[HN Gopher] Mathematics, morally (2004) [pdf]
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       Mathematics, morally (2004) [pdf]
        
       Author : dang
       Score  : 31 points
       Date   : 2021-10-10 05:42 UTC (17 hours ago)
        
 (HTM) web link (eugeniacheng.com)
 (TXT) w3m dump (eugeniacheng.com)
        
       | Twisol wrote:
       | Strangely, by the end of page 23, I started to feel some
       | relevance to software engineering as well. For example, I'm not
       | satisfied to know that a feature is needed; I want to know _why_
       | the feature is needed and how it is hoped to be used. Simply
       | being told to make a change without context is singularly
       | frustrating to me.
        
         | amitport wrote:
         | "the client asked for it"
        
         | ordu wrote:
         | When you know why the change is needed, then you can answer
         | questions about this change. Like "how much latency we may
         | sacrifice to make it happen?" or "how much time I should spend
         | on this change to make it perfect?"
        
       | bmc7505 wrote:
       | I don't really understand how terms like "moral" or "faithful"
       | came to be adopted in mathematical parlance. I understand these
       | words are intended to convey some technical meaning, but why
       | muddy the waters between 'is' and 'ought'? As Hume recognized,
       | reason only teaches us about the way things are, not the way they
       | ought to be. What mathematicians do with that knowledge is in
       | their own hands.
        
         | bopbeepboop wrote:
         | "Moral" as I've heard it means something akin to "moral of the
         | story":
         | 
         | "This is morally correct, but suffers from a technical fault in
         | the naive approach."
         | 
         | ...is the same as...
         | 
         | "The higher order structure of this proof is a reasonable (and
         | ultimately correct) idea, but you can't use the most basic
         | encoding of your objects as parameters because of a
         | technicality, and instead must first transform the parameters
         | before being fed into the proof schematic."
         | 
         | ...and is akin to...
         | 
         | "Your password check function has the right logic, but you need
         | to filter inputs to prevent SQL injection."
         | 
         | Every field that has to make that kind of technical comment has
         | a language for it -- and for some reason, the analogy in
         | mathematics was between the moral of a story and the idea
         | behind a proof.
        
       | Ste_Evans wrote:
       | This paper is a good example of why mathematicians often ignore
       | philosophy of maths.
       | 
       | "When a community of mathematicians is small then our modern
       | standards of truth aren't necessary"
       | 
       | Proof is needed to provide confidence in the intuition. Lots of
       | historical examples of mathematical intuition unsupported by
       | rigorous proof going astray.
       | 
       | Also, on p11 it is not enough just to complete the square and
       | derive the formulae for quadratic roots, the substitution on p12
       | is also necessary. Otherwise, one has just shown the possible
       | form roots can take _if_ they exist, but not _that_ they exist.
       | 
       | i.e. showing A=>B is true, does not show that B is true.
        
         | boygobbo wrote:
         | To be fair, the paper is by a mathematician, not a philosopher.
         | The question is valid - what /do/ mathematicians mean when they
         | use the term 'morally'? It doesn't seem to have much to do with
         | what most people (including philosophers) think it means.
         | Rather, it appears from the examples given that it is
         | equivalent to 'by my gut feeling' which we might call
         | 'intuition' if that didn't have a more specific meaning wrt
         | mathematics (though, ironically, intuitionism would seem to fit
         | the author's position quite well, e.g. "The truth of a
         | mathematical statement can only be conceived via a mental
         | construction that proves it to be true, and the communication
         | between mathematicians only serves as a means to create the
         | same mental process in different minds."
         | https://plato.stanford.edu/entries/intuitionism/). Nothing
         | wrong with intuition as a starting point, but as you point out,
         | it surely can't be a justification in and of itself - what
         | happens when people's intuitions about what is right don't
         | agree? I wonder what discipline tackles that kind of problem..?
         | 
         | I also wonder how the author would react if a philosopher had
         | said they'd heard of this thing called 'Category Theory' and
         | thought it would be interesting to apply a topological
         | transformation to find the homomorphism between Kant and
         | Nietzsche and then started talking about the influence of
         | German beer on their thought? It would make about as much sense
         | as this paper.
        
       | Koshkin wrote:
       | A relevant quote from Feynman's Nobel Lecture used as the
       | epigraph in the preface to Visual Complex Analysis:
       | 
       |  _Theories of the known, which are described by different
       | physical ideas may be equivalent in all their predictions and are
       | hence scientifically indistinguishable. However, they are not
       | psychologically identical when trying to move from that base into
       | the unknown. For different views suggest different kinds of
       | modifications which might be made and hence are not equivalent in
       | the hypotheses one generates from them in ones attempt to
       | understand what is not yet understood._
        
         | dang wrote:
         | I think there's an analogous point to be made about programming
         | languages, which (if Turing-complete) are computationally
         | indistinguishable, but which lead people to have different
         | ideas when writing in them, and therefore lead to different
         | sorts of programs.
        
       | hanche wrote:
       | The date January 2004 is on the first page. So why does the post
       | title say (2017)?
        
         | dang wrote:
         | Oops! I went by the URL. Fixed now. Thanks!
        
       | Jensson wrote:
       | Mathematical proofs are like physics experiments, they are just
       | there to test your theory. But the other side of physics seems to
       | be missing from many mathematicians, theoretical physics where
       | you try to figure out interesting things that could be true and
       | should be tested. The math that is taught is only the
       | experimental math where you manually go through the math
       | experiments and verify them to be true, there is very little
       | about math theory building.
       | 
       | Edit: To clarify, math theory building was much more common a
       | century ago and before that. But then mathematicians started to
       | push out all the math that wasn't properly backed by proofs so
       | the entire field got transformed into mostly proof factories.
       | Having people build models that they cannot properly prove but
       | have nice properties and that others might later prove to be
       | correct/incorrect isn't a bad setup. Stuff like Riemann
       | hypothesis, Four color theorem etc are very valuable to have even
       | before they were properly proved, and we should try to create
       | more of that not discourage those. Instead mathematicians almost
       | completely stopped producing those.
        
       | ordu wrote:
       | Wow. I always thought of mathematics this way, but I didn't
       | understand it. Just... Wow. I had no words to speak it. I
       | remember my struggles with group theory, when I had all the
       | proofs, but it didn't make sense for me. Or elegant proofs which
       | doesn't explain anything at all.
       | 
       | It seems somehow to boil down to a question of "why". Something
       | is moral if it answers the question "why is it true". But to
       | answer a why-question we need to rely on a causal model, and
       | every person have his/her own causal model, so an answer may be
       | different for different people. Though it may be the same for the
       | most of people, because they share the same causal model or the
       | relevant part of it. So a moral mathematician needs to know the
       | accepted causal model and to fit moral explanations into it.
       | 
       | The only question remain: what is a causal model of mathematics.
       | I mean, if we find all possible causal models for mathematics,
       | then how we describe the set containing them all and only them.
        
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       (page generated 2021-10-10 23:01 UTC)