RE: JASSS Critical Review of Thought Contagion

Aaron Lynch (
Fri, 30 Apr 1999 10:55:58 -0500

Message-Id: <>
Date: Fri, 30 Apr 1999 10:55:58 -0500
From: Aaron Lynch <>
Subject: RE: JASSS Critical Review of Thought Contagion
In-Reply-To: <2CDFE2C8F598D21197C800C04F911B20224BC4@DELTA.newhouse.akzo

At 09:57 AM 4/30/99 +0200, Gatherer, D. (Derek) wrote:
>Anyone who knows enough about mathematics in the sciences
>Well actually I have 4 published papers in mathematical genetics and 1 in
>press, but I'll let that typically Lynchian comment pass..........
>Anyone who knows enough about mathematics in the sciences knows that
>equations do not need to be based on prior work in a different field. The
>equations were freshly developed, and were not adaptations of
>epidemiological equations.
>That's a very strange comment Aaron, you make it sound like you are working
>in an intellectual vacuum. When Cavalli-Sforza and Feldman presented their
>treatment of horizontal transmission back in 1981, they were quite happy to
>acknowledge their debt to mathematical epidemiology going back several
>decades. You, as a mathematician, must know what are the intellectual
>sources of your work. If your equations look like those previously
>developed by epidemiologists, then they are epidemiological equations or
>derivatives thereof.
>For instance in what follows I am quite happy to admit that I draw on
>Fisher's work from the 1930s, and all the textbnook versions since then. I
>would not be so presumptuous, or divorced from reality, as to claim that it
>is 'freshly developed'.

When I say "freshly developed," I do not claim any "intellectual vacuum" as
your distortional message suggests. But perhaps I should have cited Newton,
Leibnitz, and a variety of other mathematicians, along with the writers of
differential equation text books. I don't see this happening in other
science papers that use differential equations, though.

Now, you refer to mathematical epidemiology going back only several
decades. That means there must have been one or more freshly developed
works in mathematical epidemiology that did not derive from prior works in
mathematical epidemiology. Are you saying, in effect, that it is fine for
early mathematical epidemiologists to be "presumptuous, or divorced from
reality" (i.e., original) but not for early mathematical memeticists? If
so, this raises doubts as to how much respect you really give memetics as a

>You claim that:
>"As the taboo [ie. against homosexuality] becomes extremely
>widespread, most homosexuals live heterosexual lives, leading them to
>reproduce any genes involved. As the genes gain prevalence, the rate of
>taboo dropout increases."
>This won't happen. Even if there is no selection pressure against a 'gene
>for homosexuality' (let's make the standard sociobiological assumption that
>there is such a thing), then it will not 'gain prevalence'. In fact it is
>perfectly possible that it might go extinct.
>Imagine a population in which there is a gene for homosexuality S1 with
>frequency p. The corresponding gene for heterosexuality S2 therefore has
>frequency 1-p.
>Let's assume that there is a net mutation rate, u, to homosexuality
>[mutation rates occur in both directions, but net mutation rates, for
>obvious reasons are always towards the least prevalent allele], then the
>rate of increase of S1 in time, t, is:

No, I will not assume a rate of mutations to homosexuality, as this is not
the basis of my argument in _Thought Contagion_. My hypothesis is not based
on mutation rates, but rather, on the taboo's ability to dramatically
increase reproduction rates for those with predominantly homosexual
phenotypes. Take some genetic population segment that has a low
reproduction rate, give them a taboo that raises their reproduction rate to
perhaps mainstream levels, and their genes should start proliferating at a
rate much higher than that dictated by mutation alone. The fact that you
are trying to impute a mutation-based argument to me does not suggest that
we are yet ready to have a productive discussion. Besides, further
development and testing of my hypothesis is better suited to treatment in a
full-lenth paper.

--Aaron Lynch

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