Wednesday, 9 September 2009

Outrunning The Tortoise

Back in classical Greece, where was a philosopher by the name Zeno existed. He listed 8 paradoxes that were preserved in the work of Aristotle. Possible the most famous paradox is Achilles and the Tortoise. The paradox does something like this:
In the paradox of Achilles and the Tortoise, Achilles is in a footrace with the tortoise. Achilles allows the tortoise a head start of 100 feet. If we suppose that each racer starts running at some constant speed (one very fast and one very slow), then after some finite time, Achilles will have run 100 feet, bringing him to the tortoise's starting point. During this time, the tortoise has run a much shorter distance, say, 10 feet. It will then take Achilles some further time to run that distance, by which time the tortoise will have advanced farther; and then more time still to reach this third point, while the tortoise moves ahead. Thus, whenever Achilles reaches somewhere the tortoise has been, he still has farther to go. Therefore, because there are an infinite number of points Achilles must reach where the tortoise has already been, he can never overtake the tortoise. Of course, simple experience tells us that Achilles will be able to overtake the tortoise, which is why this is a paradox.


There are scientific and mathematical objections to such reasoning, my favourite being that there's a finite limit to how low the sequence can go (can't get smaller than Plank time). But to me, the paradox serves as an apt analogy to the reasoning methods justifying intelligent design.

The analogy is as follows. The tortoise is God, it has the head start in the race. While science is Achilles, starting from scratch and rapidly progressing. While playing the role of Zeno is the intelligent design advocate, creating a "paradox" by which science will never overtake God as an explanation.

The pattern goes as follows. Define pattern X. Explain how X cannot come about by the current accepted processes. Point to instances in nature that fit pattern X. Therefore current accepted processes are bunk, conclude God did it. A proof by definitions, so who needs evidence?

A good example is irreducible complexity, it's a proof by definitions. Much like Achilles can't ever overtake the turtle because of the infinite series needed to overtake the turtle, natural selection can never explain how system which requires all components could be built gradually.

One can see that Achilles could overtake the turtle in a matter of seconds, but the paradox remains! Can irreducible complex systems evolve? Of course, and it has been known how for around 90 years now. In Behe's efforts to make a proof by definitions he neglected the scientific literature showing just how such systems could evolve.

Intelligent Design proponents are sitting on the sideline, yelling whatever they can to invalidate the obvious fact: Achilles overtook the tortoise long ago. So while mountains of papers are pouring into the scientific literature showing with more and more certainty that we evolved, the cdesign proponentsists are looking for a paradox of their own by which they can dismiss the volumes of evidence.

So much time is spent trying to talk about the inadequacies of natural selection, it's disbelief that Achilles could possibly overtake the turtle. That way, all they have to do is reject natural selection and design wins by default. No mechanism, no testing a hypothesis against evidence or making predictions, but that evolution can't explain it therefore God did it.

Every accumulated piece of scientific evidence in favour of evolution propels the theory further and further in the metaphorical race. Even when science starts from the null hypothesis and God from a presupposition, there hits a point where the accumulated evidence "outruns" the presuppositionist position. The evidence for evolution is overwhelming, so much so that all the cdesign proponentsistscan do is try to downplay it as "not enough evidence for me". Achilles has past the tortoise long ago...

6 comments:

Tomato Addict said...

It's funny how cdesign proponentsists can't bring themselves to talk about the definition of intelligent design. It's like they have a blind spot, or more likely turn a blind eye to the obvious truth.

Intelligent Designer said...

Kel,

Suppose that we find that mutation and natural selection aren't insufficient to cause evolution. What other options beside intelligent design are there?

From your perspective, what complex biological system has the most supporting evidence that it evolved? Please site a reference.

Kel said...

Suppose that we find that mutation and natural selection aren't insufficient to cause evolution. What other options beside intelligent design are there?If we knew the answer to that, we would be talking about that as an option ;)

Design hasn't shown any ability to make a predictive hypothesis. For all the complaints about natural selection being "just so", the entire history of thought on design has been nothing more than "It looks designed, therefore it's designed."


As for a complex biological system? Remind me in a couple of days if I haven't produced something. What criteria are you looking for? i.e. what kinds of structures, what kinds of citations? Should I just recommend you read Your Inner Fish and let Neil Shubin provide a book-length answer to such a question?

Intelligent Designer said...

So would you then agree that the options are as follows?

1) Evolution by mutation and natural selection

2) Sudden creation by intelligent design

3) Evolution by intelligent design

Kel said...

The evidence rules out special creation - the fossil record clearly shows that life has been on earth for at least 3 billion years. And genetics (among many other lines of evidence) clearly show common descent. The only way special creation could be plausible is if it's made to look like life evolved. That of course means contradicting the evidence even if true, so it ain't scientific.

As for guided evolution, it could happen. I of course can't rule it out, but this view is nothing more than conjecture until actual mechanisms are proposed and have been observed.

As regarding the option of unguided evolution, natural selection and mutation don't need to be the only forces at play. Even now we know better than to put those forces as the only mechanisms involved.


This logic is bad, and obviously so. Imagine asking Darwin this in 1859 - before neo-Darwinian synthesis. There was no discrete information in his theory. Would the trilemma then be:
natural selection
special creation
god-guided evolution
?
I think not.

Would 200 years ago be a trilemma between Lamarkian inheritance, special creation and god-guided evolution? Again I think not.


What I will say mutation / selection has going for it is observation. Mutation has been observed in nature, selection on mutation leading to adaptation has been observed in nature. The mechanisms of current evolutionary theory have been directly and indirectly observed to work.

Now that may or may not be the whole story, though right now it is all we have to work with. Any new hypothesis emerging on the question of how evolution works has to take into account all observations of life and explain what happens in that manner. Until such time modern evolutionary theory will remain as it is the only model so far that not only fits the evidence but makes predictive observations.

Kel said...

To clarify a bit further Randy...

What I mean by something new coming along is akin to what Einstein did for physics. It doesn't mean that Newton's laws were discarded, rather the limitations of them became apparent and are not used beyond what can be measured.

There's always the possibility of some new hypothesis changing the way we view a discipline. If that happens, then great. If not, then that's fine too.