When does adaptationism stop being a useful research strategy and start being a silly exercise?
Dennett’s Strange Idea
Answer: pretty much all the time.
In Dennett’s book Darwin’s Dangerous Idea Dennett argued:
“[Darwinism] eats through just about every traditional concept, and leaves in its wake a revolutionized world-view, with most of the old landmarks still recognizable, but transformed in fundamental ways.”
But in my earlier blog posting Survival of the Sickest, Why We Need Diseases, I put forward reasons why Darwin’s “revolutionized world-view” perverts and twists reality. This “revolutionized world-view” goes against accepted conventions in medical science and Systems Biology.
In Survival of the Sickest, I listed several “features” which Darwinism sees as “functional” but which medical science sees as disease: sickle cell anemia, cystic fibrosis, diabetes, hemochromatosis, high cholesterol, early aging, favism, obesity, blindness, winglessness, etc. Sure these diseases “function” to increase reproductive success in certain contexts, but is that how we really want to go about defining function? Hence, I agree with Allen Orr’s essay that Dennett’s “revolutionized world-view” is in reality Dennett’s Strange Idea.
Because Darwinism sees everything in terms of reproductive advantage (aka fitness), it is limited and often misleading in attempts to identify and characterize working biological systems. We have various systems in biology, for example : the digestive system, the immune system, the respiratory system, the visual system, the reproductive system, etc. Did we need Darwinism to elucidate these systems? No. Do we need Darwinist story telling in the growing field of Systems Biology to elucidate future discovery of other biological systems? Probably not.
In practice, how do systems biologists persuade themselves that a system actually exists? Do they have to concoct some evolutionary narrative of how a system will lead to reproductive advantage? No.
So what is the accepted strategy for identifying and describing systems? Andreas Wagner in his book Robustness and Evolvability in Living Systems (Princeton Studies in Complexity) describes how in practice the fitness-based, Darwinist world view is supplanted in favor of a more effective methodology:
However, fitness is hard to define rigorously and even more difficult to measure….An examination of fitness and its robustness alone would thus not yield much insight into the opening questions. Instead, it is necessary to analyze, on all levels of organization, the systems that constitute an organism, and that sustain its life. I define such systems loosely as assemblies of parts that carry out well-defined biological functions.
but Wagner’s definition of “system” sounds hauntingly similar to Michael Behe’s definition of Irreducible Complexity:
A single system composed of several well-matched, interacting parts that contribute to the basic function of the system
Wagner is not alone in pointing out the problem of defining and measuring “fitness”. In addition to Wagner, Allen Orr highlights the problems of using fitness to define functional designs.
Dennett is fond of speaking of selection as leading organisms through “Design Space”: Selection “lifts” organisms along “ramps” of good Design. The first is that natural selection cares about Design. In reality, selection “sees” only brute birth, death, and reproduction, and knows nothing of Design. Selection — sheer, cold demographics — is just as happy to lay waste to the kind of Design we associate with engineering as to build it. Consider the eyes of cave organisms who live in total darkness. If eyes are expensive to make, selection can wreck their exquisite engineering just as surely as it built it. An optic nerve with little or no eye is most assuredly not the sort of design one expects on an engineer’s blueprint, but we find it in Gammarus minus. Whether or not this kind of evolution is common, it betrays the fundamental error in thinking of selection as trading in the currency of Design.
Second, hazy imagery of selection lifting organisms along Design ramps makes it hard to see that selection sometimes moves individual traits down ramps. But this surely occurs.
It’s not that we can’t say that such and such a trait is reproductively fit in such and such a context. The problem is we can’t universally relate fitness to function, and Darwinism relies on universally tying fitness to function.
Orr relates the problem by the example of Gammarus minus. In one context the ability to see is “fit” yet in another it is “unfit”. But how can such a fluid, unstable, incoherent definition of fitness be useful for identifying and characterizing function? Answer: it can’t.
In light of this we might ask, if a theory like Darwinism can’t define or measure it’s most fundamental quantity in relation to its major claim (namely evolution of function), should Darwinism be given the status of science, much less hailed as a cornerstone of science? I think not.
