Talk:Modal realism

I put a little more information in here, but the topic is far from complete. For one thing it lacks some treatment to the objections to this worldview. I hope to find and distill some of them in the near future DV8 2XL 22:32, 28 August 2005 (UTC)

Could you put in a section responding to the objection to King's argument made by Dodger below? I realize it is against Wikipedia guidelines to include original research, but the argument seems to have such an obvious flaw I feel it is irresponsible to leave it as is without addressing Dodger's objection. How does King respond to this issue, as he must surely have noticed it? I do not have access to King's work. k0hlrabi

I quite agree with k0hlrabi, and largely with Dodger, except for his suggestion that the King argument (as set forth on the main page at least) rises to the level of Russell's paradox. Russell's paradox made sense because one of the claims of the type of set theory Russell was criticizing was that it was acceptable to define sets in the abstract manner in which Russell did. The King argument (again, as set forth on the main page) does not make sense in the same way because it depends on a premise that does not follow from possible worlds theory. Specifically, the argument assumes that the falsity of modal realism constitutes a "way a possible world could be." But modal realism is a statement about *all* possible worlds, not about only one possible world. Even if one were to concede that the falsity of modal realism is a "possible" statement, it is one about the universe of possible worlds, not about a particular world. Possible worlds theory never held that all "possible" statements about the universe of possible worlds are instantiated in a possible world.

If, moreover, the hypothesis about the possibility of the falsity of modal realism were reduced to a statement about a single world, it would simply be a statement that "this [possible] world is not real." But to say that such a statement is possible is to hypothesize that modal realism is false, not just that it is possibly false. On this reading, therefore, King's has merely succeeded in reasoning from not P to not P. Which reminds me of a joke.... Mds001 01:20, 9 February 2006 (UTC)

You're both rather new to the Wiki, I see so please take this as friendly advice. One: place new comments at the bottom of the page - it helps others folowing the thead. Two: 'I realize it is against Wikipedia guidelines to include original research' is an error - it's against Wikipedia policy to include original research. Three: this is an work-of-record, not a platform for debate - submitions must be Neutral POV WP:NPOV not All POV's. --DV8 2XL 02:35, 9 February 2006 (UTC)

On causal isolation

I am new to this talk section, so please mail me at henry.story@bblfish.net if I make a mistake. In his collected papers, David Lewis defines causality as a relation between events such that

 e1 causes e2 if and only if
    if e1 had not happened then e2 would not have happened

which due to his analysis of counterfactuals comes to

 e1 causes e2 if and only if
   in the closest possible worlds in which e1 does not happen, e2 does not either

In this sense possible worlds in David Lewis' sense are not really causally isolated, since causality is a relation between possible worlds. In other words saying that something causes something else is to make a statement of the relation between possible worlds.

Now it is true that doing something in this world does not cause it to happen in another world. But that is just because that statement does not make sense.--Bblfish 13:32, 15 October 2006 (UTC)

Insert possible reference to Heinlein's "The NUmber of the Beast" as a literary treatment of this view? 203.167.75.51 07:22, 13 April 2007 (UTC)

See pantheistic solipsism 1Z 16:34, 13 April 2007 (UTC)

Criticizing modal realism

I added this section but forgot to mention it in comments

• Nice clean-up, Velho, and thanks (was going to get around to it, saved me the trouble) and yes I didn't see that POV issue thanks for catching it.

---

I wrote this a bit ago, but feel it was too hard to decipher... I'm rephrasing:

"It is possible that modal realism is wrong, and that another theory, offering the same benefits but entailing the existence of only one world (this one), is correct. Translated into the terms of possible world theory:

There is at least one possible world at which modal realism is wrong, and at which another theory, offering the same benefits but entailing the existence of only one world (itself), is correct. "

This involves accepting the conjecture that there is, in fact, one possible world at which model realism is wrong as fact.

It seems to me that the argument here is based on a premise that the observer has to take at face value, and may be due to a misinterpretation on the part of the arguers against.

Nothing prevents modal realism to be 100% correct in that all possible universes exist. The argument supplied only proves that it's not possible (in any universe) that all *conceivable* universes exist.

In other words, the supposed paradox vanishes instantly when one simply replies 'there is NOT one possible world in which modal realism is wrong. Modal realism is correct in ALL worlds, as it applies not to any individual world but to a metagroup of all possible universes. To this extent, the presumed paradox is in error, effectively being a form of Russell's paradox. The rules that apply to and define the proper class of all possible universes are not the same ones that apply to the individual universes within. The only rule that applies to the universes themselves is that they are, in fact, possible, which, in the scope of the multiverse itself, one which is not in that multiverse (which contains a number of universes) is not possible.

• I hate to put a damper on what is an interesting take on this subject, but you should supply supporting references to these statments as there is a prohibition on orignal research at Wikipedia. DV8 2XL 23:44, 17 September 2005 (UTC)

I can't see how something so obvious could be termed 'research.'

Dodger 03:51, 18 September 2005 (UTC)

Inability to comprehend is not a virtue. To put it simply, arguments and claims (including a claim that some argument or claim is obvious) that originate from editors are not proper Wikipedia content.

The arguments against modal realism also failed to cite sources (except Lewis himself, and merely to state the original statement the argument against is working towards), and were therefore apparently also original research.

tu quoque argument ... and no, no such thing is apparent. Missing citations are not the same as original research.

