Monday, January 30, 2006

Response to a commenter

Thanks to all who comment. Please pin your flag on my Frappr map if you get time. This is a response to a response to my post on the Horizon programme. There wasn't really room on Haloscan to put this there, so it has a post of its own!
The first is that [irreducible complexity] is not a positive test of design, it is a negative test for evolution. Even supposing for a second that irreducible complexity could be 'proven' (which it hasn't been) then it still would not be a positive proof for design, only a negative proof against evolution.
Okay, then. Let’s accept the truth of your statement, for the sake of argument. Where is this leading? If you are saying that irreducible complexity disproves evolution (which I would understand to be shorthand for random mutation and natural selection), then what is the alternative? Suppose we can disprove evolution. What do you think are the alternatives? It looks to me as though you are objecting to somebody arguing that the refutation of an ateleological position implies a teleology. To me that is simple logic – it is inherent in the meaning of the words. But if you think otherwise, then what do you see as the alternative?
The fact that Behe and Dembski seem to think that irreducible complexity is a sign of design is based on a logically flawed assumption that anything that is not currently and convincingly explained by evolution is therefore design. This is not correct.
What is not correct is your understanding of irreducible complexity – would I be right in saying that you haven’t actually read anything by the proponents of ID, and have only read the misrepresentations by its opponents? You apparently seem to think that irreducible complexity is a kind of “God of the gaps” theory - “We don’t know how it works, so God must have done it.” IC is not that - “God of the details” would be a better characterisation. A system is IC if it consists of multiple components, all of which have to be present for the system to work. An extension of this which kind of flows out of the consideration of the theory is that the significant thing is that the components are also well specified. For example, you could argue that a protein is IC because it consists of a chain of amino acids, many of which are required for it to function. But what is more significant is that the individual components of an IC system should themselves be complex and specified. This is how what Dembski wrote ties into what Behe wrote.

So the point is that the components are low probability – they aren’t likely to arise by chance. The likelihood of multiple components being present by chance (Behe) is lower than the universal probability bound (Dembski). Therefore chance is not a reasonable explanation.

This isn’t just my spin on it, by the way – the people who designed the Avida program (for example – see the paper linked in the sidebar of the blog) are no friends of ID, and they understand the argument. Which was why they wrote a paper which celebrated the fact that Avida was able to produce “irreducibly complex” systems – functions which required multiple components to be present before the system expressed itself. Unfortunately, what they failed to demonstrate was that biochemical systems were as simple as the artificial organisms they generated within Avida.
There is another extremely important option which has been left out by the ID proponents and which covers a vast amount of ground - the "We don't know" option (or as I prefer, the "We don't know YET" option).
You are right. It is possible that synthetic pathways will arise which will allow us to understand the precursors of what we now regard as IC systems – they can only be provisionally tagged as IC. In fact, not only does Behe acknowledge that possibility, there is an implicit challenge in his book to people to come up with step-by-step processes that would allow an IC system to arise. It doesn’t have to be the “right” one – obviously over billions of years, we can’t know what the actual right one is. But it does have to be one that works. In the context of the bacterial flagellum, for example, this would involve going further than simply saying, “Well, the TTSS is an obvious precursor” (see below).
I have not yet seen any positive proof of irreducible complexity, I have only seen "known mechanisms of evolution couldn't have done that" - which even if it were true (and it isn't) doesn't prove design.
Actually, as far as I know, there are no known mechanisms of evolution that produce any large scale changes in organisms at any level. The best we have at the moment is the evolution of things such as antifreeze glycoproteins in fish, and minor morphological changes in organisms. Perhaps if you know of known mechanisms of evolution that can do anything evolutionarily useful at all, you could share them with the rest of the world, which is still waiting.
The other major problem with irreducible complexity is that by its very definition it excludes some of the possible ways it could occur.

A quote that I agree with:

Although Professor Behe is adamant in his definition of irreducible complexity when he says a precursor “missing a part is by definition nonfunctional,” what he obviously means is that it will not function in the same way the system functions when all the parts are present. For example in the case of the bacterial flagellum, removal of a part may prevent it from acting as a rotary
motor. However, Professor Behe excludes, by definition, the possibility that a precursor to the bacterial flagellum functioned not as a rotary motor, but in some other way, for example as a secretory system.

This is a huge problem for Behe's irreducibly complexity. If one takes into account not just the possible rotary motor precursors to a bacterial flagellum, but other precursors that had different functions, then you can see that irreducible complexity does not stand up.

By excluding a possible path to reaching irreducible complexity, Behe has rendered it scientifically meaningless.
Actually, you are wrong. Again, you are presenting the typical arguments of opponents of ID. Behe hasn’t excluded “by definition” anything at all. What you are talking about (feel free to contradict me if I am wrong) is the argument that the Type III Secretory System is a precursor to the bacterial flagellum. This paper has already demonstrated the flaws in this hypothesis. To the best of my knowledge, there is no other hypothesis. Which is strange, really - “Darwin’s Black Box” was published about 10 years ago, and it would do a lot for the credibility of darwinist groups if they were able to land one knockout punch against it. But they haven’t. The motive is there. The weapon is there – a whole group of publications who would love to discredit proponents of ID. The opportunity is there. Yet there has been no crime. Doesn’t this tell you something about the real scientific standing of darwinism?
You say that irreducible complexity has not been refuted and I'm afraid you are wrong. It has. And emphatically so. Would you like me to deal with the rest of your 'evidence' as well?
If it has, then I haven’t come across the refutation, and nothing in your comment comes close to a refutation. I spent years looking for refutations of Behe before I became convinced that he had made a case that needed to be answered. Nothing I have seen since has come close to answering it. However, if you would like to “deal with” the rest of the case for ID, go ahead. There are many evolutionist groups who will bless you if you succeed – and if it looks like you can make a good case, I’m sure they’ll send money your way to help with your research as well.