This is the third in my series of linked blog entries on my experience of being converted (or not) to intelligent design. Here I present the key arguments from the book What’s Darwin Got to do with it? by Robert Newman, John Wiester and Janet and Jonathan Moneymaker, and how I respond to them.
- You can’t necessarily argue from small scale to large – you can’t take the example of (say) all the different shapes and sizes of dogs and draw the conclusion that you can evolve something from a single cell to a complex mammal. Seems fair – certainly in physics you can apply the same rules to different scales. Micro-evolution accepted without question. Macro-evolution requires more evidence.
- Peppered moths aren’t enough either – the famous increase of dark peppered moths in the industrial revolution demonstrates selectivity, but not evolution of drastically different species. Can’t argue with this. (Similarly finch beaks.)
- Similarities between species doesn’t necessarily imply common descent rather than design – the fact, for instance, that many mammals have very similar skeletal structures etc. is true but not useful. The fact that all cars are pretty similar in layout doesn’t imply common descent rather than design.
- You can’t use the bad design argument – This is one I’ve been guilty of. You point out that if biological entities are designed, they aren’t perfectly designed. Look at our back-to-front optic nerves. Look at the panda’s thumb. Y-e-e-s – but this is a theological argument, not a scientific one. ID doesn’t say that an infallible God designed everything, just that there is evidence of design. (And let’s face it, some biological ‘design’ is very good at what it does.)
- Transitional fossils are few and far between – MY FIRST CRY FOR HELP. Is this true? I know it used to be, and also there could be other reasons for this than they don’t exist (e.g. transitions tended to coincide with geological circumstances that don’t suit laying down of fossils).
- Everything since the Cambrian explosion has been variations on those ‘basic designs’ – SECOND CRY FOR HELP. Is this true? The book alleges that ‘no animal phylum has appeared since [the Cambrian era].’ Is this just a function of the way phyla are defined?
- If SETI received a message that appeared to be designed, we would attribute it to intelligence, even though we have no evidence whatsoever of the existence of alien life. Why do we treat the possibility of intelligent design so differently? – Their best argument, I think – not for the correctness of ID, but for not dismissing it out of hand.
- What about irreducible complexity? – For me this turns out to be an argument against ID. The Victorian favourites the eye and the wing have both been shot to pieces; as far as I’m aware, the same has been done for ‘rotary motors’ propelling bacterial flagella. If irreducable complexity indicates design, you’d expect to see it all over, and you don’t.
Apart from my factual queries, what isn’t mentioned anywhere is the sheer timescale available for evolution to do its work. Between the 1950s and 1990s, the Russian geneticist Belyaev selectively bred Russian silver foxes for docile behavior and showed just how early man may have turned the wolf into a dog. In just 40 years he got from a fox to something very close to a dog. Imagine what you could do in a billion years.
The other missing argument is the remarkably large overlap in the information content of DNA between different species. It really doesn’t take too many changes to provide a change of species.
Overall, then, I feel we need to take ID seriously, unlike creationism, because there is reasonable inferential evidence that is worth considering. And I will stop using the ‘bad design’ argument – that’s not a scientific argument. But going on what this book can tell me I’m not persuaded that there is any reason why we couldn’t see the changes an evolutionary model implies producing the variety of animals and plants we see today.
Continues:
Station #4
Station #5
Transitional fossils are few and far between – MY FIRST CRY FOR HELP. Is this true?
Yes. See this paper for a good, recent example. There is a problem, though, with ‘transitional’ fossils, as follows. In a sense they do not exist except in hindsight. As I have said elsewhere, evolution has no memory and no foresight, and only exists in the moment. Although we can pick up trends in the fossil recod after the fact, this doesn’t mean that evolution runs on some kind of pre-ordained rails. I think creationists of all stripes think that that’s how evolution works. Many evolutionary biologists certainly seem to think like that, or did until recently. This is not to deny that evolution happens, only to state trhat we should be more rigorous in defining what evolution is. Nevertheless, when I debunked the notion of progressive evolution in my book Deep Time there were howls of protest from evolutionary biologists complaining that I was giving ammo to the creationists. The existence of creationism has, to that extent, eroded free thought among evolutionary biologists, and this is something to be deplored.
Everything since the Cambrian explosion has been variations on those ‘basic designs’ – SECOND CRY FOR HELP. Is this true? The book alleges that ‘no animal phylum has appeared since [the Cambrian era].’ Is this just a function of the way phyla are defined?
