Friday, December 18, 2009

Darwin's Dilemmas: Essence Precedes Existence--Part 2

Historically philosophers viewed things as having a transcendant, more fundamental "essence" shared by all like things. Chairs have chairness. People have humanity. And the existence of these things depends upon their preexistent essences, or ideals, which truly exist in the metaphysical realm. Existentialists like Jean-Paul Sartre reversed this, saying instead, "existence precedes essence." To them, there is no real thing called an "essence"; there are merely things that exist, and what philosophers had previously called essences are merely categories imposed upon things by humans able to recognize similarity.

What does this have to do with biology? How are the theory of evolution and the philosophy of existentialism related? One might expect a Christian like myself would equate evolution with the philosophies often associated with it--such as materialism or atheism--and find the connection there, but one would be wrong. In fact, the philosophy of existentialism as summarized by the phrase, "existence precedes essence," is manifested in the very biological processes predicted in evolutionary theory.


Evolutionary biologists envision all species as having descended from a common ancestor, the first living organism. This first living organism reproduced, and eventually its offspring experienced a change in the hereditary information inherited from its parent. This change, the result of a mutation occurring during the copying of the parent's DNA, provided the organism some benefit, allowing it to survive better than its siblings and parents. And so on and so forth, life becoming increasingly diverse, resulting in the great diversity of life we see today.

This process of change over time, of all species sharing a common ancestor, is illustrated using a "tree of life." At the base the tree has a trunk, representative of the first living organism. Branches emerge from the trunk, representing those offspring which were ever so slightly different from their parent. Branches emerge from those branches, and so on and so forth.

Like existentialism's "existence precedes essence," according to this model there are no such things--not really--as kinds of organisms. There is no real kingdom, or phylum, or class, or order, or family, or genus, or species. These are merely categories humans impose upon creatures which are similar enough to be classified together. There is no "essence" of "what it is to be" an arthropod; there are simply creatures like lobsters and crabs which, by virtue of having soft insides and hard exoskeletons, are classified together using the name arthropoda in order to distinguish them from creatures which don't share these same properties.

So we see that the diversification of existing animals--existence--leads to the imposition of classifications--essence--upon them. "Existence precedes essence." But existentialism is not only apparent in evolutionary theory's conception of the "tree of life."


According to the theory of evolution, complex structures do not come about suddenly, fully formed, comprised of all their constituent parts. A creature was not suddenly born with eyeballs from a creature that had none. Instead, the parts that make up complex structures appeared gradually, over very long periods of time, bit-by-bit, over generations upon generations.

A random mutation in the copying of a parent organism's DNA might result in the offspring having one of a future complex structure's many parts. That individual part, by itself, provides the offspring with some benefit, making it better capable of surviving its environment. Thus, natural selection preserves that trait and it gets passed on to future generations. Some time later, this organism's DNA is further mutated during reproduction and its offspring manifests a second part. That part, in and of itself or in conjunction with the first part, again provides the offspring some benefit and both traits get preserved through future generations. This process continues, over millions of years and millions of generations, each part of a future complex structure coming into being by chance, piece-by-piece.

Again we see existentialism's "existence precedes essence" in action. Natural processes don't conceive of something called an eyeball, or an ear, or a brain, or a tail, or a stomach, and then put the pieces together. Instead, the pieces come about individually, without respect to one another, over long periods of time, and happen to form eventually into structures we give names to today. We call an eyeball an eyeball, but the concept of an eyeball--essence--came after the happenchance assembling of its randomly-produced parts--existence.


The Bible militates against this existential nature of the theory of evolution. Before God created anything, He conceived of it. He thought about it. He planned it. And upon deciding to bring into existence physically the creation He conceived of in His mind, He spoke it into existence:

Then God said, "Let the earth sprout vegetation, plants yielding seed, and fruit trees on the earth bearing fruit after their kind with seed in them"; and it was so. (Genesis 1:11)

Then God said, "Let the earth bring forth living creatures after their kind: cattle and creeping things and beasts of the earth after their kind"; and it was so. (Genesis 1:24)

Then God said, "Let Us make man in Our image, according to Our likeness; and let them rule over the fish of the sea and over the birds of the sky and over the cattle and over all the earth, and over every creeping thing that creeps on the earth." God created man in His own image... (Genesis 1:26-27)

God conceived of kinds of plants, and then brought them into existence according to those plans. He imagined kinds of animals, and then brought them into existence according to those plans. He devised a creature in His own image, and then brought man into existence according to that plan.

But what does the study of biology suggest? Does it confirm the theory of evolution and the existentialism woven into the very fabric of biological process responsible for the diversity of life? Stay tuned.

No comments:

Post a Comment