1Z, How do you define existence? For something to exist must it be something you can see and feel, or would you say it has to be something that can be studied objectively? Would you agree that for something to have objective properties, it must exist? Clearly there are things humans have discovered which we can't see or feel, but we think they exist because we see their effects: wind, dark matter, black holes, etc. Or theories suggest their existence: extra-solar life, strings, and so on.

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I would argue that mathematical objects exist because this universe's existence does not make sense in isolation. Imagine you were in a windowless bathroom. Should you doubt the existence of the rest of the world because you cannot see it, or would there be clues to support the existence of things outside that room? The finely tuned physical constants, laws, dimensions, etc. of this universe suggest that this universe is one of many, perhaps one among all possible structures. Just as we see the affects of wind and know it exists, one can look at the fine tuning of this universe and believe in the existence of all possible structures. Every such structure is a mathematical entity. If you doubt the existence of mathematical objects, how do you explain fine tuning? ( http://en.wikipedia.org/wiki/Fine-tuned_Universe ) Jason On Mon, Feb 7, 2011 at 4:55 PM, 1Z <peterdjo...@yahoo.com> wrote: > > > On Feb 7, 4:06 pm, Bruno Marchal <marc...@ulb.ac.be> wrote: > > On 06 Feb 2011, at 22:20, 1Z wrote: > > > > > > > > >>> On Feb 5, 7:43 pm, Bruno Marchal <marc...@ulb.ac.be> wrote: > > > > >>>> Computationalism needs Church thesis which needs AR (Arithmetical > > >>>> Realism). > > > > >>> Nope, just AT (arithmetic truth). > > > > >> Actually, comp needs only, for the ontology, the quite tiny complete > > >> Sigma_1 truth. > > > > > As I have stated many times, it doesn;t matter in the least > > > how many or few immaterial objects you attribute existence to. > > > It's like saying pixies exist, but only a few > > > > What? > > It is always better to make a theory precise. > > The theory that some precise number of pixies exist is just > as wrong as the theory that some indeterminate number exists. > > Mathematical anti realists hold that *no* mathematical > objects exist. And they still accept CT and all the rest. > > > >> Please don't put metaphysics where there is only > > >> religion > > > > > Believing in what is not proven is religion. I can > > > argue for anti realism. > > > > I argue in favor of nothing. > > You argue that some subset of mathematics has immaterial existence. > > >That's philosophy. You force me to be > > explicit on this; I do science. I am a logician, and I show that > > rational agent believing in comp believe that ... etc. I don't know > > about the truth. > > > > > > > > >> (saying yes to the admittedly betting doctor). > > > > > Saying yes to the doctor will not guarantee your > > > immaterial existence if there is no immaterial existence. > > > > But there is immaterial existence. > > To be fair, that's an unargued claim, not an argument. > > > I recall you that I say in the > > ontological context that something exist if Ex (bla-bla-bla x) is true > > in the standard model of arithmetic. > > Utterly wrong. In the *mathematical* context something > exists if there is a true backwards-E statement asserting > it, but the whole point of anti realism is that that is merely > game playing and does NOT imply RITSIAR ontological existence. > > >I use the standard meaning of > > existence of numbers, etc. > > As I have told you many times, there is no standard meaning. > > http://en.wikipedia.org/wiki/Philosophy_of_mathematics > > > > AR/Platonism is a separate assumption to yes Dr. > > > > I have drop out AR. You need AR (in which everyone believes except the > > ultrafinitists and the bad faith philosophers) to understand the term > > "digital" used by the doctor. > > No you don't. Mathematical anti realists can understand "digital > computer" > > > > > > > > <And with comp, > > >> it is math, indeed, even (full, above Sigma_1 arithmetic. > > >> Arithmetical realism is what you need to apply the excluded middle in > > >> computer science and in arithmetic. > > > > > The excluded middle is a much of a formal rule as > > > anthing else. Formalists can apply it, so it is compatible > > > with anti realism. > > > > The theory admits a formal study. You don't act like a formalist at > > all. The term "Formalism" makes not an atom of sense without > > arithmetical realism. > > Formalism is a major variety kind of anti realism. > > > In philosophy arithmetical realism is the weaker > > of all possible realism, except again for the ultrafinitists. > > The weakest kind is NONE WHATSOEVER....no pixies. Zip. Nada. > > > If you are formalist and anti realist on the numbers you are in > > contradiction, > > What contradiction? > > > or, once and for all, just replace numbers by the > > following formal expression 0, s(0), s(s(0)), etc. + the axioms I just > > sent to Andrew, etc. > > Yep. Formalism says you have rules, and you manipulate them > and certain things seem to move around a change, and we > call those sets and numbers....and they don't really exist. > When you switch off your PC there is no more Supermario, > and when you stop doing maths there are no more numbers. > > > > AUDA provides more than a formalism, > > I don;t mean "a formalism"=" a mechanisable system for applying rules" > > I mean "formalism"="the claim that mathematics is a game played > according to > various sets of rules and is not 'about' any real entity". > > I have pointed out the distinction to you many times > > >it provides an arithmetisation, > > which is a *weakening* of formalism, made possible by AR. GĂ¶del > > already exploited this. > > > > > > > > >> To understand the fundamental > > >> consequences of Church thesis you need to accept that some program > > >> computes function despite we have no means to know if it is total or > > >> partial, or