No, this is pretty much true.
Ah, you need to browse the Index to Creationist Claims. To whit:
1 Note to Maxine: these are not unicycling girrafe, hence the spelling.
An interesting exercise Brian – there is much to ponder. But I have work to do (and it’s not really my field) so, for now…
You can’t use the bad design argument
Why not? If the ‘hypothesis’ is that the designer is intelligent, then make-shift solutions (e.g. the back-to-front optic nerve that you mention) are an observation that fits more with the notion of contingent evolution that pre-meditated design. The argument isn’t about which view is right, but which one is a more promising hypothesis, that merits investigation.
I agree we need to take ID seriously but see it more as a threat to science than a science in itself. In your reading have you found one testable hypothesis that it has thrown up, as opposed to a bunch of teleological arguments?
By ‘yes’, I of course meant ‘no’. Just testing.
Stephen –
I’ve frequently used the ‘bad design’ argument, but I do now accept that this is a theological argument and inappropriate. My video recorder is allegedly designed, yet I can point out several makeshift solutions and one or two out-and-out stupid aspects of the design. These don’t preclude it being designed. If, however, I was asserting it was designed by an omnipotent God I could make the theological argument that it was pretty shabby.
As I’m not an ID supporter I can’t actually say what hypothesis they would put forward, but I assume it would be in the area that some kind of intelligence has been involved in the design of lifeforms on the Earth, at levels to be defined by them. The initial prompt for this is inference, which I think they rightly point out is something we are happier to accept as a starting point in cosmology or in treating SETI as a scientific exercise.
Of course, given that position, the scientific community should then be looking for appropriate corroboration, but they don’t because they won’t consider ID.
I want to emphasize again I’m not supporting ID in any way – I just feel that it has not been treated from a normal scientific stance because no one is prepared to try to have a neutral viewpoint.
But, for most (all?) ID supporters, isn’t there is an omnipotent being lurking in the background? At the end of the day, this debate inevitably boils down to theology and each person’s individual response to the mystery of existence.
I don’t completely accept the arguments about cosmology or SETI since any inferences drawn are conditional on subsequent experimental testing. And that is the key point – these inferences lead directly to experimental tests (e.g. accelerator physics, the search for signals with information content). From what I’ve seen, ID doesn’t seem to take us in that direction. Where are the particular hypotheses and what are the experiments that they lead to? If ID wants to play the science game, doesn’t it have to follow the rules?
That depends on their audience. The official position is that ID says nothing about the designer, so they don’t write books with titles like Intelligent Design: The Bridge Between Science and Theology (Oops).
If one is to take ID at face value, the imperfect design argument isn’t an argument against ID. On the other hand it might provide a possible approach to identifying some aspects of the designer. But if they go in that direction, they might lose the Christians who support ID because they believe the designer is their god. All they would have left are the Pleasurians:
Stephen –
But, for most (all?) ID supporters, isn’t there is an omnipotent being lurking in the background?
I’m taking ID at face value, which means not making assumptions about other people’s beliefs, purely taking their arguments. What you say may be true, but it’s not about science.
I don’t completely accept the arguments about cosmology or SETI since any inferences drawn are conditional on subsequent experimental testing.
Absolutely, and any inference drawn from apparent intelligent design should also be conditional on subsequent experimental testing as much as is possible. (There’s still plenty of cosmology that isn’t capable of experimental testing, even something as basic as standard candles (unless you have an FTL drive about your person).)
However, playing devil’s advocate as I am, science tends to reject something like ID out of hand because ‘we all know what kind of people they are’. (Great science, that.) We don’t even allow the inference to be taken forward for further analysis/testing. I’m just trying to be scrupulously fair, so should I come to an anti-ID position at the end of this process, I’m not accused of pre-judging.
However, playing devil’s advocate as I am, science tends to reject something like ID out of hand because ‘we all know what kind of people they are’.
I agree it is important for scientists not to appear dogmatic on this issue. Some may certainly have dismissed ID out of hand but in other cases, the objections are well-considered. I return to my question: if ID is to be treated as a science, we can only appraise it by its outputs, so where are the insightful hypotheses and the experiments to test them? Are you saving that for post #4?
Answering the cries for help!
On #5: It has never been true that transitional fossils are few and far between. It’s become something of an urban legend, like the story that we use only 10% of our brains.
