Recently I was read a series of email exchanges between a good member of the church and a Utah political leader. The writer was mistakenly concerned that religion and evolution were at odds and argued that intelligent design should be taught as science. This person promoted a common argument against evolution seen in creationist attacks, but it shows a basic misunderstanding about evolution and presents a straw argument against evolution. They suggest evolutionists believe that random processes alone structure the universe and evolution is an argument about low probably events occurring. This argument assumes that evolutionists think that if an infinite number of monkeys, given infinite time, are put to typing on typewriters that eventually the complete works of Shakespeare will inevitably result. Of course, the Intelligent Design creationists then point out that it is so improbable as to be impossible, therefore evolution is false. I say give the monkeys a chance. Let’s set some monkeys to typing and see if evolution is true or not. Science is about experimentation and nobody has even done any monkey on typewriters work.
The trouble with this argument is that this misrepresents evolution so completely as to be almost a ludicrous caricature. It suggests that because evolution works on random processes that the appearance of life on earth is a random probabilistic event.
Do evolutionary thinkers honestly believe that DNA just appeared on earth just by random chance? No they do not. The power of evolution is that it is a mechanism that creates complexity from simplicity (creationist sometimes argue that the second law of thermodynamics prohibits simplicity from moving to complexity, however, remember that is true only of closed systems, the sun is pouring enormous energy into the Earth which allows the move from simplicity to complexity). Evolution does not start with a random string of DNA suddenly and probabilistically appearing ex nihilo. It starts with a simple system that can replicate itself. All it takes is one chemical that can copy itself—one molecule that produces a molecule just like itself, some random variation and a selective environment. Once that is in place then evolution can work its wonders.
This view of evolution as random events only does not engage the views of real biologists. The missing piece of this argument is that evolution occurs through selection on random processes, not that life is just a random event. The whole genius of Darwin was natural selection. Selection! Not just random processes willy-nilly creating life.
Evolution through natural selection is a sorting algorithm. Let’s take our Monkeys busily typing away at their typewriters (I actually saw a creationist attack on this by giving monkeys typewriters and watching them destroy the ill-fated machines–somehow this was supposed to show the absurdity of evolution. I think the reasoning the authors were going for was something along the lines of (A) Since monkeys could never type at all, then (B) they could never produce Shakespeare, hence evolution is false since it relies on something Huxley is supposed to have said about monkeys typing.) Now, just as a point of clarification, Huxley never said this to Bishop Wilberforce in their famous debate, but let’s go with the analogy anyway. Evolution does not just argue that the complexity of life just jumped from nowhere in some probabilistic leap from the void, rather it argues that selection acts on random variation. Moreover, once something arises through random mutation that is adaptive it keeps it. So instead, as this author argues, of our waiting around for the monkeys to type the sonnet by randomly pecking at the keys, which we agree is not very likely, we get to keep those that fit the pattern provided by the sonnet. So suppose that every time a monkey hits a letter that belongs in the appropriate place in the sonnet our sorting algorithm keeps it. So for example, if our monkey hits an ‘a’ in the place where there is supposed to be an ‘a’ in the sonnet then it remains. I show below that it only takes about 240,000 key strokes under selection to get our sonnet. Far less than the 1/30527 you obtain get in the creationist attack as the probability of getting the sonnet. Interestingly, the probability of the monkey’s getting the sonnet? Probability = 1. It’s inevitable under Darwinian selection. (For a more complete assessment of how long it would take to get the 1000 lines of Shakespeare see the end of this Blog) We could even add a mutation rate and still get our monkey-typed sonnet in a reasonable time. (In fact, in Richard Dawkins Book The Blind Watchmaker he programs this process on his computer and gets lines from Shakespeare very rapidly using random variation with selection.) The point is that if you add selection to a process, very improbable events can jump to inevitable. And evolution is all about selection. In biological evolution, it is the environment that decides what is kept rather than someone watching the keys, but the principal is the same. So when selection acts in combination with random variation (our monkeys typing) the wondrous adaptations we see in the natural world are not infinitely unlikely. No. Using the power of evolution, these things can be explained quite easily. In fact evolution is currently being used to solve intractable mathematical problems that were thought to be unsolvable. In fact, software engineers use evolution to solve real-world problems; complex programs are evolved to solve engineering and mathematical problems by using random variation, inheritance, and selection—the only necessary ingredients for evolution.
Our best religion and science are compatible. Intelligent Design adds nothing useful to either.
Appendix A (you don’t have to read this: it’s math).
How long would it take the Monkeys to type out a Shakespearean sonnet under Darwinian Selection?
Consider an N character sonnet (or any given string of N characters). Now for each of those characters, the probability that the monkey’s key stroke will match the required letter in the i_th place is 1/(number of letters) for each position. Call this s. I’m assuming here that each of the monkey’s keystrokes is independent, uniformly distributed. For simplicity sake let’s assume that the monkeys complete a discrete round of N characters every T seconds call these rounds 1, 2, . . ., j, . . .t. (if you assume continuous typing it can only reduce the time it take to reach the sonnet i.e. this is a conservative assumption). Now assume every time the monkey’s stroke matches the character in position i, that that character is fixed, i.e., selection acts to keep that character because it matches the character in that string (like gene that produces a trait that fits in the current environment). Therefore, in the first round (1- s)*N characters remain unfixed and remain the same in all the rounds thereafter. In the second round there will be (1- s)*N*(1- s) or (1- s)^2*N unfixed. Using induction it can be shown (yes mathematicians talk this way! Not ‘I show’, but it can be shown!) that in the tth round there will be (1- s)^t*N characters that remain to be fixed. The time until fixation of the entire sonnet then is when s^t*N < 1, there are less than 1 characters needing to be fixed and no characters remaining to be fixed. At that time the monkey’s typing matches the desired string. Algebraically, this can be shown to be when t > ln(1/N)/ln(1- s). Let’s consider a sonnet of 1000 characters and with about 30 characters in the alphabet (I’m including some punctuation): then s = 1/30, N = 1000 and so our Monkeys will reach their goal in about 204 rounds or about 240,000 key strokes if they uselessly pound on fixed position keys or 28,972 if they quit hitting keys that have become fixed. As you can see it is no problem to get a sonnet for ambitious monkeys, a sorting algorithm, and some random variation. Monkeys prove evolution again! Doesn’t it make you proud that our physical bodies came from such distinguished and versatile characters!