Hi Christy,

I think that your distinction between the art-practice and the artwork is important, and deserves attention.  But we should recognize that in some cases of art-practice, the act of production may not be different from the product.  Music performance is both practice and product.  So the distinction you make is troublesome (for me) only in the case of what we might call the productive arts -- arts where the practice yields a product distinct from itself.  Music composition, painting, writing are example.

In my original post, I didn't say what the function of art was.  One way your distinction is important is that it forces me to take a certain line on this.  Here's how.

First, a heritable trait T has function F if T's performance of F allows T to be maintained in the population by natural selection.  (Notice this is not an origin statement, but a statement about what feature of T is causally responsible for the original and continued existence of T.)  The art-function thesis is that art-practice is based on (genetically) heritable skills, and that it is maintained in the population at least partially because it creates products of a certain sort -- call this sort of thing B.

Conceding the art-function thesis for the sake of the argument, I think we can go straight to a version of your premise 4:

4M.  A function of art-practice is the production of B-things.

Now, as you point out, 4M doesn't tell us much about the function of art-products.   For B-things may be valued for something else entirely.  The function of carpentry is the production of furniture -- but this doesn't tell us what the function of furniture is.  This is your point, I think, and it's a good one.

The irony is, however, that when you apply your distinction to art, it creates a puzzle.  Artworks are special in that they have no purpose or function other than themselves.  But this raises the question: how could it have been useful (in evolutionary terms) to produce things that do not contribute to physical well-being and reproduction?  Or to put it differently: how can anything other than a material advantage contribute to evolutionary fitness?

So far this is a reasonable puzzle, I think.  It runs parallel to the question of how altruism can have evolved -- since apparently altruism too fails to contribute to the physical well-being or reproduction of the practitioner.  Some answers to the altruism question are "arm-chair yarn spinning", as you say -- but non-empirical theorists have laid out what would have to be true if altruism did evolve.  And this is not mere yarn-spinning.

The working-heart of Dutton's thesis is that art-producers gain the evolutionary advantages of their practice only if the things they produce shows the mark of their authorship.  Only by producing things that display their authorship can they gain a material or reproductive advantage.  (Again, let's not go into this too deeply, since this would take us off our main track.)  This gives us something of the form:

7M.  A function of artworks is to display marks of the producer.

From 7M, you can derive some art-critical norms by the argument you provide.