Sunday, September 16, 2012

Double plus special

One of the reasons why I am so immediately recognizable as a very poor atheist is that I am always talking about stuff other than the non-existence of god. I have gone to some very modest trouble to re-gain my atheist cred by talking about the non-existence of god, and this post is another in that -probably futile- effort.

There is apparently a group of atheists who have moved beyond the simple non-existence of god, and onto atheism plus. I doubt they would ever accept me due to the fact that I spend way too much time talking about my personal humanist opinions, and not enough time getting down to the process of non-belief to move on from that to pluss-ness. I had once hoped to be a double-plus-good atheist, but then -y'know- you have kids and life and stuff gets in the way.

So the other day I'm being “taken down” by a creationist for my foolish ideas about evolution. Every once in a while I engage in such conversations. I do not do it often as it is irritating. Theoretically there are people who both understand evolution, and disbelieve it. Of those there may even be some who disbelieve evolution for rational reasons that can be communicated. All the evolution-deniers I've had the experience of talking with have argued from a position of ignorance; most have steadfastly maintained that evolution cannot be understood.

So most conversations with creationists start form the mutually accepted common ground of their ignorance in something I understand. Then, and this is when things become -for a brief instant- amusing, the creationist attempts to develop an argument that is supposed to prove that I don't understand evolution either.

The ignorance of the creationist is usually cloaked in a set of rhetorical constructs. For the sake of argument I will call these rhetorical constructs arguments. The argument I was presented with the other day was the improbability construct.

Most of the time an argument with any true believer (TB) will drift into whatever topic the TB wants to hear their voice talking about at any particular moment. Maintaining a focus on a particular topic can bore most TB into disinterest. It would be interesting to find a creationist that was honest enough to explain that they believed in creationism simply because they did not have the attention span needed to understand evolution.

The argument I was presented with was the “All this could not happen by chance” argument. For the sake of expediency I'll call this the infinite improbability argument (IIA).

There are things that are highly improbable, and we can describe that property.

Elementary probability is usually taught by relying on random number generators. One of the most popular is dice. Most professors trying to teach elementary probability will be heard saying something like this: “Roll a six-sided die, and the probability of getting any number is one divided by six”.

This translates to a probability of 0.16666... If we had a ten-sided die the probability would be 1/10 or 0.1. I don't know how to make a ten-sided die, but one can make a twenty-sided icosahedral die. If one marks two sides of the icosahedral die with each number between one and ten the probability of rolling any number with that die is 2/20 or 0.1 (the same as the theoretical ten-sided die).

I've always liked ten-sided dice because they make the arithmetic so much more transparent. This can be important when conversationally dealing with the IIA.

The next thing the elementary probability professor does is begin combining probabilities. There are a handful of simple tricks and games the professor refers to, and here is one: “The probability of rolling two specific numbers in a sequence is the product of rolling each of the number individually”.

In other words, the probability of rolling an eight and then another eight is 0.1X0.1 or 0.01. The longer the sequence the smaller the probability, and the probability decreases geometrically. One does not need a very long sequence to have a very low probability of ever rolling it...or does one?

There are about 32 million seconds in a year (31,536,000 in a non-leap year) so we would only expect to have a 0.33 probability of rolling a sequence with a one-in-a-hundred million probability in a year if it took about a second to roll the dice each time. A sequence with a one-in-a-hundred million probability is only eight numbers long. Add just nine more numbers to the sequence and there is only a 0.3 probability of rolling the sequence in a span of one billion years. That is only a seventeen-number long sequence. What about a sequence of thousands of numbers that captured the complexity of the human genome?

To keep the arithmetic under control I usually imagine a sequence of 100 numbers. This long a sequence is long enough to be virtually impossible, but short enough to handle on most pocket calculators.

It is interesting to point out that any roll of one hundred ten-sided dice will produce a sequence that is astronomically improbable. Yet once you roll the dice there in front of you is an astronomically improbable sequence. When you really think about it we are -each and every one of us- impossible, but here we are.

If we roll one ten-sided dice about 60 times we are almost certain to get any number we want off the die. In other words, if I want to roll a 10 it will probably take me less than 60 tries. If it takes me a second to roll a die once I will be almost certain to roll any number on that die in less than a minute.

If I roll the first number on a sequence, and then roll the second I can roll a 17-number sequence in about a quarter of an hour. Contrast that with well over one billion years if we roll them all at once and hope to see the sequence, and then re-roll all of them if we do not.

It should take less than two hours of sequential rolling to roll the impossible 100-number sequence.

In this way the same physical process of generating randomness allows accumulation of information in a non-random way to create an impossibly-complex set of information.

The IIA then becomes an argument about rules rather than intrinsic qualities of probability.


2 comments:

Anonymous said...

One thing that you didn’t explicitly refer to is parallelism. Molecules are so small they interact in massive numbers all over the Earth. Even highly improbably events become possible, because of the huge number of interacting molecules. Because life is a self replicating system, once it has started, it will tend to continue. It is actually very surprising that life doesn’t create itself all the time. Some scientists think it does, but that current life forms are simply too dominate and destroy it before it can get a foot hold.

Remember, you only need one instance of a self replicating chemical machine to be created. And from that all life can sprout.

adult onset atheist said...

Great point. I was speaking more to evolution than to biogenesis, but parallelism can greatly impact evolution as well. Once you have a system of genetic exchange the potential for concurrent selection of beneficial mutations increases. It is kinda like tossing multiple dice at once and then choosing them independently in the analogy I use.