Darwinian Evolution, Chance and Design

In a previous post, God, Darwinian Evolution and The Teleological Argument, I argued that evolution does not refute the teleological argument. Also, even if it did, a lot more significant philosophical work over and above any appeal to natural selection would be needed to infer from this that theism is rationally untenable. There is, however, a second concern lurking in this area; it is that Darwinian evolution shows that evolution occurs by chance. Chance is incompatible with design; hence, Darwinian evolution shows that biological organisms were not created by God. Del Ratzsch summarises the argument succinctly,

[I]f it is genuine evolution, then the theory itself demands that the processes be governed by natural law and random chance … On the other hand, if its genuinely guided [by God], then the process must involve not chance but deliberately designed intervention.[1]

The argument has two premises,

[1] If evolution is guided [by God] then the processes must not involve random chance;

[2] Genuine evolutionary theory demands that the processes be governed by natural law and random chance.

I think this argument is mistaken. To be a valid argument, the word “chance” would need to be used the same way in both premises. The kind of chance that is incompatible with creation in [1] would have to be the kind of chance that is part of genuine evolutionary theory in [2].

Alvin Plantinga has argued that when one examines how the word “chance” is being used in this kind of argument it is evident that the word is not being used the same way in both premises and that when the ambiguity is cleared up the kind of chance that is involved in contemporary evolutionary theory is compatible with the idea that God created human beings.[2]

Let us turn to the first premise; [1] the claim that if evolution is guided [by God] then the processes must not involve random chance. This statement is true only if chance is defined a certain way, both that its existence is incompatible with the idea that God caused the event to happen (either immediately or indirectly via normal secondary causation) and that God did so intentionally and with purpose. To say then that an event occurs by random chance, on this definition, is to say the event was not caused, intended or planned by God.

The problem is that if chance is defined this way premise [2] is false; genuine evolutionary theory does not demand that mutations are not caused by chance, when chance is defined in this way. According to Eliot Sober, when the word chance is used in the context of evolutionary theory it means, “there is no physical mechanism (either inside organisms or outside of them) that detects which mutations would be beneficial and causes those mutations to occur.” Ernest Mayr makes a similar point, “When it is said that mutation or variation is random, the statement simply means that there is no correlation between the production of new genotypes and the adaptational needs of an organism in a given environment.”

Defined in the manner of Mayr and Sober, chance is entirely compatible with the idea that evolution is caused, intended or planned by God. The fact that there is, “no correlation between the production of new genotypes and the adaptational needs of an organism in a given environment” and “no physical mechanism (either inside organisms or outside of them) that detects which mutations would be beneficial and causes those mutations to occur,” does not mean that the events had no cause and it certainly does not mean that they were not intentionally caused by God.

To show that evolution occurred by chance, where chance is incompatible with divine design, contemporary biologists would need to show not just that no physical mechanism detects which mutations are beneficial and causes them and it would have to do much more than fail to produce a correlation between the “production of new genotypes and the adaptational needs of an organism in a given environment.” It would have to show that there was ultimately no supernatural cause to the process that intended evolution of human life to occur. Contemporary biology has not done this and it is certainly very difficult to see how it could do so without stepping outside the bounds of science, as currently practised, and venturing into controversial areas of philosophy and theology.

[1] Del Ratzch Battle for Beginnings: Why Neither Side is Winning the Creation Evolution Debate (Downers Grove IL: Intervarsity Press, 1996).
[2] Alvin Plantinga “Evolution and Design” in For Faith and Clarity: Philosophical Contributions to Christian Theology ed. James Beilby (Grand Rapids: Baker Academic, 2006) 201-217.


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