See, for instance, the Transitional Vertebrates FAQ from talkorigins.org — talkorigins.org/faqs/faq-transitional.html
On #6: This is pretty much true. All the animal phyla known today, more or less, appeared in a geological fingersnap at the beginning of the Cambrian. A quick version of a possible “darwinistic” explanation: Perhaps the beginning of the Cambrian was the first time a eukaryotic cell figured out how to work together with its daughter cells to form an organism with specialized parts; perhaps no new phyla have arisen since then because they can’t compete with the “big boys,” the phyla that have been around a while and are now much more sophisticated. Or perhaps no single-celled eukaryote has figured it out since that one at the beginning of the Cambrian. It took about a billion years, after all, between the first eukaryotes and that clever one that started the Cambrian explosion.
Also, remember that every new transitional fossil we find creates two new “gaps” that have to be filled with new transitional fossils. The creationist thinking goes like this:
Oh, so you guys found a fossil that’s a transitional form between reptiles and birds? Well done. Now go out and find a transitional form between reptiles and your new fossil, and another transitional form that lies between your new fossil and modern birds. Oh, you can’t find them? Evolution must not be true.
By far the largest body of evidence for evolution and common descent is homology in extant genomes. This dwarfs everything else combined by many orders of magnitude of orders of magnitude.
What is the (very crude) likelihood that two organisms are not related?
There are extant organisms that share substantial DNA. The only way they can share DNA is if they are related and so are descended from a common ancestor. In the case of organisms in the same species, that they share ancestors is not controversial. In the case of different species, the inference that two organisms that share DNA have a common ancestor is an extremely strong one.
To put some probability bounds on the likelihood, suppose two organisms have genes coding for 20,000 proteins and each of those proteins is 500 amino acids long or 10 million amino acids. If those organisms were unrelated, we would expect the amino acids in the proteins to have a nearly random sequence. Since there are about 20 amino acids, the chance of any two proteins having “the same” amino acid in the same place is about 1 in 20. That is, you would expect about 1 in 20 amino acids to be the same just by chance.
The probability of two unrelated organisms having 100% “the same” amino acids would be [(1/20)^10,000,000^]/[(1/20)^500,000^].
If the two organisms share 99% identity in those amino acids, that is 9.9 million amino acids that are “the same” the probability that this arose by chance is approximately [(1/20)^9,900,000^]/[(1/20)^500,000^].
If the two organisms share 90% identity in those amino acids, that is 9 million amino acids that are “the same” the probability that this arose by chance is approximately [(1/20)^9,000,000^]/[(1/20)^500,000^]. The probability that 90% identity arose by chance is greater than the probability that 99% or 100% identity arose by chance, but the magnitude of that difference is still so close to zero that the likelihood that two organisms that share 90% identity do so because of mere chance is vanishingly small. The leading zeros would take thousands of pages to write without scientific notation.
Pretending this degree of relatedness universally observed in the DNA sequence of all extant organisms is not evidence for common descent is disingenuous. There can’t be common descent without de novo speciation due to mutations and other genetic changes unless you assume intervention of a designer at each and every speciation event.
There has yet to be found a single organism or even a single gene that doesn’t fit the common descent paradigm. It might be argued that proteins doing “the same” things need to be similar. The only parts of enzymes that need to be “the same” for similar function are the amino acids that comprise the active site. Virtually all of the other amino acids are just space holders and their composition doesn’t matter. The only “purpose” such similarity would have would be to trick people who sequence it into thinking it evolved from a common ancestor. It would take a great deal of effort for the IDer to make the DNA of all organisms have the precise degree of similarity necessary to simulate common descent so well. Actually it takes vastly more effort to be deceptive because the vast majority of amino acids don’t matter. The IDer could have used any amino acids rather than the precise ones necessary to trick humans into thinking there was common descent.
This analysis only looks at DNA coding for proteins, there is much more non-coding DNA. Every additional sequence that is generated that is consistent with common descent is more evidence against ID. The probability of ID never becomes zero, but with a few thousand organisms sequenced, the probability that all the common DNA arose by chance is (very crudely) ([(1/20)5,000,000^]/[(1/20)^500,000^])^1,000 (for 1,000 sequenced organisms of 50% homology).
The likelihood of common descent being wrong decreases by a few thousand orders of magnitude every time another organism is sequenced and that organism’s DNA is consistent with common descent.