Chris F Clark wrote: > Chris F Clark (I) wrote: > > > I'm particularly interested if something unsound (and perhaps > > ambiguous) could be called a type system. I definitely consider such > > things type systems. > > "Marshall" <[EMAIL PROTECTED]> wrote: > > > I don't understand. You are saying you prefer to investigate the > > unsound over the sound? > ... > > Again, I cannot understand this. In a technical realm, vagueness > > is the opposite of understanding. > > At the risk of injecting too much irrelevant philosophy into the > discussion, I will with great trepdiation reply.
I agree this is OT, but I'm not sure about the source of trepidation. > First in the abstrtact: No, understanding is approximating. Agreed. > The world is inherently vague. Our understanding of the world is vague. The world itself is not at all vague. > We make false symbolic models of the world which > are consistent, but at some level they do not reflect reality, Yes... > because reality isn't consistent. What?! > Only by abtracting away the inherent > infinite amout of subtlety present in the real universe can we come to > comprehensible models. Sure. (Although I object to "infinite.") > Those models can be consistent, but they are > not the universe. The models in their consistency, prove things which > are not true about the real universe. Sure, sure, sure. None of these is a reaon to prefer the unsound over the sound. > Now in the concrete: In my work productivity is ultimately important. > Therefore, we live by the 80-20 rule in numerous variations. One of > ths things we do to achieve productivity is simplify things. In fact, > we are more interested in an unsound simplification that is right 80% > of the time, but takes only 20% of the effort to compute, than a > completely sound (100% right) model which takes 100% of the time to > compute (which is 5 times as long). We are playing the probabilities. What you are describing is using a precise mathematical function to approximate a different precise mathematical function. This argues for the value of approximation functions, which I do not dispute. But this does not in any way support the idea of vague trumping precise, informal trumping formal, or unsoundness as an end in itself. > It's not that we don't respect the sound underpining, the model which > is consistent and establishes certain truths. However, what we want > is the rule of thumb which is far simpler and approximates the sound > model with reasonable accuracy. In particular, we accept two types of > unsoundness in the model. One, we accept a model which gives wrong > answers which are detectable. We code tests to catch those cases, and > use a different model to get the right answer. Two, we accept a model > which gets the right answer only when over-provisioned. for example, > if we know a loop will occassionaly not converge in the n-steps that > it theoretically should, we will run the loop for n+m steps until the > approximation also converges--even if that requires allocating m extra > copies of some small element than are theoretically necessary. A > small waste of a small resource, is ok if it saves a waste of a more > critical resource--the most critical resource of all being our project > timeliness. Υes, I'm quite familiar with modelling, abstraction, approximation, etc. However nothing about those endevours suggests to me that unsoundness is any kind of goal. > Marshall's last point: > > > I flipped a coin to see who would win the election; it came > > up "Bush". Therefore I *knew* who was going to win the > > election before it happened. See the probem? > > Flipping one coin to determine an election is not playing the > probabilities correctly. You need a plausible explanation for why the > coin should predict the right answer and a track record of it being > correct. If you had a coin that had correctly predicted the previous > 42 presidencies and you had an explanation why the coin was right, > then it would be credible and I would be willing to wager that it > could also predict that the coin could tell us who the 44th president > would be. One flip and no explanation is not sufficient. (And to the > abstract point, to me that is all knowledge is, some convincing amount > of examples and a plausible explanation--anyone who thinks they have > more is appealing to a "knowledge" of the universe that I don't > accept.) I used a coin toss; I could also have used a psycic hotline. There is an explanation for why those things work, but the explanation is unsound. > Look at where that got Russell and Whitehead. Universal acclaim, such that their names will be praised for centuries to come? > I'm just trying to be "honest" about that fact and find ways to > compensate for my own failures. Limitation != failure. Marshal -- http://mail.python.org/mailman/listinfo/python-list