that a program will stop or not. > > > > > And I can accept that by positing LEM as a formal rule. I don;t > > > have to posit an immaterial Plato's heaven > > > > I make clear that the immaterial Plato Heaven for the machine is just > > the truth of arithmletical proposition. > > Truth is not existence. > > >It is an non arithmetical > > notion, union of the entire Kleene-Mostowki arithmetical hierarchy, > > and well know non controversal mathematical object in the field of > > logic. > > Sighh.to anti-realists, all immaterial existence is controversial > > > I use the "immaterial Plato heaven" terminology, either as poetical > > shortcut, > > Well, it isn;t material since matter is some sort of iluusion within > it, according to you > > > or as a point in the arithmetical representation of some > > term in Plotinus theory. > > I explained this already to you, but you keep adding metaphysical > > stuff which don't exist. > > It's metaphyscial already. I exist , and you say I am a programme > that is not running on a physcial platform. That adds up to > a statement about existence. You are making a statement > about me, so you are making a statement about existence. > > You conclusion is ontological, so it either comes from > an ontological premise or it is a non sequitur. > > > > > >> Only ultrafinitist denies AR. > > > > > Wrong. Anti realists deny it. I have pointed this out many > > > times. You think the only debate is about the minimal > > > set of mathematical objects, and that is not the only debate. Anti > > > realists > > > can accept a maximal set of objects, with the proviso that their > > > existence is fictive and not real existence > > > > I am agnostic on all notion of existence. > > > All, except my own > > consciousness here and now. > > You keep insisting that some subset of arithmetic exists!!!! > > > I suggest a theory, and derive > > consequences in that theory. > > > > > > > >> AR+, the idea that we don't need more than AR, in this setting, is a > > >> consequence of the math. From 'outside' the tiny effective universal > > >> sigma_1 complete set is enough. from inside, even mathematicalism is > > >> not enough (it is more 'theologicalism'). > > > > >>> The ontological status of > > >>> mathematical > > >>> objects is a area of contention in metaphysics, and not > > >>> straightforwardly > > >>> proven by mathematics itself. > > > > >> With comp, you don't need more than the part on which almost > > >> everybody > > >> agrees: arithmetical realism. > > > > > Anti realists do not agee on the real existence of any > > > part. There are no pixies at all, not just a few pixies. > > > > If you believe in prime numbers, > > I don't. No pixies means no pixies. > > > and if you are patient and good > > willing, I can explain that there are all universal numbers, and why > > assuming comp that's enough and that's necessary to solve the white > > rabbit problem. And that postulating physical laws miss the > > epistemological existence of the qualia. > > The basic ontology is not important. If you take less than a universal > > system (like numbers, combinators, ...) you don't have enough for > > comp, if you take more you miss the qualia. > > > > No problem with a formalist interpretation of all this. Actually S4Grz > > formalize at the meta-level what the machine can uderstand to be non > > formalisable (like consciousness). > > > > > > > > >> The engineers, the scientists, most > > >> philosophers. > > >> Except for Thorgny Tholerus I never met an ultrafinitist. You don't > > >> have to decide if numbers are idea of the mind or sort of angel in > > >> Plato Heaven. With comp the very idea of number will itself be a > > >> number, a sort of second order number, relative to universes > > >> (universal numbers). > > > > > ULtrafinitism has nothing to do with it. For formalists > > > no number exists. They have no prejudice about any kind, > > > > If comp is false because, according to you 7 does not exist, then it > > is your problem. > > I never said that. The whole point is that comp and AR are *separate* > assumptions. The one is *not* a corollary of the other > > > I told you that I am working in a theory, which is neutral on those > > question. Formalist have normally less problem with a tiny sigma_1 > > arithmetic than with the real or complex numbers. > > Anti realist formalists, and any other kind of anti realists > DO NOT ACCEPT THE REAL EXISTENCE OF ANY MATHS AT ALL. > > *****Nooooooooo******* pixies! > > > I just don't believe you don't believe in seven. > > Well, I don't. And I have been having the same argument with you > for years, and you really need to stop thinking in your box. > > >You confuse > > 'immaterial' with 'inexistent'. > > > > If you don't believe in seven, do you still believe in the formal > > expression s(s(s(s(s(s(s(0))))))) ? > > I believe in the pixels I am looking at..which are material. But that > is the existence of pixels, not of numbers or sets. > > > >>>http://en.wikipedia.org/wiki/Philosophy_of_mathematics > > > > >>>> And you cannot refute an argument by anticipating a refutation. > > >>>> So if > > >>>> you have a refutation of MGA you should present it. > > > > >>> See Colin Klein;s refutation of Maudlin's Olympia. > > > > >> We have already discussed this and Colin Klein does not touch the > > >> movie graph argument. > > > > > Then you had better stop saying the MGA and Olympia are equivalent > > > > The movie graph *argument*, is not attacked by Klein. Klein attacks > > the Olympia *argument*. > > When I say that Olympia and MGA are equivalent, I am talking about the > > conclusion, not about the arguments leading to the conclusion. > > > > Bruno > > > > http://iridia.ulb.ac.be/~marchal/ > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To post to this group, send email to everything-list@googlegroups.com. > To unsubscribe from this group, send email to > everything-list+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/everything-list?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.