At which point does an egg of non-chicken become an egg of chicken?

Is a “chicken egg” an egg laid by a chicken, or an egg that will hatch into a chicken?

It’s an egg that will hatch into a chicken, since the “first” chicken must have hatched out of an egg that was laid and fertilized by two “non-chickens” whose DNA combined together to make a full-blown chicken. Of course it wasn’t actually just one egg, but really, no matter how you think about it, the egg came first.

I agree, and I’ve made the same argument. It’s perfectly valid, Unless the egg belongs to the creature who laid it, instead of the creature that hatched from it.

If the egg in question is a “proto-chicken’s egg” because it was laid by a proto-chicken, then the chicken would have come before the chicken egg.

No it wouldn’t. If we’re going to talk about the creation of chickens as happening at a single instance of egg-laying, the two progenitors of said first chicken would be proto-chickens whose DNA combined in the fertilized egg to make, for the first time ever, a chicken. Yes, it’s a chicken egg, because it contains a chicken, but it’s also a proto-chicken’s egg because it wasn’t laid by a full chicken. It couldn’t have been, they didn’t exist yet.

There is no question as to the biology. The first egg that would hatch a chicken was laid by a proto-chicken. The genetic mutation that delineated chicken from proto-chicken first existed in that egg.

By your argument, the status of the egg is dependent on what it contains.

Suppose that proto-chicken pair laid an egg. And instead of it hatching into a chicken, I ate it. This egg never became a chicken; it was only an egg. It couldn’t be a chicken egg, because it never contained a chicken. It could only be a proto-chicken egg.

The egg that the chicken hatched from only became a chicken egg once there was a chicken inside it. The chicken egg, therefore, could not precede the chicken.