"John Edser" <[email hidden]> wrote in message news:<[email hidden]>...
Quoted message said:Neo Darwinists do _not_ restrict their fitness count to only fertile forms reproduced, but
Darwinists, do for very obvious reasons. A form that is born sterile can only have a zero
independent fitness until it becomes fertile. For a form to be able to donate fitness, it must
have an independent fitness to donate. This is only possible for a form that is born sterile (all
forms, even single cells are born sterile) but becomes fertile. Only when a form matures to
fertile adulthood, and then becomes sterile rather than remaining fertile is organism fitness
altruism (OFA) proven.
I believe that John is confusing two different usages of the word fitness here.
One is the fitness of results achieved. It is (in principle) a measurable quantity. Everyone,
Darwinists and neo-Darwinists alike, wants it to represent some kind of long-term success, but,
since it is supposed to be measurable, is forced to limit the period of measurement to something
like a single generation. In a species without polymorphism that follows a predictable life cycle,
you can measure fitness by choosing ANY point in the life cycle, observing for about a generation,
and then counting the number of children that have achieved the SAME point in the life cycle. That
is, you can measure from conception to conception, from birth to birth, or from fertility to
fertility. The results are roughly the same, regardless of which definition you choose. However,
there are some technical advantages and disadvantages to consider in making this choice.
One factor in favor of the fertility-to-fertility definition of fitness is that this stage in the
life cycle is probably easier to count than some other stages. Another advantage is that a larger
fraction of the organisms will have a non-zero fitness. (The fitness of an oak tree is extremely
variable if measured from seed to seed - it is less variable if measured from adult tree to adult
tree). On the other hand, the birth-to-birth definition has the advantage (particularly for
organisms without much parental care) that it puts the responsibility for maximizing fitness in the
right place - on the genome of the child. (The fitness of a spawning salmon, if measured fertility-to-
fertility, would be the number of children that survive to spawn. But, if measured birth-to-birth,
each minnow is seen as responsible for its own fate.)
And that brings us to the second usage of the word fitness - expected fitness. Here, we are trying
to predict, based on the genotype of the organism, just what the average measured fitness for
organisms of that genotype will be. It should be clear that an explanation of how genes affect the
fitness of a minnow should probably be talking about the genes of the minnow, rather than the
genes of the parent. On the other hand, in a species with parental care - such as [censored] sapiens -
the survival of a child may well be due more to the genes of the parents than to the genes of the
child itself.
What about sterile forms in eusocial insects? What about forms like the worker castes in Melopena
that have some fertility, but less fertility than queens? Now, we no longer have a situation in
which there is a single simple life cycle. The definition of measured fitness becomes more
problematic. A reasonable solution to the problem makes use of Fisher's notion of "reproductive
value". A newly fertile queen has one value, a newly semi-fertile worker another, a newly fertile
drone has yet a third number for reproductive value, and a fully sterile form has zero reproductive
value. Immature forms can also be given a reproductive value - it is the value of the mature form
discounted to take into account the probablility of death before maturity. Now, given this
conceptual machinery from Fisher, we can define a measurable fitness for any organism. It is the sum
of the reproductive values of all offspring. Neo-Darwinists, if they are sane, will not count
sterile offspring in their counts. Or rather, they will count them, multiplying each one by a
reproductive value of zero. I am talking here about BASIC fitness. John seems to believe that neo-
Darwinists are insane - that is wishful thinking on his part. They are not stupid enough to count
sterile forms as if they were fertile.
What about INCLUSIVE fitness? That is more complicated. In social situations, the genotype of a form
has an effect not only on its own survival, but also on the survival of relatives and complete
strangers. Hamilton suggests defining a new quantity called inclusive fitness in which each genome
takes credit for ALL of the effects it produces in producing copies of itself. That is, if I help a
full sibling, I should get half the credit for the extra offspring that my sibling produces. But, if
my sibling helps me, he gets half credit for my extra offspring. That is the definition of inclusive
fitness. It is basic fitness, plus a little bit for helping relatives, minus a little bit for being
helped by relatives.