I've removed it in accordance with that exact same rule. If the restriction disallows the obvious flaw in the criticism of modal realism presented, than the restriction also disallows the uncited criticism itself.

Sounds like spite. And given how badly your logic sucks, you should not be editing anything related to it.

The section WAS cited: if you look at the references you will see, David Armstrong, A Combinatorial Theory of Possibility (1989; Cambridge University Press. That which you petulantly removed was paraphrased from that source.DV8 2XL 00:48, 20 September 2005 (UTC)

I restored the section and added detailed references and sources. DV8 2XL 03:40, 20 September 2005 (UTC)

I didn't remove anything petulantly. I would appreciate your remaining within the Wikipedia guidelines on civility by not deliberately using inflammatory and uneccesary adjectives.

Of course you did.

Further, I'm stating here that the section was not properly cited previously. The David Armstrong citation was given as a source for ONE of the possible results of the argument being correct, not as a source for the argument itself.

Dodger 14:25, 27 September 2005 (UTC)

• I rest my case. DV8 2XL 16:00, 27 September 2005 (UTC)

I beg your pardon? Dodger 09:35, 3 October 2005 (UTC)

I'm sorry, I thought that was just a figure of speech. Case closed.

I had a chance encounter with David Lewis at Wesleyan University. I was in his office to ask about a course in the phil dept. I had the distinct impression he did not want me in there, so I left. I wanted to ask him if he was familiar with a book written in Feb. 1971 and published in 1972 (Seth Speaks by Jane Roberts) that goes into detail about probable worlds, or possible worlds. Was his idea one of those things that seems to pop up simultaneously with others similar to it or was he aware of the Jane Roberts book? ( is this a good place to ask?)

Re;Peter King- If Lewis says " absolutely every way that a world could possibly be is a way that some world is." Could he be refering to the quantum possibilities? If there are possible worlds, it would not make sense if it/they had the restriction you posit. Maybe the process that created possible worlds could not create or form King's impossible world. (look in the index of 'Seth Speaks" by Jane Roberts,1972, 'probable worlds' for an interesting read ) Yes, I do believe. My phil prof at Uconn, Paul Bloomfield, was stunned to hear that admission.

Lewis' possible worlds aren't the branching worlds of quantum physics, largely because such worlds are causally related, and Lewis's worlds aren't. Nor are they the parallel worlds of science fiction. I didn't get the reference to impossible worlds; there are philosophers who argue for something like impossible worlds (Graham Priest is the main culprit), but it's not clear to me that it makes any sense. --Mel Etitis (Μελ Ετητης) 09:49, 9 February 2006 (UTC)

I have removed the section "Criticizing modal realism", since it was based almost solely on a minority unpublished view. It was also poorly written, with much unexplained detail and unhelpfully technical language, without links to assist readers. I intend to write something to replace it, reflecting main published objections to Lewis's theory. Noetica 02:44, 5 July 2006 (UTC)

I added a POV tag to the "Criticism" section. It's not reasonable to lift a summary of counterarguments to Lewis theory fully from Lewis own book, no matter what previous author of this section may think. According to the biographical page on Lewis, a very small minority of contemporary philosophers accept Lewis theory of modal realism. If that description is accurate then it can not be impossible to find a better source for other perspectives on Lewis work than Lewis himself.

RandySpears

Criticisms

I removed the statement "and thus far has resisted all attempts at definitive refutation" -- that is, and I think will be for a long long time -- a matter of opinion. Moreover, I agree that we need criticisms *other than* those enumerated (and then refuted) by Lewis himself. I'm thinking off the top of my head of Stalnaker and Kripke, but I'm sure there are others that are worth citing here; I'll see what I can find and add them in. In that case the current section with Lewis' arguments should be shortened to give due weight. BrideOfKripkenstein (talk) 20:27, 24 July 2010 (UTC)

Multiverses

Under "The term *possible world*" it says "To note, however, though the concept does sound similar to modern notions of a multiverse, in reality these two concepts are quite distinct – a multiverse would constitute (or be part of) a single possible world." Doesn't this really depend on whether dufferent parts of such a multiverse can causally affect one another? The difference between the Copenhagen and Many Worlds interpretation of quantum mechanics, is that Copenhagen is essentially the same as Many Worlds except that it asserts that only the part of the multiverse that can directly affect the observer is "real". Modal Realism would unite the two interpretations into one. Similarly, these String Theory notions that universal constants could take on many different values don't imply that there is any way to communicate information between universes. The only motivation for saying they arevall "real" rather than merely "possible" is solve the perceived issue of "fine-tuning", whereby most "possible" universes supposedly could not possibly support anything like intelligent life, or even atoms. Thus, couldn't these multiverse theories constitute subsets or sub-continua of the set of all possible worlds, rather than single ones? Also, the entire section I refer to contains no citations, like much of the article. DubleH (talk) 22:05, 21 August 2021 (UTC)

Thanks for pointing this out. The claim in the article about the relation between the concepts of possible world and multiverse is not obvious. Unless a source can be found, I suggest that we remove the sentence: "To note, however, though the concept does sound similar to modern notions of a multiverse, in reality these two concepts are quite distinct – a multiverse would constitute (or be part of) a single possible world." If there is a source, it might be a good idea to explain how the term multiverse is defined to show how they are different. Phlsph7 (talk) 05:23, 22 August 2021 (UTC)