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Sci Tech
Huxley's hunch and simian Shakespeare
THE BIOLOGIST scholar Thomas Henry Huxley is supposed to have said in 1860 at a meeting of the British association in Oxford, UK that six monkeys typing randomly for millions of years could produce all of Shakespeare's works. Recently, Plymouth University UK, tried to put this idea to test. They let six monkeys type out whatever they wanted. Within a month, the monkeys chewed up the machines, used them as toilets and produced not a line of Shakespeare.
Writing about this in the June 14 issue of The Lancet, John Bignall found several things wrong with the whole thing. First of all he doubted whether Huxley said what he is quoted to have, since there were no typewriters in vogue in 1860. Secondly, had the keyboard contained not English letters (the QWERTY arrangement) but ideograms (e.g., a key denoting say, banana), perhaps the monkeys might have done better. Third, in defence of the monkeys, he says, "Just because we do things differently does not mean we cannot do them at all".
Put another way, perhaps one of the phrases or sentences typed out was Shakespearean in the simian (monkey) language and we humans could not recognise it as such. We in our anthropo-arrogance or human hubris dismissed it as garbage. Thus the whole Plymouth experiment was doomed from the start. Fourthly, Huxley wanted million years and Plymouth gave a month.
Methinks it is not possible
There are large issues here, which give us an insight into how biology has operated through evolution. Richard Dawkins points this out lucidly in his admirably written book The Blind Watchmaker. We see something in nature so exquisite and made-just-for-the-job, and wonder whether the random chance of nature alone could have produced it; should there not have been a `grand designer' behind it? Imagine an isolated beach, far from any civilization. You chance upon a watch with all its intricate parts that make it work. How could it have come about by chance? There must have been a watchmaker". This was the argument of the theologian Bishop Richard Paley. Dawkins argues that there is no need to invoke a `grand designer' who set out to make a living organism (or humans) to a purpose or with a goal. It evolved over a function of time, through generations of incremental changes. In other words, it is the product of a blind watchmaker.
How is one to understand this? Dawkins puts it thus. Take the monkey and the typewriter, and just one line from Hamlet — `Methinks it is like a weasel'. The sentence contains 28 characters (including spaces between words). Ask a monkey, or a baby (or program a computer) to type or hit 28 random keys of the keyboard. Example: " UMMK JK CDZZ F ZD DSDSKSM". This makes no sense at all. What do we do now? Discard it and try again: "JJKAUIZMZI UXDKIDISFUMDKUDXI" nonsense again. No matter how many trials hit, examine, discard, hit again- it is not going to work. The chances it will produce `Methinks it is like a weasel' can be calculated to be 1 in 27 (1/27) to the power 28, a time longer than the age of the solar system itself.
Single step versus cumulative selection
But evolution does not operate this way, using a single step selection. It does not discard and start all over. It works from what is there. The subsequent steps are made using the previous material. This is the crucial point. Evolution operates through cumulative selection, by accumulating small changes that occur over a long period of time. To illustrate this, Dawkins programmed his computer to start from, say, `WDLDMNLT DTJBKWIRZREZLMQCO P' and make changes to it, step by step, `breed' from it, or reproduce subsequent generations of sentences. Programmed in the computer language Basic, it took 43 generations for the machine to go from the above 28-letter-sequence to produce `METHINKS IT IS LIKE A WEASEL' in about 30 minutes. With Pascal as the language, it took 11 seconds.
This computer experiment shows an important feature of evolution. While the change in each step was made randomly, the cumulative process is actually non-random. Single step selection is random but cumulative selection is non-random, since it has to breed from its precursor. It also illustrates two aspects of evolution, namely reproduction and development.
Reproduction is creating an offspring out of a parent. It produces a copy of the parent (or parents) with little or no change. The information to do so is contained in the genes. Development introduces effects that are subtle changes. Reproduction passes genes and their features across to development, where they influence the growing rules. Development does not pass gene features back to reproduction. It is a one-way street.
All goals barred
In our example above, we have made the distinction between single step and cumulative selection. But the example is flawed because it had a long-term goal in mind (to make the sentence from Shakespeare). Evolution does not operate with a goal. The criterion for selection is strictly short-term either survival or more generally reproductive success. As Dawkins says "if after the eons, what looks like progress towards some distant goal seems, with hindsight, to have been achieved, this is always an incidental consequence of many generations of short-term selection.
The `watchmaker' that is cumulative natural selection is blind to the future and has no long-term goal ... no final perfection to serve as a criterion for selection, although human vanity cherishes the absurd notion that our species is the final goal of evolution".
In the event, changes that actually occurred between steps or generations, from first 28-letter-sequence above to the weasel sentence, involve mutations. They are permanent changes that carry through generations, unless other mutations mutate them. In the computer, we fast forwarded each of them and had the 43 generations occur in 43 minutes, with mutation in a minute. In real life, mutations occur over far longer time frames (of some times over a million years). Often, between steps or generations, there might be no mutations at all (a welcome relief, since we do not want our children mutated, at least for the bad).
This was the basis behind the Huxley time frame of million years for the monkeys to write Shakespeare. To get a feel of this, here is a dialogue. This man asks God: "My Lord, is it true that one second for you is a million human years"? God says, `Yes my son'. Man: "And one cent to you is a million human dollars?" `Yes'. "My Lord, please, may I have a cent?" "Yes, my son, in a second".
D. Balasubramanian
dbala@lvpei.org
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