I agree, universals can't exist because they are all human constructs. Although mathematical language such as Calculus and the laws of physics come pretty close, do they define or simply decribe the universe? This reminds me of Saussure's work on the arbitrary relationship between sign and signifier. For example; there is no reason why the letters A-P-P-L-E conjure the image of a small green/red fruit. Indeed, in french it is pomme and furthermore, no two apples are the exactly the same. I would say this was evidence of 'rational operations characteristic of certain brain structures' in the same way that calculus et al seeks to rationalise the universe.
Yes, much as cartographers impose a grid of longitude and latitude lines on a chaotic topography in order to make sense of it.
But on the other hand, sometimes such "constructs" are not merely imposed on the universe but seem to inhere to it. Take for example the trend of prediscovery in physics. How did Gell-Mann know that quarks existed? Only because the math said so. This discovery prompted observations that bore it out in fact. It is not that an artificial, mathematical order was invented to simplify observations that were in fact irreducibly complex, as in cartography. Instead, the mathematical order predicted the observations. Thus, although this order is utterly abstract and intangible, it is not just an artifact of our peculiar physiology. Indeed, the observable universe seems to unfold from such principles, and in this sense, it may be said that the principles are objectively real, more real perhaps than the tangible things we observe, and that essence precedes existence.
It is much this sort of essence that de Saussure assumed must underlie human systems of signification, and he prompted generations of scholars across many disciplines to seek these "deep structures" from which the practically infinite varieties of human performance emerge. It is true that such structures were assumed to be rooted in anatomy and physiology, particularly of the brain. The question is, does this mean that the deep structures of signification (and thus the performances they produce) are "merely artifacts" of a peculiar biological machine, that the whole system ultimately refers to nothing "real" except itself? Given the contingency of signifying performances, and indeed of the structural model itself, it is a tempting viewpoint.
But if the observable universe and all the things in it do emerge from a parsimonious and orderly set of seemingly abstract principles, then this is the same set of principles that produces the brain, which is the foundation of deep structure and thus of all signifying performances. So to say that language, for example, is merely a brain artifact that does not refer to the actual universe is to dismiss the proposition that both the brain and the universe emerged from the same order. The proposition shouldn't be dismissed without good reason, because if it is true, then we find that discovering something about "mere artifacts" and "abstract constructs" of our "peculiar machinery" is to discover something about the universe at large.
In short, we might find that we are really talking about something after all.
That's some intense philosphy. I like. I suppose I can't get my head out of the notion that everything is a human construct and therefore by defination it must limited by our means. I have to admit, having not read sartre i'm not as up on this kind of thinkng as you are but I think I see what you are saying.
I suppose comparing language to the laws of physics was a bad analogy as the existence of so many different languages proves that the sign/signifier relationshp is arbitrary. However, what you say about prediscovery in physics is very interesting. If what you say is true, and i've no doubt it is, then perhaps some some things really can be universal and essence sometimes does precede existence. Or rather, essence precedes our knowledge of existence. It's not that quarks didn't exist before we discovered them, that is to say, the things we signify as quarks. Personally i'd have called them flobadobs.
I'm intrigued by what you said about the brain and the universe 'coming from the same order.' What do you mean by this? Do you mean the brain is a machine like any other and conforms to the same mathematical laws? I know that in the next 20 or so years scientists will be able to recreate a human brain inside a computer. This may be a case of art imitating life, imitating art, if that's not too clumsy an expression. However I still think that human emotion and experience play too greater part in creating our 'constructs' for them to be completely objective.
Yo. Innit.