Re: Hosts vs. Instances

Tim Rhodes (
Thu, 24 Sep 1998 12:25:37 -0700

From: "Tim Rhodes" <>
To: <>
Subject: Re: Hosts vs. Instances
Date: Thu, 24 Sep 1998 12:25:37 -0700

Aaron wrote:

>Time t is not an integer in those equations. Predictions are made using the
>equations or computer models. All predictions of a host population at time
>t = T being within a specified interval are contingent upon parameters
>remaining within corresponding intervals, unless a periodic re-measurement
>scheme is incorporated.

Yes, as you write in your paper:

"In general, propagation parameters can be measured over the duration of the
time interval being modeled, as can the initial host populations of the
memes under study. If the propagation parameters remain in some specified
interval, then the final host population plus or minus a calculable error
margin should be measured at the end of that interval. A host population
measurement outside those error margins would then falsify the model being
used for the specific memes under study."

So, if I understand you correctly, this model is only applicable to cases
where the propagation parameters (your K, B and Y terms) remain constant (or
close to it) and not for all memes generally.

Is this a correct reading of what you've said?

>Why are you talking about t+1?

Sorry, I seem to have made the mistake of assuming that an accurate model
memetic activity would be one in which the model had predictive power
applicable to real world events, not just computer simulations. One that
makes predictions about future events which can then be falisified by the

>You cannot even assume from the model that
>it will be applied for a whole year, nor can you assume that it will be
>applied for less than a year.

I have made no such assumption. By "t+1" I simply meant "a unit of time in
the future." I was not implying how long that unit should be. I assumed
you were aware of the convention of f(t) and f'(t) = f(t+1).

>The model is far easier to use in phenomena
>where propagation parameters are stable enough that they do not need
>frequent re-measurement. The same thing with epidemiological models,
>population genetic models, and so on.

Yes, but we are not modelling populations or disease. We are modeling
memes, and as such our models must be able to apply to memes.

>>Is all this necessary? At this point, doesn't Occam's Razor demand that
>>let loose of the ineffective hosts-to-conversion-rate assumption at this
>>and approach the problem from an instance-of-meme-to-conversion-rate
>>viewpoint instead?
>The last question looks utterly confused, as there is a one to one
>correspondence between host of a meme and instances of that meme.

This is not the case, although I see the confusion. By "instances of a
meme" I was refering to instances of _exposure_ to the physical
manifesations of a meme (meme-seeds, proxi-memes, artifacts, husks, whatever
term you wish to use). In your paper you note that, "The B's, and Y's
likewise do not reflect how many (times) a message was voiced from hosts to
a non-host before that non-host converted." By "instances of a meme" I
meant to refer to your "messages being voiced."

Sorry, I forgot that we are not using the term "meme" in the same way.

But, I think you will agree, there is NO one-to-one correspondence between
the number of hosts of a meme and the number of instances of _exposure to_
that meme. And that was my point.

For in your paper you state:

" The overall theory would conceivably be falsified by refuting its premises
or the logic and mathematics based on those premises."

If a) adoption rates are known to correspond to instances of exposure to a
meme (as shown by diffusion studies), and
b) there is no one to one correspondence between hosts of a meme and
instances of exposure to a meme, then
c) any discussion of adoption rates linked to number of hosts in a
population rather than instances of exposure must be logically incorrect.

Is that somewhat clearer now?

>If you have an idea for a better system of differential equations, then why
>don't you write it up and submit it for publication?

How did I know you were going to say that?!? (I must be psychic!)

Yes, Aaron, I had written up a system of equations over a year and a half
ago. (I have shared them with Gatherer, Brodie, and others for feedback.)
They were very similar to yours, and led me down that same path you have
taken. It soon became apparent to me that the most crucial term in all the
equations was the term which governed an individuals likelyhood to adopt a
meme from the environment into his internal meme-set. (This term was
labeled R-sub-x in my equations--the x representing the meme in question.)

Because I ran up against a wall where the importance of understanding and
expanding this term became necessary in order to continue with any of the
equations, I was forced to set the problem aside and seek more information
on controlling factors which govern the choice to adopt. I believe
diffusion studies shed some light into this area, but have not completed my
research into them enough as of yet, to be sure. Ideally, I would prefer to
have some emperical data to work from in this regard. The diffusion
research seems the closest to that I have come across thus far. (Although I
am open to suggestions!)

And to be completely honest with you, Aaron, as an unpublished former
college drop-out with an interest in memetics, the prospect of trying to get
my work excepted in a forum such as this, after witnessing all the academic
prejudices displayed by those such as you, is truly less than inspiring to
me at the moment.

-Tim Rhodes

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