On Models

I have seen a number of comments over the years disparaging models. Here are two models:

F=ma
PV=nRT

Did you know that, ultimately, all models are mathematical relations?

So here I’ve shown two models. Very simplified, but still models. Both wrong by the way. BUT both are very usefull because they are predictive. I’ve been told that all of mechanical engineering can be summarized as “F=ma and you can’t push on a rope, everything else can be derived”. THAT is the measure of a model. Can you use it to predict an outcome successfully?

Don’t disparage models. Generally, there is nothing wrong with models, even wrong models. Disparage instead the inability of a model to predict. THAT is the problem with the general circulation models. They are not particularly successfull at prediction.

HEY. Wait a minute! What’s wrong with F=ma? To understand that, google special relativity. As for PV=nRT, that is the “ideal” gas law. All gases deviate from this in extreme conditions. So. Both are, in an absolute sense, wrong. Extremely useful, but not exactly right, hence, strictly speaking, wrong.

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About John Eggert

A minerals processing engineer in Canada. A cynic by nature, but open to being convinced!
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