Contrary to
Aristotle, chickens haven’t always existed. And contrary to Genesis, chickens
were not created instantaneously in either adult or egg form. Modern
evolutionary biology tells us that modern chickens evolved from red jungle
fowls in southeast Asia around 8000 years ago. But which came first? The chicken or
the chicken egg?
Chic is the name
I’ll assign to the first chicken. Around 8000 years ago, Chic hatched from an
egg laid by her (non-chicken) red jungle fowl mother. Since the egg that Chic hatched
from existed before Chic did, it seems like we can quickly settle the age-old
question. The chicken egg came first! Many philosophers and scientists have concluded
that the egg-first view is correct for empirical and conceptual reasons (Sorensen,
1992; Papineau, 2006). However, to arrive at the egg-first view, one must establish
that the egg that Chic hatched from was a chicken egg and not a red
jungle fowl egg. For if Chic hatched from a red jungle fowl egg, the chicken-first
view would prevail.
After being contacted
by a Disney representative working on the film Chicken Little, the philosopher
of science David Papineau offered the following as support for the egg-first view:
"I would
argue it's a chicken egg if it has a chicken in it. If a kangaroo laid an egg
from which an ostrich hatched, that would surely be an ostrich egg, not a
kangaroo egg. By this reasoning, the first chicken did indeed come from a
chicken egg, even though that egg didn't come from chickens."
Many might share
Papineau’s intuition. But his argument relies upon a principle that can be
called into question. In its general form, the principle could be formulated as
follows: if an embryo of species X hatches from an egg, then it’s an X egg.
I’ll call this the carrier principle.
Upon first glance,
one might find Papineau’s example to be intuitive and strong support for the
carrier principle. But our intuitions about what type of egg something is seems
to shift depending on the details. If I imagine a scenario where a kangaroo
lays an egg that looks like just an ostrich egg and an ostrich hatches from it,
I suspect most would quickly declare it to be an ostrich egg. But this
intuition could be generated merely by the association of ostriches with
ostrich-like eggs. Our familiarity with what ostrich eggs look like might make
it hard for us to view it as something else. Here are three unfamiliar
scenarios that both test and raise doubts about Papineau’s carrier principle.
Genetic
Engineering: Suppose in
the future, a kangaroo is genetically modified so that it lays hard shelled
eggs like birds do, but with a highly unique shape and color. Its eggs are lime
green with hexagonal plates. Suppose that at an early stage of development,
scientists were to create a small hole in one of the kangaroo’s eggs and
exchange the kangaroo embryo with an ostrich embryo. Eventually a healthy
ostrich hatches from the egg. According to the carrier principle, the egg was
an ostrich egg since an ostrich hatched from it. Additionally, the carrier
principle implies that the egg changed its type (from kangaroo egg to
ostrich egg) once the embryo exchange took place.
Divine
Intervention: Suppose that
God decided to use his supernatural powers to spontaneously generate a human
embryo inside of a large egg laid by an ostrich. Months go by and a human baby
hatches from the egg. The carrier principle implies that this baby did not
hatch from an ostrich egg. It hatched from a human egg.
Saltation: Suppose that a red jungle fowl were to
lay two eggs identical in size, shape, genetic profile, and except for the
embryo, the interior contents are also the same. The first egg contains a
normal ostrich embryo, but the second egg contained an embryo with several rare
mutations. The mutations significantly change the genome of the embryo to the
point that it constitutes a speciation event. So, the second egg contains the
embryo of a new species, the chicken. According the carrier principle, the eggs
are of different types even though the eggs themselves are identical.
There is an
alternative principle informed by embryology and the scientific study of eggs (i.e.
oogenesis) that supports the chicken-first view. Following Waller (1998), I’d
like to first distinguish between (chicken) eggs and (chicken) embryos. By
egg, I mean the white oval-shaped object produced by chickens that found in
many American refrigerators and by embryo, I mean the organism that typically
develops within the egg. This distinction is important because although chicken
embryos are typically carried within chicken eggs, they need not be. When it
comes to the first member of a new species, the egg is always a different
species than the embryo.
In this case, the
egg that Chic hatched from would have had the genetics of her mother, a red
jungle fowl. This is because, as Waller (1998) helpfully points out, the eggs are created prior to the embryo and
always have the same genetics as the mother. So, there is a scientific reason
for thinking that Chic hatched from a red jungle fowl egg. The alternative to
carrier principle, which I’ll dub the oogenetic principle states that if
egg x has the DNA of species y, then x is a y egg.
Why should we
prefer the oogenetic principle over the carrier principle? One reason is that the
oogenetic principle is informed by the of science of genetics and egg
development. A second reason is that it fares much better against hypothetical
counterexamples. The oogenetic principle tells us that most animals in the real
world hatched from eggs of the same species but it also has the virtue of being
consistent with the view that animals can hatch from eggs of different species
in cases of natural speciation, as well as divine intervention, and artificial
genetic engineering scenarios. The carrier principle should be resisted for it entails
that it’s (logically) impossible for a creature to hatch out of the egg
of another species.
In closing, I’ve
argued that the despite the initial intuitiveness and popularity of the egg-first
view, the chicken-first view has several advantages. For those who view this as
a purely semantic debate, you could eliminate the verbal dispute by following
Aristotle and making a distinction between two different kinds of eggs: chicken-produced
eggs and chicken-producing eggs (Jansen, 2006). If one specifies the
former, then the chicken came first. If one specifies the latter, then the egg
came first. The End.
Works cited
What came first,
the chicken or the egg? the definitive answer. (2006). Retrieved from
https://www.theguardian.com/science/2006/may/26/uknews
Jansen, Ludger
(2006). It’s Chicken and Eggs again: Vagueness, Quasi-Species, and Evolution.
Conceptus: Zeitschrift Fur Philosophie 36 (89):71-77.
Sorensen, R.
(2003). A Brief History of the Paradox: Philosophy and the Labyrinths
of the Mind. Oxford University Press.
Sorensen, R. A.
(1992). The egg came before the chicken. Mind, 101(403).
Waller, D. (1998).
The chicken and her egg. Mind, 107(428), 851-853.
