, and each day, lead to more questions. Every good question is a road that goes on forever, diverging and bounding forward, sometimes quickly, other times more slowly, as new paths emerge and some of the old ones run straight into brick walls.