I've both praised SEED magazine and tried to bury it [SEED and the Central Dogma of Molecular Biology - I Take Back My Praise]. This is one of those times when, unlike Mark Anthony, my main goal is to praise Caesar. Caesar in this case is PZ Myers who shows us month after month that there can be real science in SEED magazine.This month's column is about development in fruit flies. At least that's what it looks like on the surface. The take-home message is telegraphed in the title of the article and the subheading ...
Algorithmic IneleganceBravo PZ! Life isn't designed. It isn't designed by
Complexity in living things is a product of the lack of direction in the evolutionary processes, of the accumulation of fortuitous accidents, rather than the product of design.
I have always thought that randomness (the sources of those accidents) was a pretty elegant idea - you can get it to do all sorts of things: encrypt a message by making it look random; ordered patterns when compressed start to look random; remove the interference of moiré patterns with random selection; random sequences, if long enough, contain every conceivable pattern in an equitable distribution. Talking about equity, randomness is very even handed: that’s what makes ‘evolutionary diffusion’ in morphospace ‘isotropic’ – that is, having no preferred direction.
ReplyDeleteBut who needs ‘directed’ anisotropic diffusion when morphospace itself is not isotropic and homogeneous? Some structures are clearly ‘more equal’ than others and lock themselves in with a ‘winner takes’ all behavior. Evolutionary diffusion might be democratic but the ‘nonlinear’ structures it may chance upon are not!
Life isn't designed....it isn't designed by natural selection.
ReplyDeleteExcept, of course, that very often it is. Have you read Hochachka & Somero?
How the hell do you think that those "fortuitous accidents" actually accumulate? Really, this selection-bashing has gotten so tiresome that I quit.
Originally posted to Pharyngula...
ReplyDeleteI didn't read the column you referenced yet, buy I did find a previous column "A Profound Sense of Time"
I was surprised at how often you referred to "organization". I wonder if you truly understand the difference between "organization" and "complexity". You state in your latest article "Complexity in living things is a product of the lack of direction in the evolutionary processes, of the accumulation of fortuitous accidents, rather than the product of design." You seem to use these terms interchangeably. Unfortunately, there is a world of difference!
The reason I make this point is because complexity can be generated by non-random, accidental ocurrences, wheras organization cannot. Living systems are made up of structures and processes integrated in such a way that they not only support each other, but they contribute to the overall function of the living system. This type of organization, in which means are adapted to ends and multiple structures and processes perform multiple functions, all of which contribute to the overall functioning of the organism are unattainable by any kind of random process or chance occurrence. It requires insight and insight means intelligence. There's simply no way to get around that basic point.
Take a specific example, such as the eye. It is made up of many various structures and processes and all of these structures and processes are integrated in such a way so as to enable vision. Each structure and each process has its own specific function, which acts in support of the other functions and contributes to the overall function of the eye, to allow vision. In addition, this structure itself is integrated into the overall structure of the body and contributes to the maintenance of the living state.
It is my contention that the organization of these structures and processes and their assembly into a functional system required insight, and could not have been accomplished by random, accidental fortuitous occurrences. In order for your evolutionary view to prevail, you must somehow demonstrate that evolution has the power vested in it by you and you must demonstrate that random, non-directed processes such as mutation have the power to organize and assemble highly integrated systems in which means are adapted to ends. Until then, it's just a story,
OK then, who's going first?
ReplyDeleteSven Dimilo asks,
ReplyDeleteHow the hell do you think that those "fortuitous accidents" actually accumulate?
Many of them accumulate by random genetic drift. You haven't been paying attention, have you?
Really, this selection-bashing has gotten so tiresome that I quit.
Please don't go. I need some adaptationists here so I can keep up the selection-bashing.
Serendipity is vital, but only part of the picture. "Interesting" complexity requires multiple levels of indirection -- something that engineers can appreciate (especially software engineers - functions calling functions, etc...). The transformation of DNA into a functioning organism is an incredibly indirect process.
ReplyDelete"accidents" can accumulate by drift, sure...but if they're "fortuitous" doesn't that imply a benefit...i.e. selection?
ReplyDelete