The Lord regretted that he had made human beings on the earth, and his heart was deeply troubled. So the Lord said, “I will wipe from the face of the earth the human race I have created—and with them the animals, the birds and the creatures that move along the ground—for I regret that I have made them.”…
God said to Noah, “I am going to put an end to all people, for the earth is filled with violence because of them. I am surely going to destroy both them and the earth. So make yourself an ark of cypress wood; make rooms in it and coat it with pitch inside and out… I am going to bring floodwaters on the earth to destroy all life under the heavens, every creature that has the breath of life in it. Everything on earth will perish…. You are to bring into the ark two of all living creatures, male and female, to keep them alive with you. Two of every kind of bird, of every kind of animal and of every kind of creature that moves along the ground.”
Noah, now a vibrant and healthy 600 year old, builds the ark and spends close to a year floating on the floodwaters until his boat comes to rest on the mountains of Ararat in the caucasus. He releases his menagerie onto the slopes of mount Ararat, from where they head off to populate the Earth in an almost systematic effort to mimic a distribution of wildlife that would be best explained by allopatric speciation and long term isolation of populations.
These post-flood survivors are the ancestors of all living creatures on Earth today. All extant creatures are descended from these biblical kinds. Thus, the young earth creationist accepts “microevolution”; change within the limits set by “kind theory” more pretentiously called “baraminology”. So, the young earther agrees that from the lobe-finned fish kind, coelacanths and lungfish evolved. But a lungfish cannot evolve to become something that is not a lobe finned fish. That is, the young earther disputes “macroevolution”, evolution from one kind (a kind is roughly coextensive with the concept of species) to another. Between the lungfish and, say, the opossum, there is a taxonomic border that cannot be crossed.
This is an easy way for the young earther to deny common descent without having to deny the multitude of observations that show evolution in action (for example, the famous example of peppered moth evolution http://en.wikipedia.org/wiki/Peppered_moth_evolution). Kind theory allows Jesus freaks to reconcile the evolutionary change evident all around them with a fictitious tale of Noah, the 600 year old prophet and animal doctor.
The young earthers’ model of post-flood descent from “kinds” can be compared to the mainstream biological view of common descent in the below illustration:
Apart from the obviously more desirable element of simplicity in the common descent model (and the patently ridiculous scenario of a 600 year old man painstakingly collecting every single kind of terrestrial animal into a wooden boat, in which he keeps them fed and healthy, without finding land for the replenishment of supplies, for just under a year), there is another reason we should prefer the common descent model. The young earther has no answer to the following question in the theory of “baraminology”:
Why can’t the line between kinds be crossed? What mechanism prohibits “macroevolution” in theory?
Without a theoretically respectable answer to this question, it is unclear why we should believe the young earthers’ theory as opposed to the theory of common descent. We would only accept the theory that such an inviolable border between kinds existed if we already accepted the biblical account of special creation. Young earthers give us no reason to accept descent from kinds as opposed to the simpler (and better supported) common descent model.
We should not overlook the fact that the young earthers’ descent from kinds model is a more or less accurate description of the observed evolution of the last couple of thousand years. Within the last five thousand years or so, the descent from kinds model holds. We have only really witnessed evolution occur in small and gradual steps, which is totally in accordance with the young earthers’ descent from kinds model. In other words, in our everyday observation, descent from kinds is an accurate representation of the changes in the living creatures that we see. But notice that the descent from kinds model is simply a subset of the common descent model (We can see this in the illustration. The descent from kinds model corresponds to a snapshot of the upper portion of the common descent model). Thus, both the common descent and descent from kinds models paint more or less the same picture of what we should expect to see within the bounds of our recent experience. Both models tell us that nowadays changes in phenotype are small and intraspecific. But the common descent model takes that observable mechanism of small and intraspecific change in phenotype over time to account for all of the variety in living creatures. That is a very simple and testable explanation. The descent from kinds model, on the other hand, takes that very same observable mechanism to account for only a small amount of the observed variety of life, and then must posit an extra, untestable, special act of creation to explain the rest of the biological variety on Earth. On top of all that, the young earther also must posit another natural law forbidding any biological border crossings.
But this is all too philosophical. How about a nicer summary?
Q – What’s actually wrong with young earth creationism?
A– 600 year old men don’t exist.