Another Flew over the cuckoo’s nest #5
In the chapter ATHEISM CALMLY CONSIDERED Antony Flew recounts Israeli scientist Gerald Schroeder‘s ‘point-by-point refutation’ of the ‘monkey theorem’, at a May 2004 symposium at New York University. I thought I’d dig a bit.
Fifth in a series responding to Antony Flew’s There is a god: How the world’s most notorious atheist changed his mind.1
Flew says this ‘monkey theorem’
defends the possibility of life arising by chance using the analogy of a multitude of monkeys banging away on computer keyboards and eventually ending up writing a Shakespearean sonnet.2
He says it has ‘been presented in a number of forms and variations’, but does not specify where, how and by whom.
A useful Wikipedia summary reveals a long history as a comparative image for depicting probabilities. (In pre-computer times the monkeys had to content themselves with typewriters.) In relation to evolutionary theory however only two names are particularly relevant: Thomas Henry Huxley and Richard Dawkins.
Unfortunately neither provides much support for a religious apologist’s argument. Huxley is said to have used the image in his legendary 1860 debate with Samuel Wilberforce, Anglican Bishop of Oxford, about Darwin’s Origin of Species. But there is no evidence – indeed commercial typewriters only began to emerge in the 1860s.
Richard Dawkins on the other hand does discuss the image in quite some depth in his The blind watchmaker (Chapter 3: Accumulating small change).3 But he actually uses the image to make very much the same point as Flew remembers Gerald Schroeder making – ie that the probability of a set of monkeys generating even a single line of Shakespeare in any feasibly available stretch of geological time is infinitesimally small. Compare for example:
Gerald Schroeder, quoted by Flew:
If you took the entire universe and converted it to computer chips – forget the monkeys – each one weighing a millionth of a gram and had each computer chip able to spin out 488 trials at, say, a million times a second; …It would still be off… by a factor of 10 to the 600th. You will never get a sonnet by chance…. Yet the world just thinks the monkeys can do it every time. [Emphasis added.]
Richard Dawkins, The blind watchmaker:
It isn’t difficult to calculate how long we should reasonably expect to wait for the random computer (or baby or monkey) to type METHINKS IT IS LIKE A WEASEL. … The chance of it getting the entire phrase of 28 characters right is (1/27) to the power 28, ie … about 1 in 10,000 million million million million million million…
The numbers are different but the point is the same. Who is this ‘world’ Gerald Schroeder refers to – Aunt Sally?
I will probably survive
Interestingly it is Dawkins whom Flew immediately goes on to discuss. He starts on firm, if uncontroversial ground:
…[N]atural selection does not positively produce anything. It only eliminates, or tends to eliminate, whatever is not competitive.
Agreed, it is the random variation which does the producing. But then he goes a bit off-track:
A variation does not need to bestow any actual competitive advantage in order the avoid elimination; it is enough that it does not burden its owner with any competitive disadvantage.
He then gives what he calls a ‘rather silly illustration’, imagining he has useless wings tucked under his coat, too weak to lift him off the ground. They do not help him escape predators or find food:
But as long as they don’t make me more vulnerable to predators, I will probably survive to reproduce and pass on my wings to my descendants.
The illustration is not so much silly as misleading. It ignores the intensity of competition, and the unforgiving economics of survival. The useless wings represent a waste of material and energy resources relative to the competition. Vulnerability to predators is not the only risk. Anything that reduces the individual’s relative efficiency in staying alive, finding mates and producing viable offspring will tend to be selected against.
In debates like this it is important to remember that, generally speaking, the overwhelming majority of individuals in the wild do not survive to reproduce. So in the wild, generally speaking, a lack of competitive advantage and a competitive disadvantage come to the same thing. In fact in a competitive struggle of all against all, that is probably true by definition. Flew’s ‘I will probably survive’ is a little disingenuous.
But we’ll leave that to next time.
© Chris Lawrence 2009.