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Author Topic:   Irreducible Complexity, Information Loss and Barry Hall's experiments
Wounded King
Member (Idle past 2291 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 118 of 136 (515778)
07-21-2009 4:32 AM
Reply to: Message 106 by Theodoric
07-20-2009 1:21 PM


Re: issues and how to resolve them
Hmm, if they are doing scientific research they ain't publishing anything.

Lets be fair now, Doug Axe has published several papers since 1999 which clearly have some relevance to evolution and Intelligent Design.

Axe DD, Dixon BW, Lu P. Stylus: a system for evolutionary experimentation based on a protein/proteome model with non-arbitrary functional constraints. PLoS One. 2008 Jun 4;3(6):e2246

Axe DD. Estimating the prevalence of protein sequences adopting functional enzyme folds. J Mol Biol. 2004 Aug 27;341(5):1295-315

Axe DD. Extreme functional sensitivity to conservative amino acid changes on enzyme exteriors. J Mol Biol. 2000 Aug 18;301(3):585-95

Axe DD, Foster NW, Fersht AR. An irregular beta-bulge common to a group of bacterial RNases is an important determinant of stability and function in barnase. J Mol Biol. 1999 Mar 12;286(5):1471-85

His more recent work is a bit strange, I'm still not sure that Han Chinese characters are really a particularly relevant model for protein evolution but his previous biochemistry papers seem like fairly good solid experimental work. The conclusions he draws from them do have implications for ID but to think that they form some sort of evidence would be to stretch them much further than the research will stand.

TTFN,

WK


This message is a reply to:
 Message 106 by Theodoric, posted 07-20-2009 1:21 PM Theodoric has not yet responded

    
Wounded King
Member (Idle past 2291 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 123 of 136 (548432)
02-27-2010 4:22 PM
Reply to: Message 122 by Feathertail
02-27-2010 3:37 PM


What does Information mean to you?
I may be unique in seeing the genome as equivalent to a computer program.

You aren't but that doesn't necessarily make it a genuine equivalence.

The problem with the 'information content of the genome' argument you are making is that by any actual usable metric of information, i.e. Shannon information, Kolmogorov complexity or Szostak's functional information, it clearly can be shown that mutation can add information to the genome and selection can lead to its preservation and accumulation.

The usual ID counterargument is based on the assumption that some arbitrary genetic sequence they have chosen is the maximal one for 'Genetic Information' and that any change to the sequence must therefore lead to a decrease. The problem with this is there is no evidence for such a platonic informationally maximised genome.

You seem to be just the latest person to be joining the ongoing list of ID supporters we try to pin down on exactly how they measure 'the information content of the genome'.

TTFN,

WK


This message is a reply to:
 Message 122 by Feathertail, posted 02-27-2010 3:37 PM Feathertail has not yet responded

    
Wounded King
Member (Idle past 2291 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 133 of 136 (623106)
07-08-2011 6:32 AM
Reply to: Message 131 by Chuck77
07-08-2011 4:49 AM


What does IC mean?
I know this wasn't addressed to me, but I've never let that stop me before.

Irreducible Complexity is an attribute of a system. The existence of such systems is put forward by advocates of Intelligent Design as evidence for the insufficiency of current evolutionary theory.

The problem is that there are several different definitions of irreducible complexity kicking around the ID debate, even from the same ID proponent.

Behe, 1996 writes:

By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.

This seems a fairly straightforward definition and if we take a 'part' to be a specific gene or protein we can probably find examples of such systems in living organisms.

Despite this most of the examples usually given (the eye, the bacterial flagellum and the blood clotting cascade) don't really stand up as IC by this definition and ID proponents often argue that such systems have an 'IC core' of proteins/parts which is what remains when all the non-essential parts have been removed form the putatively IC system.

However this doesn't really represent a problem for standard evolutionary models, there is no reason why a system can't evolve which relies on such a set of interconnected 'parts', there are several models based on exaptation and scaffolding which can account for them.

In response to this Behe 'refined' his definition ...

Behe, 2002 writes:

An irreducibly complex evolutionary pathway is one that contains one or more unselected steps (that is, one or more necessary-but-unselected mutations). The degree of irreducible complexity is the number of unselected steps in the pathway.

Clearly this is a completely different argument and requires a much greater depth of historical knowledge of the evolution of the system to be able to actually define any system as IC. Indeed it is hard to see how any ID proponent could confidently claim that a system was IC under this definition assuming it also has to satisfy the original definition.

If it doesn't have to satisfy the original definition as well then there are plenty of experimental examples of apparently unselected steps being required for the development of a functional system/trait, including any 2 step mutation in the classical antibiotic/phage resistance experiments using replicate plates. Indeed there is considerable weight to the argument that deleterious mutations can provide important intermediates to the evolution of a more beneficial state.

is there a better way they could present ID OR IC?

IC would be better presented if it had a clear and concise definition and some examples which actually matched the necessary criteria or at least an understandable way to discern if a system matches the criteria. At the moment IC is one of those things like increases in genetic information, IDists can't really define it but they will know it when they see it and they never see it in any of the examples they are provided.

TTFN,

WK


This message is a reply to:
 Message 131 by Chuck77, posted 07-08-2011 4:49 AM Chuck77 has not yet responded

    
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