cugini@ICST-ECF.ARPA (06/29/87)
Harnad writes: > In responding to Cugini and Brilliant I misinterpreted a point that > the former had made and the latter reiterated. It's a point that's > come up before: What if the iconic representation -- the one that's > supposed to be invertible -- fails to preserve some objective property > of the sensory projection? ... The reply is that an analog > representation is only analog in what it preserves, not in what it fails > to preserve. Icons are hence approximate too. ... > There is no requirement that all the features of the sensory > projection be preserved in icons; just that some of them should be -- > enough to subserve our discrimination capacities. > ... But none of this > information loss in either sensory projections or icons (or, for that > matter, categorical representations) compromises groundedness. It just > means that our representations are doomed to be approximations. But then why say that icons, but not categorical representations or symbols are/must be invertible? (This was *your* original claim, after all)? Isn't it just a vacuous tautology to claim that icons are invertible wrt to the information they preserve, but not wrt the information they lose? How could it be otherwise? Aren't even symbols likewise invertible in that weak sense? (BTW, I quite agree that the information loss does not compromise grounding - indeed my very point was that there is nothing especially scandalous about non-invertible icons.) Look, there's information loss (many to one mapping) at each stage of the game: 1. distal object 2. sensory projection 3. icons 4. categorical representation 5. symbols It was you who seemed to claim that there was some special invertibility between stages 2 and 3 - but now you claim for it invertibility in only such a vitiated sense as to apply to all the stages. So a) do you still claim that the transition between 2 and 3 is invertible in some strong sense which would not be true of, say, [1 to 2] or [3 to 4], and b) if so, what is that sense? Perhaps you just want to say that the transition between 2 and 3 is usually more invertible than the other transitions ? John Cugini <Cugini@icst-ecf.arpa> ------