I am afraid Telmo is quite right. There is no space for existence in Logic. That is not to say that I think Logic suffers from epistemological banality, not at all, I believe there are "holes" in Logic, areas, surfaces and constructions that need meta-investigation, inquiry. But in its standard forms logic is a production system that produces a set P' of propositions, some of which will be inconsistent with a subset A' of axioms, and thus "false" (I am not being very technical here, I am quite sure "production" means going from truth to truth, but whatever, construction). There are three obvious way to tweak a Logic of this kind, to fool around with the Axioms, to keep producing weird or not so weird but convoluted propositions and to "pull some props out of thin air" or intuition or whatever and check their consistency - all three are expected to be part of a natural intellect I should say. The truth is not Truth as such, it is a label that could have been Mars and Venus, and the main reason we work with the small set of axioms is what I would call he mirror symmetry effect, ie the observation that it is just as hard to win a lottery picking 1 correct number out of 49, or equivalently picking 48 correct numbers out of 49 - both mathematically equivalent, mentioning one number is the more practical option.
All of this is not suggesting that existence suffers from epistemological banality either :) AT > On 23.09.2014, at 16:21, Piaget Modeler via AGI <[email protected]> wrote: > > In addition if we are dealing with a knowledge base, then we have two > operations: assert and retract. > > When we assert P, or assert (not P), we are asserting that P is true, or (not > P) is true. > > When we retract P, or retract (not P), what is the meaning there? (Use > either closed or open world assumptions?) > > Kindly advise. > > ~PM > > From: [email protected] > To: [email protected] > Subject: RE: [agi] Logical Conflation > Date: Tue, 23 Sep 2014 07:08:26 -0700 > > Someone else proposed (a) (b) and (d) as the case. > > If only (a) and (d) are correct in your opinion, do you also subscribe to the > correspondence theory of truth, > that the truth of a proposition means the proposition corresponds to some > state of affairs in reality? > > What is your notion of truth? > > Michael. > > Date: Tue, 23 Sep 2014 12:03:34 +0200 > Subject: Re: [agi] Logical Conflation > From: [email protected] > To: [email protected] > > Hi PM, > > I am not a logician but here's my take: short story, the answers are (a) and > (d). I think you are confusing propositions with entities. A proposition is, > by definition, something that entails a truth value. > > P is a proposition. "P is false" is also a proposition, usually written ~P. > "P exists" is also a proposition, but I would say it's meaningless. Consider > the proposition A = "my dog is a german shepard". What does it mean to say > that A exists? On the other hand, the proposition B = "my dog exists" can be > true or false. > > Cheers > Telmo. > > On Tue, Sep 23, 2014 at 5:28 AM, Piaget Modeler via AGI <[email protected]> > wrote: > Logic seems to conflate many notions. I'm trying to disentagle these meanings. > > Two statements: > > P #1 > (not P) #2 > > What does statement #1 mean? > > P is true (a) > P exists (b) > something else (c) > > > What does statement #2 mean? > > P is false (d) > P does not exist (e) > something else (f) > > > Aren't these statements along two different dimensions (viz. truth, > existence)? > If (c) or (f) then what is the something else? > > > Kindly advise. > > ~PM > AGI | Archives | Modify Your Subscription > > AGI | Archives | Modify Your Subscription > AGI | Archives | Modify Your Subscription > AGI | Archives | Modify Your Subscription ------------------------------------------- AGI Archives: https://www.listbox.com/member/archive/303/=now RSS Feed: https://www.listbox.com/member/archive/rss/303/21088071-f452e424 Modify Your Subscription: https://www.listbox.com/member/?member_id=21088071&id_secret=21088071-58d57657 Powered by Listbox: http://www.listbox.com
