"I came first!" said the egg.
"Rubbish!" said the chicken.
"Without me you wouldn't exist," said the egg.
"No. Without me 'you' wouldn't exist," said the chicken.
A cockerel strutted into our fictitious scenario, stage right. "Without me 'neither of you' would exist," he said, puffing out his chest.
"I'm not having it," said the chicken.
"The point is you 'did' have it, sweetheart, and that's where junior here came from," said the cockerel, gesturing towards the egg.
The egg and the chicken pondered the cockerel's argument.
"Sorted!" said the cockerel, who knew a done deal when he saw one.