Guys, thank you. I agree with Donal. That said, I have come to think that this sort of discussion is misdirected. Why? It takes place at a level of abstraction that misses too much of what is actually going on. The case of the big and small beetles with which this thread began is a thought experiment, constructed, as the authors themselves repeatedly warn their readers, to work out mathematically the implications of a few simple assumptions. In this case, we are asked to imagine just two types of beetles (large and small) and one form of competition for one resource (food) and to add two assumptions: (1) that if two beetles of the same size compete for the same food, each will get half, while of large and small beetles compete, the large beetle will get the lions share; and (2) that the large beetles make less efficient use of the food they consume. Then, numbers based on -- but not determined by -- these assumptions are assigned to four possible outcomes, where, given a pair of numbers {x, y}, the x represents the payoff for Beetle No. 1 and y represents the payoff for Beetle No. 2. Small beetle, small beetle= 5,5 Small beetle, large beetle=1, 8 Large beetle, small beetle=8,1 Large beetle, large beetle=3,3 Given this model, a population of small beetles invaded by large beetles turns out to be "evolutionarily unstable." The large beetles gradually drive out the small beetles. The result, however, is a large beetle population in which the efficiency of use of the food resource declines from 5 to 3. A, hah! the philosopher says, the model is too simple and the numbers assigned arbitrarily, who in their right mind would believe its conclusions. The scientist says, "No, duh" and proceeds in one or both of two possible directions: (a) construct a more complex model or (b) compare the model's predictions to data about beetles or other organisms. The latter is where the results become interesting. It turns out that, with a little tweaking of the numbers, the model, simple as it is, comes remarkably close to predicting the outcomes of all sorts of observed phenomena. Given two species, competing for a single critical resource, this "arms race" model of size competition seems to apply pretty well to all sorts of organisms and plants as well as animals. Is it the last word? Of course not. Improved models may account for the same or new data even better. But, hey, that's the way science works. Not by navel-gazing contemplation of whatever prejudices the philosopher wannabe starts with. John On Wed, Aug 18, 2010 at 6:37 AM, Donal McEvoy <donalmcevoyuk@xxxxxxxxxxx>wrote: > > --- On Wed, 18/8/10, Mike Geary <jejunejesuit.geary2@xxxxxxxxx> wrote: > > >MOI: Do you thinker-people actually argue about this? > > Some did, some still do. The status of Darwinism is not entirely > straightforward, especially as only specific Darwinian explanations are > testable whereas the framework that sets what a Darwinian 'explanation in > principle' is not. Darwinism is also beset by problems, though it has been > remarkably successful in solving some of them. > > >It seems to me patently obvious that I can't direct myself to alter my > DNA. > > But it isn't so obvious, a priori, that DNA (or whatever material codes for > offspring's characteristics) might not be influenced by environmental > conditions or 'experience': that having to stretch for the high-up fruit > influences my DNA to mutate in the direction of 'tallness', 'greater > stretchiness'. We gain muscles through exercise: why should we not gain > adaptive genetic changes through the exercises the environment demands we > perform? It isn't obvious, a priori, that the genetic code is particulate > and combines rather than intermingles. Even if we accept it is obvious that > one cannot consciously direct changes in our DNA, that would make it far > from intuitively obvious that such changes are directless - and only appear > to have direction because the successful adaptations are the ones that > survive. > > > We're here by accident and will disappear by accident. > > Not entirely by accident perhaps, depending what is meant by accident. But > the truth that we are not here as part of a divine plan, or necessary > progressive sequence, gives many vertigo - and they prefer to escape into > 'justificationist' philosophies, whether these be Intelligent Design or > inductivism - or the view that Darwinism simply represents a synthetic a > priori necessity or an 'analytic' truth. > > > There's no such thing as fittest -- except at the moment. > > Popper puts it more like this: even the ill-fitted may survive, at least > until they are eliminated. > > Donal > > > > > ------------------------------------------------------------------ > To change your Lit-Ideas settings (subscribe/unsub, vacation on/off, > digest on/off), visit www.andreas.com/faq-lit-ideas.html > -- John McCreery The Word Works, Ltd., Yokohama, JAPAN Tel. +81-45-314-9324 jlm@xxxxxxxxxxxx http://www.wordworks.jp/