The full story about the chicken and the egg

As Yom Kippur approaches, the roosters make headlines, and we are interested in the chickens. So who came before whom, the egg or the chicken? And does this question - as ancient as the practice of atonement roughly - have an answer?

Written by: Zvi Atzmon, Young Galileo

The phrase "the chicken and the egg" is used to describe a situation of a "vicious circle", in which it is difficult to distinguish between cause and effect. For example: the teacher behaves harshly with his students - because they misbehave; The students misbehave - because the teacher treats them harshly.

What is a paradox?

The source of the expression is the ancient paradox: "Which came before whom - the egg or the chicken?" Why is this a paradox? And what is a paradox anyway?

Paradoxes are known in various fields: in philosophy, in logic (theory of logic), and also in mathematics and science. Paradoxes have different definitions. Paradoxes can be described as arguments that have a contradiction or point to a contradiction. The meaning is that the arguments of the paradox lead to two conclusions that contradict each other, or that the conclusions contradict what we know. The contradiction can be real or imagined. A mock contradiction is a contradiction in which a mistake can be pointed out (a mistake in assumptions or wording), but not always everyone agrees on the question of whether the contradiction is real or fake.

On the one hand, a hen lays eggs, from which chicks hatch; On the other hand, each hen herself hatched from an egg. Obviously there is a cycle here: chicken-egg-chicken-egg-chicken... Well, who came before whom: the egg or the chicken?

Why does this question point to a paradox? Because it leads to the conclusion that we know (or at least think we know) that it is not true. If every hen hatched from an egg laid by a hen, it is clear that every hen was preceded by a hen (she laid the egg from which this hen hatched). The same is true for a chicken that lived a thousand years ago - every chicken was preceded by a chicken. The so-called obvious conclusion is that chickens (laying eggs) existed even an infinitely long time ago.

Why is this a paradox? Because we know (or believe we know) that an infinitely long time ago there were no chickens at all. There are two possible sources for this knowledge: a religious-faith source and a scientific source.

The religion and science answer

According to the Jewish faith (based on the Book of Genesis), and following it also according to the two monotheistic religions that were based on Judaism - Christianity and Islam, the birds of all kinds were created on the fifth day of creation, and therefore before that there were no chickens at all.

According to the scientific approach, the entire universe known to us (known only in part) was created during the big bang. Billions of years after the big bang the earth was created. Living beings appeared on Earth only hundreds of millions of years after its creation. Only billions of years later did multicellular animals appear on Earth. Later, the vertebrates appeared - animals that have an internal skeleton made of bones and cartilage. Later, among the vertebrates, ammniotes developed - vertebrates whose embryos are equipped with an amniotic sac, which are adapted to life on land. Among the amniotes appeared the birds. From the fowl group the roosters evolved. One of these events is enough - certainly all together - to prove to us that chickens have not always existed, but only appeared at a certain point in the history of the universe.

If so, the paradox is this: if every chicken hatches from an egg, and every egg is laid by a hen, we must assume that the chain goes back in time to infinity. And we know that's not the case. So if the chain only started at a certain moment, who was really the first link in it: the egg or the chicken?

Whose egg is this?

The choice of chicken and egg is arbitrary. In the same way, for example, you can ask what came first: a sunflower seed, from which the sunflower sprouts and grows, or the sunflower, which produces sunflower seeds (these are its fruits)?

According to the Jewish faith, and following it also according to Christianity and Islam - the solution to the problem is completely clear: the egg-chicken-egg-chicken chain began at a certain moment in the history of creation - at the moment of the creation of the chickens (and the roosters). According to this approach, the chicken came before the egg. This can be reminiscent of the creation of man: although every boy and girl has a mother, Adam and Eve did not have a mother. This is reminiscent of an amusing riddle: which part of the body did Adam and Eve not have? The answer is an umbilical cord, because Adam and Eve were created, and did not develop in their mother's womb, and therefore they did not have an umbilical cord, and therefore they did not have a navel.

And according to science, what is the answer to the chicken and the egg problem? In the scientific context, two different questions must be distinguished. One: who came before whom, the egg or the chicken? And the other: who came before whom, the chicken's egg or the chicken itself?

The first question is very easy to answer: an egg existed before a chicken, because many creatures in the animal world have eggs: fish have eggs and amphibians like frogs have eggs, which appeared on earth long before chickens. And even if we limit ourselves only to eggs containing an amniotic sac, reptiles and dinosaurs already had eggs, which existed before the appearance of birds in general, and roosters in particular. If so, egg was before chicken.

However, the scientific answer to the question "Who came before whom, the chicken egg or the chicken itself?" different. In this case two sub-possibilities must be distinguished, depending on the question of what is meant by the term "chicken egg": Is the egg whose external characteristics are those of a hen's egg (hard calcareous shell, one sharp edge and one rounded edge)? Or does it mean an egg whose characteristics, including the internal ones, are like the characteristics of a chicken egg, meaning that the embryo in it is also a chicken embryo (since the egg is the place where the chicken embryo develops)?

If you mean an egg whose external characteristics are like a chicken's egg, it turns out that such characteristics were already present in the eggs of dinosaurs from the theropod group, which most researchers hypothesize are the ancestors of birds. But the similarity is only external: the embryos in the theropod eggs were theropod embryos, not chicken embryos.

What is a chicken?

Here we get to the heart of the problem: who came before whom, the chicken or a chicken egg with a chicken embryo inside? After all, the chicken embryo is a chicken itself. When it comes to a relatively small number of chicken generations, let's say ten generations, there is no visible difference in them, and therefore they are as if - only as if! - Part of an infinite chain that does not change. If we skip a very large number of generations back, and there we examine a chain of ten generations - again we will not see noticeable differences in those generations. However, between the ten early generations and the later ten generations we find clear differences; This is the process of evolution.

Let's imagine for a moment that a normal hen's egg, with a white shell, hatches into a hen, and when she reaches adulthood, she lays eggs with a blue shell, following a mutation that occurred in that hen when she was an embryo. Let's assume that all the chickens that hatched from the blue eggs will also lay eggs that have a blue shell. What is the stage in which the lineage of chickens that lay blue eggs was founded? Is the first blue egg? Or the white egg in the embryo in which the mutation to blue eggs occurred?

This is an imaginary example of a sharp transition: between white egg hens and blue egg hens. The evolutionary transition from a chicken that is not exactly a chicken to a chicken that is clearly a chicken is much more gradual and complex. Therefore, when someone asks you what came first - the hen's egg or the hen - ask him to describe precisely (down to the level of cells and molecules) what a chicken is, compared to a very, very similar chicken that is not a chicken, and likewise what exactly is a chicken egg - and only then answer him. If he doesn't have the possibility to give a completely accurate description (as is possible in the example of a blue egg versus a white egg), you don't have the possibility to answer him this ancient question, atonement for him.

The article was published in the Galileo Young Monthly for curious children. For a gift digital sheet Click

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