>> (there will be some isomorphism between a thing and a description of a >> thing, right? > > Absolutely not. Descriptions are not in any way isomorphic to the things they > describe. (OK, some 'diagrammatic' representations can be claimed to be, eg > in cartography, but even those cases don't stand up to careful analysis. in > fact.)
Beh! Some isomorphism is all I ask for. Take your height and shoe size - those numeric descriptions will correspond 1:1 with aspects of the reality. Keep going to a waxwork model of you, the path you walked in the park this afternoon - are you suggesting there's no isomorphism? > ** To illustrate. Someone goes to a website about dogs, likes one of the > dogs, and buys it on-line. He goes to collect the dog, the shopkeeper gives > him a photograph of the dog. Um, Where is the dog? Right there, says the > seller, pointing to the photograph. That isn't good enough. The seller > mutters a bit, goes into the back room, comes back with a much larger, > crisper, glossier picture, says, is that enough of the dog for you? But the > customer still isn't satisfied. The seller finds a flash card with an > hour-long HD movie of the dog, and even offers, if the customer is willing to > wait a week or two, to have a short novel written by a well-known author > entirely about the dog. But the customer still isn't happy. The seller is at > his wits end, because he just doesn't know how to satisfy this customer. What > else can I do? He asks. I don't have any better representations of the dog > than these. So the customer says, look, I want the *actual dog*, not a > representation of a dog. Its not a matter of getting me more information > about the dog; I want the actual, smelly animal. And the seller says, what do > you mean, an "actual dog"? We just deal in **representations** of dogs. > There's no such thing as an actual dog. Surely you knew that when you looked > at our website? Lovely imagery, thanks Pat. But replace "a novel written by a dog" for "dog" in the above. Why should the concept of a document be fundamentally any different from the concept of a dog, hence representations of a document and representations of a dog? Ok, you can squeeze something over the wire that represents "a novel written by a dog" but you (probably) can't squeeze a "dog" over, but that's just a limitation of the protocol. There's equally an *actual* document (as a bunch of bits) and an *actual* dog (as a bunch of cells). Cheers, Danny. -- http://danny.ayers.name