Fisher, ignoring social issues, proved that natural selection acts to maximize basic fitness.
Hamilton [1964] proved that, when social issues are taken into account, natural selection maximizes
inclusive fitness, rather than basic fitness. The trouble is that, whereas basic fitness is easy to
measure, inclusive fitness is next to impossible to measure. To measure it, you have to decide how
much fitness credit to transfer from the recipient of altruism to the donor. That involves much more
understanding of the natural history of the organism than is currently possible. (Fisher's
reproductive value required some understanding of natural history - Hamilton requires much more.)
It is important to realize that you can define an inclusive fitness given any of the competing
definitions of basic fitness. That is, you can have an inclusive fertility-to-fertility fitness. In
fact, that is what Hamilton proposed in 1964. Later, recognizing that parental care can be thought
of as a kind of altruism to relatives, there was a transition to using birth-to-birth or conception-to-
conception definitions of basic fitness.
The one thing that I believe is causing the most confusion for John is that sterile forms are
treated as real players in the natural selection game. They have no basic fitness, but they may have
an inclusive fitness. They act as programmed by their genes, and their actions have an effect on
gene survival. It is possible to define an inclusive reproductive value, so that these forms no
longer count as nothings in their parents fitness accounting. But, under no circumstances can they
be thought of as counting as much as mature reproductives in the fitness counts of their parents.
Quoted message said:In Neo Darwinism one unit of selection is just one gene replicated into however, just the next
_organism_ generation (no matter if that organism is fertile or sterile!) and not the next _gene_
generation. This means that Neo Darwinists do _not_ make a logically self consistent unit of
selection count so their results remain in very serious error. Such a major error disallows
Hamiltonian OFA to be caused by supposed selfish geneism. For OFA to be just a logical
possibility, gene fitness counts must include all mitotic replications of that gene because the
fitness of a parental gene is the total number of gene replications by mitosis and meiosis over a
defined period.
I can't believe that John is serious in this criticism. It would be insane for any evolutionary
theorist to count all mitotic divisions as generations simply because EVERYONE - Darwinist and neo-
Darwinist alike knows that it is organisms that die and reproduce. Everyone is also in agreement
that the thing that changes over time is gene frequencies.
Is John suggesting that Hamilton's theory would be improved by counting mitoses, or is John simply
trying to discredit Hamilton by reductio ad absurdum? No one except John, as far as I can tell,
thinks that a failure to count mitoses is an internal contradiction in neo-Darwinism.
Quoted message said:For Darwinists one unit of selection is one fertile organism reproduced. From a "genes eye view"
this is one gene replicated into the next _fertile_ organism population. Here counting genes is
just a useful way to count fertile organisms. [snip]
Quoted message said:Neo Darwinists misuse over simplified models _consistently_ and simply refuse to even consider any
possibility of model misuse. Indeed, nobody agrees on what the difference is between a model, a
hypothesis and a theory. GH suggests all models are testable but Prof. Felsenstein suggests no
models are testable. GH wishes the "tyranny of refutation" could be banished from evolutionary
theory(!). Most Neo Darwinians talk as if Popper and Godel did not even exist. In short, the
epistemology of Neo Darwinism is, chaotic. It is impossible to start a discussion on POSSIBLE
MODEL MISUSE because it appears to be simultaneously, gene and ego, centric. However, I will try
and will always keep on trying, to raise a rational, unbiased discussion of this critical topic.
Misuse here was:
1) The massive oversimplification of a fitness count to include infertile forms.
I suggest that the oversimplification is in John's understanding of the theory, rather than in the
theory itself. The full neo-Darwinist account of fitness addresses all of John's complaints.
Quoted message said:2) The ERROR of a non self consistent unit of selection count.
I am not sure exactly what this means, but let me point out that economists refer to households as
"units of economic decision making". In using this terminology, they are not making the assumption
that rich and poor households purchase the same amount of goods.
Quoted message said:3) Reducing all variables to just one. At all times a minimum of TWO variables must be included
otherwise a variable becomes a defacto constant.
I am not sure I understand this one. No doubt clarification, or at least repetition, will be
forthcoming.
