Fitness: Hueristic or Fundamental to Biology?

Look folks, it appears you all are getting wrapped around the axle on what is essentially a very trivial point. Fitness is simply a metric that was developed by scientists (probably pop geneticists, since they're the ones mostly concerned with this kind of thing) in an attempt to put a quantitative measurement on what is an inherently qualitative comparison - the relative adaptiveness of a particular genotype in its current environment. As such, it is no more recursive than any other metric - say using a meter-stick to measure the length of a wall. In addition, as anyone who's had to develop a performance monitoring plan for a project can atttest, this is probably one of the most difficult excercises to accomplish. The worst argument I've had with my current contractor developed over establishing performance measures for our project: how do you measure the impact of a nature center on local attitudes and actions? The metrics have to be both realistic (i.e., attainable), and measureable. Don't ask me why people demand numbers for this kind of thing, but there it is. Fitness calculations are no different.You can argue until the next ice age over whether or not the currently accepted metric is valid. Those who find it useful (I don't particularly - I don't deal with those kinds of questions) will continue to use it and/or seek for a better one. Those who don't find it useful will continue to argue against it.

"Have you stopped beating your wife yet?"It is not "necessary", but it can be useful for understanding some questions under the rubric of natural selection. The current definition of fitness refers to a metric measuring the outcome of NS. The unit of time used is one generation. Any other questions?

I have no intention of re-hashing the gene/individual debate here. So two points only:1. I never said - nor do I believe - that the fitness measure outlined here and in the previous thread is in any way "arbitrary". Or, at least, it is no more arbitrary than any other metric. Is a meter arbitrary? I suppose in a very trivial sense it might be so considered. After all, it is simply a standardized unit of distance whose length has been developed and adopted by concensus among those who need to measure such things. There have been other metrics of distance in the past - some of which are still in use today. I don't see "fitness" as being any different, although it is a bit fuzzier around the edges, and is still in the process of evolving. For those who need to measure such things, the concept is a practical one - just like a meter.2. The use of fitness in the previous thread was not intended as some kind of "acid test" of genecentrism. It was, even if I didn't perhaps express myself as well as I could have, intended as an example of a type of question genecentrism doesn't appear to address well. Although you attempted to address the issue by postulating a different metric - number of times an allele replicates in a particular time frame (which is probably sufficient if what you're trying to measure is simply the relative fitness of a given allele, which undoubtedly has utility in some contexts) - I would still contend that this doesn't help us to understand higher-level outcomes such as genotype/phenotype contribution, etc, which is what fitness as defined is trying to do.Feel free to continue misrepresenting my position on this. Some day perhaps you'll explain why you've taken this approach to me on this subject.