Revisiting Kinds

Recently the issue of created 'kinds' came up on another blog, and in the comments that followed it became clear that I needed to explain myself in greater length than would work well for a comment. So I promised to do a post here.

As background, one of the longstanding scripture-based charges leveled at evolution has to do with the description of 'kinds' in the creation account (or accounts, for LDS). The argument is usually something like the following: According to the scriptures, God commanded the plants and animals to reproduce after their own kind. This means that they cannot be related by common descent, nor can their posterity become a different kind. Further, the inability of different species to interbreed--and the usual sterility of hybrids--shows that this is the case.

In a previous post, The Kind of Thing Not Found in Scripture, I made several points, three of which I will summarize here:

1. Although the claim is often made that the scriptures say that animals and plants are to reproduce after their own kind, the phrase "their own kind" never occurs in the scriptures. Rather, the earth or waters are commanded to bring forth various animals "after their kind."

2. Just a few chapters following the Creation in Genesis, the story of the Flood also refers to 'kinds' of animals, including "all the cattle after their kind." It is clear in this context that the term 'kind' is used to include similar varieties. In other words, Noah isn't gathering up platonic forms, he is gathering up varieties of cattle, fowls, etc.

3. In my opinion, interpreting the creation accounts to mean that God created platonic forms that were to reproduce but remain forever unchanged (within whatever parameters define a 'kind'), requires the imposition of assumptions on the text, since the text doesn't actually say anything about kinds remaining unchanged. I think a more conservative interpretation--with respect to the text--is simply that God commanded the earth and water to bring forth a variety of beasts, cattle, fowls, fish, etc, with the animals named serving as representative examples. No process or method is specified; God simply commands the desired outcome and it occurs.

Moving on, we should recognize that this issue arises at least partially because of our propensity to categorize things, as well as our heritage from Plato. As Richard Dawkins explained in The Ancestor's Tale (p.308):

Ernst Mayer, distinguished elder statesman of twentieth-century evolution, has blamed the delusion of discontinuity - under the philosophical name of Essentialism - as the main reason why evolutionary understanding came so late in human history. Plato, whose philosophy can be seen as the inspiration for Essentialism, believed that actual things are imperfect versions of an ideal archetype of their kind. Hanging somewhere in ideal space is an essential, perfect rabbit, which bears the same relation to a real rabbit as a mathematician's perfect circle bears to a circle drawn in the dust. To this day many people are imbued with the idea that sheep are sheep and goats are goats, and no species can give rise to another because to do so they'd have to change their 'essence.'

There is no such thing as essence.

No evolutionist thinks that modern species change into other modern species. Cats don't turn into dogs or vice versa. Rather, cats and dogs have evolved from a common ancestor, who lived tens of millions of years ago. If only all the intermediates were still alive, attempting to separate cats from dogs would be a doomed enterprise, as it is with the salamanders and the gulls [two examples of ring species--see below]. Far from being a question of ideal essences, separating cats from dogs turns out to be possible only because of the lucky (from the point of view of the essentialist) fact that the intermediates happen to be dead.

I don't know whether the ancient Hebrews held essentialist views or not. It seems like a natural human tendency, but I would not want to underestimate the power of culture. Whatever the case, Western civilization has certainly inherited essentialism.

There are several other issues that the 'own kind' argument might be conveying and I think it is important to deal with them separately.

1. The inability of species to interbreed and hybridize is evidence against evolution because it shows that there are boundaries between kinds.

Fertile hybrids are more common in plants than animals. Nevertheless, the inability of species to interbreed is not a challenge to evolution. Rather, it is the result of evolution. Speciation is most commonly thought to occur through a process of reproductive isolation. As a simplistic example, imagine a population of mice that become separated from the rest of their species. If they remain isolated for long enough, their genetics will diverge from each other until they can no longer interbreed, and they will be considered two species.

The point here is that the barriers between species are not a logical problem nor a mystery for evolution. Further, we can turn the issue around and ask: If successful interbreeding is God's definition of 'kinds' then what are we to make of ring species, where local populations can interbreed with their neighbors, but the ends of the continuum cannot interbreed? And if God is so particular about keeping 'kinds' separated, why should hybrids--fertile or infertile--be possible at all?

2. If all life is related by common descent, then all life is of one kind. However, the scriptures speak of multiple distinct kinds.

This is equivocation because the meaning of 'kind' changes in each sentence. It's like saying that if humans are divided into tribes (e.g. the 12 tribes of Israel), then they cannot all be related because otherwise there would only be one tribe. In order to make sense of this one has to specify what is meant by 'kind' or 'tribe'. For example, bottlenose dolphins are a kind of dolphin, but they are also a kind of toothed whale, which are a kind of cetacean, which (skipping some levels) are a kind of mammal, which are a kind of animal, which are a kind of multi-cellular organism, and so on. That the scriptures speak of 'kinds' in one context does not preclude more inclusive (or exclusive) groupings.

3. Certain Church leaders have interpreted the scriptures as teaching that all life is to reproduce after its own (unchanging) kind, and as supporting evidence they have pointed out that different species do not interbreed and their hybrids are often sterile. Therefore, that is what those scriptures mean.

If the most important factor in accepting this general argument is that it has been promoted by some Church leaders, then the ground has actually shifted to a faith-claim. The evidence and reasoning for or against this interpretation of scripture becomes irrelevant when a person stakes out their position as a faith-claim, which they are free to do.

None of this is to argue that the creation scriptures actually endorse evolution. The expectation that science and the scriptures should match up is called concordism. However, there are reasons to reject concordism, and when it comes to the creation accounts I tend to (which makes the points I have laid out above somewhat superfluous). Rather than explain this, I invite interested readers to peruse posts with the label scriptural concordism. If you read nothing else, please read Genesis in Context, Comparing Creation Accounts, and Rejecting Concordism.

In summary, the plant and animal 'kinds' of the creation accounts are only in conflict with evolution if one holds to rigid essentialism and scriptural concordism, with a dash of scriptural inerrancy.

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