> Carrol Cox wrote:
>
> > Then he is either using "model" as a mere (and not too good) synony
> > for "abstraction" or he is wrong. Models as used in economics havd
> > no place in Marx.
>
> Some assumptions in those models have no place in Marx, because Marx made
> different assumptions.
>
> Anyone attempting to make sense of capitalism will single out some factors
> as more important than others and draw relationships between whatever they
> find relevant. They have a simplified sketch with interrelated parts. For
> the sake of rigor and clarity, they render the sketch in some specialized
> language. Call the final product whatever you like, but they have built a
> model.
>
> As for all that math, Barkley Rosser said:
>
> I would also like to point out that having equations does not necessarily
> equal "math" and not having equations does not necessarily mean "not math."
> Math involves the ideas and their nature.
>
> Thus, John Chipman has argued (sorry, no cite) that John Stuart Mill
> invented nonlinear programming in his chapter on exchange rates in one of
> the later editions of his Principles of Political Economy. He did so
> strictly using words in a verbal description. But, there is no question, he
> laid out a rigorous (and correct) mathematical argument. Also, while she
> generally said bad things about using math(s), Joan Robinson's growth theory
> models were generally mathematically rigorous, even if usually described
> strictly in words, although she would sometimes resort to figures or graphs,
> which is getting a bit more overtly mathy.
>
> OTOH, there is a lot of fake or lousy math out there in econ that is not
> really math, that is really obfuscation and sometimes even wrong, irrelevant
> to what it is supposedly modeling or explaining, and so and so forth. There
> are equations, but the variables in them are meaningless, and there is no
> empirical content. They may even be made to look fancier and more
> complicated than they are with, unnecessary changes in variables, and so
> forth. Such things are not really math, even though they may look like it
> (and I am especially aware of this today, as I just finished writing a
> negative referee report on a paper of exactly this sort, with incoherent
> variables and even outright incorrect math).
>
> <
> http://rodrik.typepad.com/dani_rodriks_weblog/2007/09/more-on-math-an/comments/page/1/#comments
> >
>
> Shane
>
> ___________________________________
> http://mailman.lbo-talk.org/mailman/listinfo/lbo-talk
>
"I also think math has tremendous utility and power in clarifying and making accurate a theory (like Robert Feinman, I am a physicist). But one problem I had when reading economic theory papers is that there is a tremendous amount of effort spent on making their mathematical models *rigorous*, i.e in proving them in a mathematically strong fashion (this is true even of the most famous economic theorists, like Lucas). It makes little sense to me to do this, because the models themselves are so imperfect, and often inconsistent with data. Would it not be more reasonable to spend this effort on fixing inconsistencies between the models and empirical data, rather than proving their mathematical exactness?I see very in my profession spend their time proving their models rigorously."
Word for word what I've always thought...
Its long been recognised that mathematical theory, due to its very nature, tends to become a language operating without reference to reality. I remember the psychoanalyst Jacques Lacan went as far as to compare maths to chronic psychotic variants of mental illness, such as paranoid schizophrenia, insofar as both construct their own reality without reference to externalises. They both do this in a very specific way; they begin with some attempt to impose their framework onto some piece of empirical data; then they move onto building a bigger "model", taking progressively more and more "assumption" on board; finally they review the data with reference to the newly constructed "model" and purge any elements which don't fit. I think this comparison can be seen as unimportant when it comes to physics - but huge questions have to be raised when the techniques are being used to study and manage human behaviour, not merely from the point of view of validity, but also from that of ethics.
Its interesting that as fewer and fewer economists have any decent philosophical training - most of the originals were actually philosophers, or at least had a relatively decent grasp of epistemology - they tend to turn to maths to ground their theories. I've always seen a sort of nervousness here. Economics involves a lot of guesswork and many economists, in their striving for certitude and self-assertive scientificity, are more than happy to apply a methodology which could aptly be called "thinking with mirrors".
In saying all of this I've heard that chaos theory is showing some promise. Probably because instead of concerning itself with construction, it focuses on patterning. I'd love to see a decent reading of Marx through this framework. After all Marx could be said to be the first economist to attempt to deal with chaos through a methodology designed to bring out underlying tendencies through the study of internal contradictions.