The Inevitability of Evolution (Part II)

THE NEXT FALLACY in this series (after Part I) is failure to appreciate the scale of things: When some creationist says that “the odds” against a particular series of mutations are so enormous that … [blah, blah] … he fails to grasp the immensity of the time and numbers involved. What he’s doing in his mind is watching one creature and one line of its descendants, waiting for the mutations to appear. He’ll probably wait forever.

But in the case of bacteria, for example, there are (I’ve read) maybe 100 million (108) of the little darlings in only one cubic foot of sea water. The earth has 328,000,000 cubic miles of ocean water, which is 4.83 × 1019 cubic feet. That’s 4.83 x 1027 bacteria in the oceans. Each one divides every 30 minutes. There are 8,766 hours in a year, so every bacterium reproduces 17,532 times a year. This means there are 8.46 x 1031 bacterial reproductive acts every year. That’s a whole lot of reproducing and mutating going on. In a billion years — a span we can grasp but which is forbidden to creationists — it’s 8.46 x 1040 bacterial reproductive acts.

Because evolution works on such a large scale, we recognize the incredible enormity of the creationist’s blunder when he says: “I’ve been watching the bacteria in this petri dish for weeks, and no platypus has climbed out yet.” When we say “large scale,” we’re not indulging in puffery. Ten to the 40th power is a big number — a very big number. For comparison, the observable universe is estimated to be 2.6 x 1040 times as large as a nucleus of an atom. Numbers of this order of magnitude have provided endless fascination for scientists, as can be seen here: Dirac large numbers hypothesis. Now we can add to that collection of natural wonders the reproductive acts of bacteria in a billion years.

Regarding the time scale, Darwin understood its necessity, and recognized it as a potential problem, because the age of the sun (approximately 4.6 billion years) was not then known, and the most educated estimates at the time seemed woefully insufficient for evolution to have occured. Darwin wrote to Alfred Russel Wallace (the co-discoverer of natural selection) in 1869: “Thomson’s views of the recent age of the world have been for some time one of my sorest troubles …” The reference is to William Thompson, later Lord Kelvin. The full text of that letter can be found here: The life and letters of Charles Darwin. As we now know, the issue was resoundingly resolved in Darwin’s favor. A good discussion of the Darwin-Kelvin dispute is presented here: The Age of the Sun.

The alleged odds against a sequence of mutations melt away with so many possibilities existing every hour for an enormous span of years, especially when it’s realized that all a tiny mutation (one step in the sequence) needs to do is occur once. Thereafter it’s part of the world’s bio-inventory, and each of its offspring, growing increasingly numerous, has the same mutating odds that its ancestor did. Just as there were billions of opportunities per hour for the first step to happen, in a very short time there will be billions of opportunities per hour for the second step to be added to the first, and so on. These things don’t happen all at once. They don’t have to. They have time and numbers on their side.

Now consider DNA — a long string of hundreds of millions, sometimes billions of chemically bonded base pairs of atoms. The assembly of such a sequence is declared by creationists to be an impossible string of random coincidences — as if its existence were the sudden result of all those atoms, aimlessly moving around in distant locations, finding one incredible moment when they just happen to fly together and somehow assemble themselves into just the right string. But it doesn’t happen like that. It’s step by step, involving billions of events an hour over a huge scale of time.

It’s not strictly relevant to the fallacy under discussion, but we should briefly mention something that creationists often overlook when they insist that DNA is miraculous. Atoms don’t behave like a Teflon-coated ball-bearings. DNA is based on organic chemistry. Carbon atoms are very promiscuous. Long, complicated, carbon-based molecules form naturally. If the elements are present, you can’t really prevent it. Organic molecules have even been observed off the earth, in comets and interstellar dust clouds. Earth’s early oceans would probably have been full of them. Those are the building blocks from which more complex molecules can form. Before very long, the oceans are full of useful sub-assemblies that don’t need to be “invented” all over again. DNA doesn’t “defy the odds” to abruptly assemble itself from the random wandering of disassociated atoms; and imagining that it does only increases the creationists’ confusion about the odds against such structures.

The idea of building blocks ties in with the first fallacy we discussed earlier — collapsing the continuum. Whatever accumulated mutations you may have in your genetic configuration, you can stop thinking of them as mutations — they’re you. That’s the initial state as far as your offspring are concerned. Either a new mutation will appear or it won’t, and all the generations before you, going right back to the proverbial pond scum, are irrelevant in “computing the odds” of the future. The next generation, like the last, doesn’t start from ground zero. None of them do; none ever did. Over an immense time scale and after uncountable natural iterations, you have arrived at where you are today. It’s pointless to ponder the odds against the past, because the past has already happened. The future starts now; it’s based on the present which is a 100% certainty. How do you like those odds?

So now you know the second fallacy: thinking small, or failure to appreciate the scale of things. All creationists’ arguments that involve this fallacy are worthless. Evolution works. You can bet on it.

In Part III of this series we will consider another fallacious argument used by creationists: failure to appreciate the nature of biology.

Copyright © 2009. The Sensuous Curmudgeon. All rights reserved.

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2 responses to “The Inevitability of Evolution (Part II)

  1. Pingback: The Inevitability of Evolution (Part I) « The Sensuous Curmudgeon

  2. Pingback: Creationist Wisdom #98: Big Bang « The Sensuous Curmudgeon