Friday, May 28, 2010

A Much-Too-Credulous Review of Signature in the Cell

John Walker is a pretty bright guy who's done some interesting work, but in this review of Stephen Meyer's Signature in the Cell, he demonstrates insufficient skepticism about Meyer's claims.

He asks, where did the information to specify the first replicator come from?, and then follows with this non-sequitur: The simplest known free living organism (although you may quibble about this, given that it's a parasite) has a genome of 582,970 base pairs, or about one megabit (assuming two bits of information for each nucleotide, of which there are four possibilities).

Of course, this is silly. Nobody thinks the first replicator was anywhere near this complicated, or even that it necessarily had a "genome" based on DNA. Even the genetic code itself may have evolved. Hypotheses like the RNA World suggest that the first replicator might have consisted of only a few hundred base-pairs.

Oddly enough for someone who has worked in artificial life, Walker shows no sign of having read Koza's 1994 paper, which shows how self-replicators can emerge spontaneously and with high probability in computer simulations.

He then goes on to claim you find that in the finite time our universe has existed, you could have produced about 500 bits of structured, functional information by random search. The only problem? The term "structured, functional information" has no definition in the scientific literature - it's just babble invented by creationists like Dembski and Meyer. There's no sign that Walker has read any of the criticism of Dembski's work.

Walker goes on to give a definition of "structured, functional information" as "information which has a meaning expressed in a separate domain than its raw components". But then there are lots of examples of such information occurring in nature, such as varves. Varves are layers of sediment which encode yearly information about the environment in which they formed. Another example is Arctic ice cores, which encode essential information about climate that is being mined by climatologists today.

Finally, the notion of "meaning" is incoherent. Disagree? Then tell me which of the following strings have "meaning" and which do not:

#1:
001001001100011011111010010111010010111000100000100000100111

#2:
010100111011001100001111101011100101110011110110010000001101

#3:
101010101010101010101010101010101010101010101010101010101010

#4:
101111101111101110101110111110101111101110101110101110101001

If that's too easy for you, let's try another. List all the binary strings of length 10 that have "meaning", and explain, for each one, what the meaning is.

Bottom line: insufficient skepticism leads to credulous acceptance of bad ideas.

10 comments:

RBH said...

The last paragraph of the review:

I challenge you to read this and reject the hypothesis of intelligent design. If you reject it, then show how your alternative is more probable. I fully accept the hypothesis of intelligent design and have since I concluded more than a decade ago it's more probable than not that we're living in a simulation. We owe our existence to the Intelligent Designer who made us to be amusing. Let's hope she wins he Science Fair and doesn't turn it off!

The whimsical designer IDists occasionally invoke? (See also here.)

Mark said...

There is information in DNA.
There is information in a seismic signal.

One causes the assembly of a protein (maybe).
The other causes a needle to move in a certain manner.

What's the difference?

Anonymous said...

I challenge you to assert the hypothesis of intelligent design. If you assert it, then show how your alternative is more probable. That would mean, first of all, that you describe your alternative. How does intelligent design work, what does it do, when and where does it happen, who (or what) does it, ... and what might not just as likely happen as what did happen?

TomS

Bayesian Bouffant, FCD said...

He asks, where did the information to specify the first replicator come from?, and then follows with this non-sequitur: The simplest known free living organism (although you may quibble about this, given that it's a parasite) has a genome of 582,970 base pairs,...

The simplest modern automobile has thousands of precision parts, therefore the wheelbarrow could not have existed.

cody said...

I'd rather ask him what binary strings don't have "meaning", and how he could possibly know that. Working within Walker's definitions (as well as IDs), how does one show that something is meaningless? (Or in IDs case, functionless, or irreducibly complex.)

How do they know the nucleons in every atom don't have more than enough meaning to go around? Maybe all the meaning in my DNA is actually a massive reduction compared to the meaning inherent in the component parts! It's not like they can disprove this claim since "meaning" doesn't mean anything anyway.

George said...

"Then tell me which of the following strings have "meaning" and which do not:"

None of them do.
What I mean is that none of them have meaning if there is no one to interpret them.

All the examples you've given, if I recall correctly, of non-intelligent sources of information, require something to interpret that information.

Jeffrey Shallit said...

All the examples you've given, if I recall correctly, of non-intelligent sources of information, require something to interpret that information.

Wind speed and direction, precipitation, barometric pressure, etc. exist independently of any observer, so to say their existence "require[s] something" is simply silly.

You could make the same argument about DNA.

Jeffrey Shallit said...

And thanks for admitting that binary strings carry no meaning - I guess that means that Dembski's example binary string in his book that he claims does have "specified complexity" is wrong.

Juniper said...

Can't say the varve model never applies, but it might not always apply in cases where we generally thought it did:

"A model based on seasonal deposition, as stated by the varve theory, does not appear to pertain to the Fossil Lake sediments" --

Buchheim, H.P. and Benton, R., The Dynamics of Fossil Lake, National Park Service, Corvallis, Oregon, pp. 14-15, 1981.

Jeffrey Shallit said...

Good creationist response, Juniper!

In fact, varves are quite reliable indicators, if you take into account how they can be perturbed by human acitvity.