Getting Outside Ourselves
The average lifespan of a Drosophila fruit fly is about 30 days. Imagine what it observes from its perspective: young humans, old humans, middle-aged humans, wandering through the world. No single fruit fly observes a human of one sort turning into another. From its "pre-theoretic" point of view, it only sees "types" of humans that are more or less "fixed" across time (the 30 days of its life). There's no direct evidence of human aging in any single fruit fly generation. Then a particularly clever fruit fly comes along and claims that -- all intuitions to the contrary -- one type of human can actually turn into another: little children can get taller, become adults, and then become gray and wizened. I understand how this might be difficult for fruit flies to accept. And yet it's true: people do age! We're in the exact same position with respect not to development, but to evolution. I understand why evolution (speciation, transmutation) is hard to believe. But a lack of imagination and openness to the evidence is no excuse in 2015. ...