On Monday, February 28, 2022 at 4:52:11 AM UTC+1 meeke...@gmail.com wrote:
> > > On 2/27/2022 4:44 PM, Tomas Pales wrote: > > > On Sunday, February 27, 2022 at 11:45:32 PM UTC+1 meeke...@gmail.com > wrote: > >> >> >> On 2/27/2022 12:59 PM, Tomas Pales wrote: >> >> >> >> On Sunday, February 27, 2022 at 8:50:02 PM UTC+1 meeke...@gmail.com >> wrote: >> >>> >>> >>> On 2/27/2022 8:43 AM, Tomas Pales wrote: >>> >>> On Thursday, February 24, 2022 at 4:45:11 AM UTC+1 meeke...@gmail.com >>> wrote: >>> >>>> This should be of interest to all the everythingists on this list. I'd >>>> especially like to hear what Bruno thinks of it. It's a bit expensive, so >>>> I may wait for more reviews before I take it up. >>>> >>>> *Birmingham-based philosopher Alastair Wilson has taken up the >>>> Herculean task of putting modal realism and many-worlds quantum theory >>>> together into a coherent, unitary view of reality. The results of this >>>> effort have been presented in several papers in recent years, and are now >>>> assembled in this thought-provoking book. While, as we will see, questions >>>> remain, Wilson has no doubt managed to come up with ingenious new >>>> hypotheses and has proposed solutions to existing problems and, more >>>> generally, with a powerful new modal realist view. The resulting >>>> perspective will certainly be of interest in the coming years, especially >>>> for naturalistically inclined philosophers, demanding that metaphysical >>>> hypotheses be made as continuous with our best science as possible.* >>>> >>>> >>>> https://ndpr.nd.edu/reviews/the-nature-of-contingency-quantum-physics-as-modal-realism/ >>>> >>>> From the review I take it that Wilson has missed the intermediate kind >>>> of possibility, namely computability which is between logical possibility >>>> and nomological possibility. >>>> >>>> Brent >>>> >>> >>> I am not sure what is new here. Many-worlds interpretation of QM is >>> obviously an example of Lewis' modal realism in the context of QM. As was >>> discussed here some time ago, it may not even involve splitting of worlds. >>> That is, all the quantum parallel worlds may be distinct worlds (objects) >>> even before a measurement; they are just exactly the same before the >>> measurement (exact copies of each other) and they start to differ at the >>> measurement event. A regularity in the multiverse of these quantum worlds >>> manifests in the fact that the worlds start differing in proportions given >>> by the Born rule, based on the (same) state of the worlds at the moment of >>> measurement. >>> >>> More generally about possible worlds or objects, I still see no >>> difference between a world that is logically possible (consistent) and a >>> world that "exists". >>> >>> >>> Really? It is logically possible that you don't exist. So would the >>> world without you have no difference from this world? >>> >> >> A world without me is possible (logically consistent). A world with me is >> possible too, obviously. And so both worlds exist, because they are both >> possible. >> >> >> But they are certainly different. You tried to infer that they must both >> exist because there is no difference between the one with you, which exists >> by observation, and the one without you. >> > > No, I talked about two exactly same worlds (copies), with all the same > properties, and I asked what it would even mean if one of them existed and > the other didn't. > > > >> A logically possible world is a world that is identical to itself, that >> is, it has the properties it has and does not have the properties it does >> not have. If two worlds have all the same properties except the property of >> existence (one exists and the other doesn't) what does it even mean? >> >> >> That only shows that a given world must either exist or not exist. Maybe >> only worlds with Tomas Pales in them exist. That's a different property. >> > > It shows that if a given world is possible, it doesn't make sense to ask > whether it exists. Because there is no difference between being possible > and existing. > > > And you know this last how:? >> > > Because I see no difference between being possible and existing. > > > > So I see no alternative to modal realism. >> >> If we want to go into more details we may ask what properties a world or >> object may have and based on that we may differentiate between different >> kinds of worlds or objects, for example spatiotemporal worlds versus worlds >> that don't have a temporal or spatial structure. An important kind of >> property is relations between objects (relational properties), and the most >> general kind of relation is similarity, which holds between any two objects >> and thus is a necessary kind of relation. It just means that two objects >> have certain common properties and certain different properties. >> Mathematics as the most general study of relations explores the similarity >> relation as morphism in category theory and has reduced it to the set >> membership relation in set theory. Set theory is interesting to me in that >> it grounds mathematics in concrete worlds made of collections (sets), as >> opposed to abstract relations like numbers, functions, symmetries etc. >> >> But if all mathematically (structurally) and consistently characterized >> worlds/objects exist, it seems surprising that we live in a world with >> quite stable laws of physics that persist in time (along the time dimension >> of spacetime). Since reality is a mess of everything possible >> >> >> "Possible" is a rather ill defined concept and "everything possible" is >> even worse. "Logically possible" doesn't fix the problem. Logic is about >> language and propositions. What is logically possible depends on what >> rules of logic one adopts. Is it logically possible that Sherlock Holmes >> companion is both John Watson and James Watson? Does a contradiction imply >> everything? >> > > By "possible" I always mean logically possible (consistent) - an object is > possible if it has the properties > > > Properties are things we invent to describe objects. It's a muddle to >> imagine you can define objects by properties. Does my car have the >> property of being insurable? >> > > We need to define properties with precision in order to see if there is > any inconsistency between them. The ultimate level of precision is > mathematical precision where all relational properties are reduced to set > membership relations, thus reducing the structure of an object to a pure > set - that is, a set whose all members are themselves sets, all members > of its members are sets, and so on, down to empty sets or maybe even > without bottom. > > > So to know whether a world exist we must first reduce it's description to > mathematical relations between sets. Sets of what? What good is a > criterion that can never be checked. > The structure of every object should be reducible to a pure set, which is a set of sets of sets etc., down to empty sets. So in principle we could check the consistency of the structure by defining it as a pure set. But due to Godel's second incompleteness theorem we can't do even that because it is impossible to prove that set theory is consistent. But our inability to prove the consistency of an object has no impact on whether the object is consistent and thus whether it exists. We just know that if an object is not consistent it cannot exist because it is nonsense. that it has and doesn't have the properties that it doesn't have. In other words, it is identical to itself. That's classical logic, and the only kind of logic that makes sense to me. Then I suggest you read some books by logicians. > Will they explain what is a circle that is not a circle, and similar nonsense? No, about whether a true proposition requires that its referents exist. > Whether all propositions follow from a contradiction. The scope of > quantifications... Whether you can quantify over relations. Try > > > https://www.amazon.com/Thinking-About-Logic-Introduction-Philosophy/dp/019289238X/ref=sr_1_1 > > I think you have an impoverished view of logic. > But when I ask about what objects exist I am interested in objects that are defined consistently, objects that have the properties they have. An object that simultaneously has and doesn't have the property of circle is nonsense, so it can't exist. I don't care whether some paraconsistent logic blocks logical explosion from a contradiction or can be useful in analysis of contradictory data. -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/f6193123-ae0c-4f91-ae70-f6bb18d9868fn%40googlegroups.com.
