Chicken or the egg

[3] Aristotle, writing in the fourth century BCE, concluded that this was an infinite sequence, with no true origin.

[3] Plutarch, writing four centuries later, specifically highlighted this question as bearing on a "great and weighty problem (whether the world had a beginning)".

[4] By the end of the 16th century, the well-known question seemed to have been regarded as settled in the Christian world, based on the origin story of the Bible.

[6] In contrast, chickens are domesticated descendants of red junglefowl and probably arose little more than eight thousand years ago, at most.

[10][11] However, the presence of OC-17 or a homolog in other species, such as turkeys[12] and finches[13] suggests that such eggshell-reinforcing proteins are common to all birds,[14] and thus long predate the first chickens.