> On 11 Mar 2021, at 00:52, Tomas Pales <[email protected]> wrote: > > > > On Thursday, March 11, 2021 at 12:15:43 AM UTC+1 Brent wrote: > > > On 3/10/2021 2:41 PM, Tomas Pales wrote: >> >> >> On Wednesday, March 10, 2021 at 6:29:13 PM UTC+1 Brent wrote: >> >> >> On 3/10/2021 1:18 AM, Tomas Pales wrote: >> >> Then you've either (1) changed the meaning of "real" existence (2) changed >> the meaning of possible or (3) gone mad. >> >> As I said, possible means identical to itself. > > I know you said it, but that doesn't make it so. Is it possible that there > is a an even number greater than 2 which is not the sum of two primes? Is it > real? Is it possible that there is a cardinal number between aleph0 and > aleph1? Is it real? If you flip a coin is it possible it will come up > heads? What's the difference between "possible" and "necessary". > > If there is a contradiction in the definition of an object, that means that > the law of identity is violated and the object is not identical to itself and > hence is not possible. There is no difference between possible and necessary > in the absolute sense because every possible object exists necessarily in > reality as a whole. The distinction between possible and necessary is used > when talking about something that exists only in some possible worlds versus > something that exists in every possible world, respectively.
That is the alethic (Leibnizian) modal logic S5, which is the only one not obtained in the modal logics of self-reference. Possible P becomes not-provable-not P, that is consistent(P). We have to use the modal logic G for the 3p self-reference, then we get a logic S4 for knowledge and quantum logics for the notion of observable-predictible. In fact we get 8 logics of self-references, and each of them have their own notion of possibility and necessity, but none are even close to S5. Bruno > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/f42bfc0d-3c1f-47fc-9929-5fbaf44b0d60n%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/f42bfc0d-3c1f-47fc-9929-5fbaf44b0d60n%40googlegroups.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/6798862B-F6A5-4B9E-AA3A-9D8B042274B5%40ulb.ac.be.