So if Darwinism is too incoherent a world view for defining function and identifying systems, what is a better way for identifying functions or systems? The better way is via pattern recognition.
For example, we might find a car in ravine. How do we know it ‘s function? Being in a ravine, the car is clearly not in a context where it can demonstrate its function, but we recognize it is a car and we can recognize its function because we have in our minds templates and patterns for what cars look like. Even if the car is broken, we can still recognize function in its broken parts through pattern recognition.
Likewise we use patterns to recognize copiers, computers, software, operating systems, control systems, transportation systems, communication systems, energy conversion systems, navigation systems, memory systems, sensory systems, etc. But all these systems are found in biology. How do we recognize these systems? Not through the “silly exercise” of adaptationist stories, but through our study and knowledge of patterns in human intelligent activities.
Thus, the study of patterns is superior to Dennett’s Strange Idea when we attempt to identify and characterize systems and function. This idea also accords well with what someone else once said:
Intelligent Design is the study of patterns that signify intelligence.
1. Kevin Anderson demonstrated that a large fraction of anti-biotic resistance occurs through loss of function in bacteria. See: Is Bacterial Resistance to Antibiotics an Appropriate Example of Evolutionary Change?. This further adds support to Orr’s claims.
2. Sanford in the book Genetic Entropy relates the problem of selection interference where on favorable trait destroys another favorable trait. For example a stupid but fast individual might be differentially favored over a not-so- fast but intelligent individual. Thus the favorable trait of intelligence is eliminated in a strongly selective environment, when in reality both traits (speed and intelligence) are favorable. This also supports Orr’s claim.
3. In addition to Wagner and Orr, Lewontin describes in more technical detail the problem of defining and measuring fitness as it relates to characterizing systems and functions in Santa Fe Bulletin 2003.
Unfortunately the determination of fitness is a great deal more complicated than is usually supposed. It is easy to say that fitness of a type is its “relative probability of survival and reproduction” but turning that phrase into a coherent measure that can do work in evolutionary explanation is not so easy.
First, it is obvious that the fitness of a type depends on the environment in which the organism lives. But the environment is not independent of the organism. Organisms, by their biology, determine what aspects of the external world are relevant to them and constantly change their environment by their life activities. That means that as a collection of organisms evolves, their environment evolves with them.
The problem is that it is not entirely clear what fitness is. Darwin took the metaphorical sense of fitness literally. The natural properties of different types resulted in their differential “fit” into the environment in which they lived. The better the fit to the environment the more likely they were to survive and the greater their rate of reproduction. This differential rate of reproduction would then result in a change of abundance of the different types.
In modern evolutionary theory, however, “fitness” is no longer a characterization of the relation of the organism to the environment that leads to reproductive consequences, but is meant to be a quantitative expression of the differential reproductive schedules themselves. Darwin’s sense of fit has been completely bypassed.
How, then, are we to assign relative fitnesses of types based solely on their properties of reproduction? But if we cannot do that, what does it mean to say that a type with one set of natural properties is more reproductively fit than another? This problem has led some theorists to equate fitness with outcome. If a type increases in a population then it is, by
definition, more fit. But this suffers from two difficulties. First, it does not distinguish random changes in frequencies in finite populations from changes that are a consequence of different biological properties. Finally, it destroys any use of differential fitness as an explanation of change. It simply affirms that types change in frequency. But we already knew that.
Lewontin said: “It is easy to say that fitness of a type is its ‘relative probability of survival and reproduction’ but turning that phrase into a coherent measure that can do work in evolutionary explanation is not so easy.” How about downright impossible, right up there with finding square circles!
4. It should be worth mentioning, there isn’t much selection operating in the wild on most of the genome. This is well known from the works of Nei, Kimura, Jukes, King, Pagels. So Dennett’s strange idea is a moot point since selection isn’t a major force in biology anyway.
5. HT: Bradford at TelicThoughts who inspired this thread: De Facto Intelligent Design in Biology