Re: [OPE] Models and Marx

On 2011-02-11 00:40, Paul Cockshott wrote:
> The difference between the theory and the model is that the theory
> needs to be materialised and activated as a physical model before
> any predictions emerge.
>
> A theory is more abstract than a model, it tells you how to go about
> constructing a model, but until you have built the model and activated
> it you get no predictions out. This was harder to see in the past since
> the computations required to model the mechanics of the solar system
> according to Newtons laws were done by people using papers and pencils
> so the model in the sense of the computing system that produced the
> results, was distributed over the notebooks, the clerks who did the menial
> calculations and the directors like Laplace who developed the high level
> equations.
>
> A model now can be physically localised in an appropriately configured
> universal computer - and we at times abstract from the computer itself
> and say that the software package, independent of the hardware, is
> the model. But such a model is still something concrete, with a material
> existence and more importantly, a specific parametrisation.
>
> The general theory of celestial mechanics is not a model, but part of
> the means of production of models. The theory can be used to produce
> a multiplicity of models -- of different planetary systems, of galactic dynamics,
> etc.
>
> A model may be built in accordance with a theory, and if the theory allows a large
> number of models to be built, all of which models turn out to have a good predictive
> ability we say that the theory is a law.

Paul, I agree with what you wrote, especially about the 'materiality' of
predictors. The meaning of words like 'theory' and 'model' are in this
context of course somewhat elusive. By 'model' above you mean a concrete
empirical predictor. In my original post I meant to say that theories
'model' (as a verb) causal mechanisms and can be used to produce a
specific models (as instances) of physical systems where those
mechanisms are active. E.g. Newton's laws model certain causal
mechanisms of the universe and can be used to generate a predictive
model of the trajectory of celestial bodies.

Hence we can also say that the theory of phlogiston modeled the causal
mechanisms involved in combustion but did so poorly based on the
criteria by which we judge or rank competing theories: empirical
accuracy, logical consistency, generality and simplicity.

//Dave Z
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Received on Sat Feb 12 07:30:01 2011