“Chicken or the egg?”

LORELAI: You need three highlighters?
RORY: Yes … One dries up, one gets lost, I have one left.
LORELAI: You have really thought this out.
RORY: Yes, I have.
LORELAI: What came first – the chicken or the egg?

The chicken or the egg is an ancient dilemma, whereby it isn’t clear which event occurred first, since chickens lay eggs, but the first chicken would need to come from an egg. Philosophers grappled with the problem for centuries, beginning with the ancient Greeks.

Evolutionary science tells us that the egg came first. Hard shelled eggs first appeared 312 million years ago, while the ancestors of the modern chicken arose perhaps 8000 years ago. Even the first chicken egg would have come before the chicken – laid by a creature that wasn’t a chicken.

Lorelai is jokingly saying that since Rory is so smart, she must be able to solve this ancient riddle.