RE: Terminology and Quantification

Aaron Lynch (
Thu, 22 Jul 1999 20:13:39 -0500

Message-Id: <>
Date: Thu, 22 Jul 1999 20:13:39 -0500
From: Aaron Lynch <>
Subject: RE: Terminology and Quantification
In-Reply-To: <002301bed280$ae37ec60$0d9e8cd4@paul>

At 09:22 AM 7/20/99 +0200, Paul Marsden wrote:
>David asked a simple, but critical question in Science that deserves a
>straight and clear answer.
>How do you define memetic fitness? Answers please.

A more considered definition (given in replacement to my previous one) is
as follows [switching to N1'(t) = dN1(t)/dt and N2'(t) = dN2(t)/dt notation]:

Fitness(meme1) = 1 + N1'(t)/N1(t)

Fitness(meme2) = 1 + N2'(t)/N2(t)

These are not normalized or relative fitnesses. But David Sloan Wilson did
not specify absolute, relative, or normalized fitness, or ones based on
discrete or continuous models. Besides, it is not at all important in
determining non-tautology. Giving equations for meme prevalence as a
function of time and propagation parameters is sufficient to avoid
"tautology" whether the word "fitness" is used or not. Merely giving
definitions of fitnesses as above without providing equations to solve for
N1'(t), N1(t), N2'(t) and N2(t) is not sufficient to avoid potential
"tautology" charges.

To avoid confusion, and minimize offense to geneticists (based on
traditions), I will probably refrain from calling my ideas of matrices and
vector functions "fitnesses." Instead, I will most likely label them
otherwise, perhaps as "propagative profile vectors" or "propagative profile
matrices." Note that all of my listserver discussion of the use of such
terminology was and currently remains tentative. As my paper did not depend
upon having any quantity defined as "fitness" in modeling meme prevalence,
I am only now considering how to define the term "fitness" in relation to
my mathematical model. I do try to pay attention to the effectiveness in
communication when considering terminology.

--Aaron Lynch

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