Курица или яйцо: философская дилемма происхождения.

Philosophical paradox
the philosophical dilemma

The chicken or the egg causality dilemma is commonly stated as the question, "which came first: the chicken or the egg?" The dilemma stems from the observation that all chickens hatch from eggs and all chicken eggs are laid by chickens. "Chicken and egg" is a metaphoric adjective describing situations where it is not clear which of two events should be considered the cause and which should be considered the effect, to express a scenario of infinite regress, or to express the difficulty of sequencing actions where each seems to depend on others being done first. Plutarch posed the question as a philosophical matter in his essay "The Symposiacs", written in the 1st century CE.

The question represents an ancient folk paradox addressing the problem of origins and first cause. Aristotle, writing in the fourth century BCE, concluded that this was an infinite sequence, with no true origin. In the fifth century CE, Macrobius wrote that while the question seemed trivial, it "should be regarded as one of importance".

Although the question is typically used metaphorically, evolutionary biology provides literal answers, made possible by the Darwinian principle that species evolve over time, and thus that chickens had ancestors that were not chickens, In contrast, chickens are domesticated descendants of red junglefowl and probably arose little more than eight thousand years ago, at most. If the question refers to chicken eggs specifically, the answer is still the egg, but the explanation is more complicated. The process by which the chicken arose through the interbreeding and domestication of multiple species of wild jungle fowl is poorly understood, and the point at which this evolving organism became a chicken is a somewhat arbitrary distinction. Whatever criteria one chooses, an animal nearly identical to the modern chicken (i. e., a proto chicken) laid a fertilized egg that had DNA making it a modern chicken due to mutations in the mother's ovum, the father's sperm, or the fertilised zygote. It has been suggested that the actions of a protein found in modern chicken eggs may make the answer different. and finches suggests that such eggshell reinforcing proteins are common to all birds, and thus long predate the first chickens.