There are some questions that, by long enough vexing thinkers, become known as impossible paradoxes. Yet, as science rolls ahead, answers to these questions often become clear. In the popular imagination, however, the questions remain, philosophical koans defining the limits of our knowledge.

Take, for example, the proverbial chicken and egg.

Sure, it sounds impossible. But, given Darwin’s century-old insights, we can easily come up with a definitive answer.

First, what is an egg? According to most scientific texts, and echoed by Webster’s, it’s “the hard-shelled reproductive body produced by a bird.” That’s a key insight, as it defines an egg as something that comes out of a bird, rather than vice versa.

So imagine, if you will, a long line of bird-like organisms slowly evolving over time. One day, a new baby bird is born, a bird that combines its parent birds’ genes with new random mutations. This new bird is, in short, a chicken. It’s parents, however, weren’t chickens yet; they were close, but not quite. (And it doesn’t matter where, exactly, we draw that biological chicken/pre-chicken cutoff, so long as we know that it, definitionally, must exist.)

The mother, not being a chicken, didn’t produce a chicken egg – remember a chicken egg is an egg produced by a chicken. But her non-chicken egg held the first chicken nonetheless. A chicken who, in fact, might even ostensibly go on to lay her own first eggs – her own chicken eggs.

Which is to say, the chicken came first. Put that in your pipe and smoke it.