It is forever true that DNA is a double helix, true that if you are a chimpanzee (or an octopus or a kangaroo) [and] trace your ancestors back far enough you will eventually hit a shared ancestor. To a pedant, these are still hypotheses which might be falsified tomorrow. But they never will be.

A Devil's Chaplain: Reflections on Hope, Lies, Science, and Love, (pp. 17-18), Houghton Mifflin Company. 2003