I have a sister who has a very smart daughter called Christina. She is only 3 years old and often curious about everything in everyday life. One day, I visited Christina, giving her a book titled “Baby's first 100 words” and I trusted she would like it very much.

When I came, Christina shouted with happiness. Particularly, she was so excited when seeing the book. “Let’s read the book together!” – Christina told me with her eyes twinkling.

We sat on the sofa, turning page by page. For every word, I pronounced it clearly and asked her to repeat. I also briefly explained a few basic things about the pictures to expand her knowledge. When she looked at the chicken and the egg in the book, she constantly cried out: “Wow, they look so cute!”.

- Christina, try to answer this question, and then I will buy you a chick! – I said.

- Yes, please!

- Do you know which came first, the chicken or the egg?

- Hmm, a chicken!

- Why?

- Because I see the chicken with the letter C first, and then the egg with the letter E.

- Oh, such a smart answer! – I was quite surprised.

- What do you think, which came first? – She was curious as she was always.

- Hmm, for me, the egg will come first, because I often eat the egg first for my breakfast, and then the chicken for lunch or dinner.

We all laughed loudly. Still within the discussion, Christina told me that as the chicken can run, it will come first in a race, whereas the egg cannot move. I argued, “The egg can roll to the finish line, but the chicken may walk to somewhere else, then finally the egg will come to the destination first”. I continued to explain that when people think about “egg” in a very general meaning, the answer is the egg came before the chicken. They think about the eggs of dinosaurs, the first creations in the world about 110 million years ago. Meanwhile, the chickens might be domesticated only around 10,000 years ago.

- Now, Christina, let’s think about the question seriously: “Which came first, the chicken or the chicken egg?”. Do you know that a proto-chicken that was a chicken-like bird? The proto-hen laid an egg which was fertilized by the proto-rooster, creating a mutation that made the baby different from its parents and became the ancestor of the chicken. In short, the egg came first and it hatched what we called a chicken nowadays.

I was not sure if Christina could understand what I explained later, but her answers were great. The answers to the question depend on the viewpoint and position of the respondents. Indeed, the question can take our head spin right off our neck, similarly to the fact that “A circle has no beginning”. To some extent, spending time and effort to identify the first and the last point of the circle will be a useless thing.