The question Which came first? - The chicken or the egg? constitutes one of the most well-known logical dilemmas on causality.

A chicken and egg problem is a dilemma or a deadlock situation where one cannot provide either item because one lacks the other. For example, you cannot find a job without work experience, but you cannot get work experience without first having a job.

As with most problems, it is important to try to understand the question and a good place to start is by asking what is meant by 'the egg':

Common viewpoint

The egg is assumed to be a chicken egg. This is an obvious assumption given that the question implies that there is a link between the two.

If we assume that the egg is a chicken-egg then we have to define what is meant by a chicken-egg:

• A chicken will hatch from a chicken egg

i.e. An animal that was not a chicken laid the chicken-egg which contained the first ever chicken. In this case the egg came first.

• A chicken egg is the egg that a chicken lays

i.e. A chicken (that already existed) laid an egg (a chicken-egg). In this case the chicken came first.

• Both of the above definitions apply

i.e. An animal is considered a chicken only if it hatched from a chicken-egg, and an egg is only considered a chicken-egg if it was laid by a chicken.

The latter case may cause confusion because it suffers from the chicken and egg problem itself; one can't exist without the other. It can be solved, however, if it is accepted that the first animal with the full genetic makeup of a chicken laid the first chicken-egg; the animal that hatched from this egg would be the first chicken, even though its mother was the first chicken from a purely genetic point of view.

Another viewpoint

The egg is not assumed to be a chicken egg. In effect this changes the question to: "Which came first a chicken or an egg".

From a purely scientific point of view this question can be answered quite easily. It is difficult to decide when the egg began as any cell is sometimes called an egg. Let's call the egg the hard shell one, and the chicken the first feather covered animal.

Evolutionary scientists believe the first hard shell egg was the amniotic egg laid around 200 million years ago, and was laid by the animal who was the link between amphibians and reptiles. It was only after this egg that animals could breed away from the sea. Birds would emerge 50 million years after descending from theropod dinosaurs. The first dinosaur with feathers was the Archaeopteryx.

In this case, the first chicken must have been the mutant offspring of a proto-chicken that laid the first chicken's surrounding egg. That is, unless one defines a chicken egg as an egg which has been laid by a chicken.

The crux of the matter lies in the definition of 'chicken' (or, if you like, of 'egg'). We define what does and does not constitute a chicken after the fact. Any definition of the first chicken is purely arbitrary. The question 'which came first?' therefore ignores the reality of speciation. Which is the first chicken - or the first chicken egg - is purely a matter of definition.

Yet another viewpoint

The chicken versus egg controversy is, in fact, the Creation versus Evolution controversy in a nutshell. The counterpoint, therefore, to the above evolutionary viewpoint, is that the first chicken was created by the Creator, and then that first chicken laid the first egg. The assumption of either of these viewpoints is a classic case of begging the question, since to say the egg came first presupposes that a chicken would have to arise as a mutation from the afore-mentioned proto-chicken, whereas to say the chicken came first presupposes that the first chicken was a fully formed animal from the get-go.

And Yet Another viewpoint

One can answer the question inside the framework one is experiencing the question in, making the quest NOT abstract, but factual: Which came first - the chicken or the egg? Answer: The chicken came first - in this sentence! This also cleares any confusion one might entertain about which animal came before the egg in which culture - just by actually listening to the question. And if one feels like twisting things around a bit, just reverse the order: Which came first - egg or chicken? Answer: The egg came first - in this sentence.

It's hours and hours of good, clean fun!

See also:

• Catch 22 (logic)
• Automated highway system (An example of a situation to which chicken or the egg applies)
• Speciation (how new species are created)
• Bootstrapping compilers.

other game theory related

• Prisoner's dilemma
• Chicken game