XPost: alt.philosophy, comp.theory   
   From: julio@diegidio.name   
      
   TL;DR: There is no such thing as an irrational reasoner,   
   i.e. not any more than there exists a married bachelor.   
      
   [ Original subject: "daily puzzle: the rational reasoner".   
      Salvaged from the Google Groups archive.]   
      
   On November 19 2023, Rich D wrote:   
    > On November 15 2023, Jeff Barnett wrote:   
    > >> A rational person believes a finite number of propositions;   
    > >> that is, he believes all of them they are true. (if he thought   
    > >> any one was false, he'd disbelieve it)   
    > >> A rational person also disbelieves in his own perfection.   
    > >> He expects to be wrong occasionally.   
    > >> This implies that one of the list of the propositions   
    > >> referenced above, must be false. And he's aware of this   
    > >> implication. Which means he believes he believes   
    > >> something false.   
    > >> Is this inconsistent? Is he rational? Explain.   
      
   Yes, it/he is: to begin with because incorrect is not   
   the same as incongruous ("inconsistent", though that   
   is more of a mathematical term).  Moreover, we indeed   
   do hypothetical thinking, which means thinking with the   
   (meta-)knowledge that not (and not ever) all (domain)   
   knowledge is accurate and available.  And so much more,   
   we do...   
      
    > > Rational does not imply perfection in thought.   
    >   
    > I would not define rational as equivalent to perfection.   
    > In order to discuss the concept, one must first define the concept.   
    >   
    > > You seem, above, to float a definition of a rational person then   
    > > move on to ask a question given your definition.   
    >   
    > Define rational person: he attempts to avoid contradiction,   
    > he doesn't knowingly accept any contradiction. He utilizes   
    > the precepts of first order logic.   
      
   No, he doesn't (or, shouldn't) use "FOL". To begin with,   
   do not conflate Logic proper (valid reasoning) with formal   
   and/or mathematical logic, not to even mention the unbounded   
   complexity of the real world.  At best Logic proper goes with   
   symbolic logic, whatever that even means...   
      
    > He attempts to recognize facts and reality,   
    > assuming his perceptions of reality are accurate.   
      
   Again, a rational thinker would never assume full   
   and fully accurate knowledge.   
      
    > He notices that no one is perfect. By induction, he presumes   
    > himself to be imperfect; that is, he's occasionally wrong. Which   
    > means one of his accepted propositions must be false.   
      
   Yes, "(he very well knows that) he may be wrong", put simply.   
      
    > Therefore, he is aware that he believes a false proposition.   
    > Hence is inconsistent. Knowingly.   
    >   
    > A modest man must therefore be inconsistent, unavoidably.   
      
   It ain't about "modesty", it's a matter of "finiteness",   
   and, to reiterate, it ain't about consistency either, a   
   _rational_ (hu)man *is* "consistent", in so far as s/he is   
   being rational, for what rational even means.   
      
    > > If the definition was of a abstract system (e.g., something in the   
   class   
    > > of Turing machines) you could ask if such a system could be   
   defined, not   
    > > whether it is consistent.   
    >   
    > You could frame the original question in regard to an abstract   
    > system, it wouldn't change anything pertinent.   
    >   
    > Here's a workaround: call on information theory. Assign b bits   
    > of information to each correct proposition. Then recognize that   
    > some of those are false, and strive to maximize the total   
    > information. Don't sweat the small stuff, I always say -   
      
   Sure, and we already do that, a logic of confidence instead of one   
   of certainty: by the lenses of an information-theoretic approach...   
      
   (so to speak).   
      
   But often there is more and better we can do than just "averaging"   
   "from the past": but indeed, contra widespread belief, inductive   
   reasoning is *not* probabilistic reasoning, it's not even reasoning   
   strictly speaking (P.F. Strawson, Introduction to Logical Theory),   
   it's rather *a premise to any reasoning and reasonability*.   
      
   And here is an evergreen for the broader context:   
   D.C. Williams, The Evils of Inductive Skepticism.   
      
      
   Julio   
      
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    * Origin: you cannot sedate... all the things you hate (1:229/2)