[ExI] Modal Realism and Leibniz: (was The Many Dimensional Sculpture)

[Lee Corbin]

Bryan writes in

----- Original Message ----- 
From: "Bryan Bishop" <kanzure at gmail.com>
Sent: Tuesday, March 11, 2008 8:22 AM

> I would not have expected an implicit connection between MWI and modal
> realism per Rafal's message. However, I took this opportunity to go look at
> the Wikipedia article http://en.wikipedia.org/wiki/Modal_realism
> and I see what you mean:
> 
>> Modal realism is the view, notably propounded by David Lewis, that
>> possible worlds are as real as the actual world. It is based on the 
>> following notions: that possible worlds exist; possible worlds are not 
>> different in kind to the actual world; possible worlds are irreducible 
>> entities; the term "actual" in "actual world" is indexical.    

As is so often the case---Singularity Be Praised---Wikipedia rises
to the challenge brilliantly: http://en.wikipedia.org/wiki/Possible_world

    Comparison with the many-worlds interpretation

    The concept of possible worlds has sometimes been compared with the many-worlds
    interpretation of quantum mechanics; indeed, they are sometimes erroneously
    conflated. The many-worlds interpretation is an attempt to provide an
    interpretation of nondeterministic processes (such as measurement) without positing
    the so-called collapse of the wavefunction, while the possible-worlds theory is an
    attempt to provide an interpretation (in the sense of a more or less formal
    semantics) for modal claims. In the many-worlds interpretation of quantum
    mechanics, the collapse of the wavefunction is interpreted by introducing a quantum
    superposition of states of a possibly infinite number of identical "parallel
    universes", all of which exist "actually", according to some proponents. The
    many-worlds interpretation is silent on those questions of modality that
    possible-world theories address.

    Major differences between the two notions, aside from their origins and purposes,
    include:

        * The states of quantum-theoretical worlds are entangled quantum mechanically
           while entanglement for possible worlds may be meaningless;

        * according to a widely held orthodoxy among philosophers, there are possible
           worlds that are logically but not physically possible, but quantum-theoretical
           worlds are all physically possible.

    Given that both possible-world theories and quantum many-world theories are
    philosophically contentious, it is not surprising that the precise relations
    between the two are also contentious.

So my guess wasn't too far off!

> Hrm. I really would like to add some Leibniz in on this. How could 
> possibilities be as real as actualities? Let me reform my question. Is 
> he saying that possibilities exist in the sense of mental constructs, 
> such that one's lack of knowledge of the world essentially makes the 
> world both the 'real' and the 'possible' as you recursively explore it 
> and make your own representation?

Alas, I'm no expert on Leibniz. Alas, I'm no beginning student of
Leibniz.  Alas, I hardly rate even as a complete ignoramus on Liebniz's
philosophical views.  But I'd be all ears for what you or others have
to say.

> A vague, fuzzy set of what the world may or may not be, allowing
> subjective agents to explore it without messing up too much. Or is he
> saying that, metaphysically, the possibilities are as real as anything else?

Help. Anyone familiar with Leibniz at all on this score?

> Charles S. Peirce would have something to say about this use of
> the word 'possibility' since, naturally, it is more tied to the human
> mind, and he really, really disliked anybody saying something was
> 'possible' when they did not have the true source code to the
> universe to figure out the likelihood of something occurring or
> whether or not something was truly valid given whatever underlying
> laws of the universe there exist (whether a cellular automata rule or
> not, just so I can get in my mention of Wolfram and von Neumann etc.). 

So what---Peirce wanted to do to "possible" what I want to do to "qualia"?
That is, prescribe enough laws forbidding its use so that the user to
can be successfully prosecuted, and probably suffer sanctions, fines,
and solitary confinement somewhere?

> Is Lewis saying that possibilities exist (in the sense that a mental 
> agent can rationalize that something might be 'possible' given his 
> limited understanding of the greater world), or that if we allow 
> such 'possibilities' we automatically must acknowledge their full and 
> total existence? 

As you saw, Rafal answered

> ### The way I see it, everything exists. I mean it in the hardcore
> metaphysical sense - whatever it means to "be", everything you
> can think of and a lot more, have this property. Even contradictions,
> even inconsistent logic, even mathematical impossibilities exist, as
> hard [real] as rocks, except we are not there to touch them. 

and that seems like maybe what Lewis was saying indeed.

> I like to use Leibniz's optimism and his definitions from time to time:
> 1) real - necessarily existent
> 2) impossible - necessarily nonexistent
> 3) possible - unnecessarily nonexistent
> And a few others. I realize now that I cannot recall a link that 
> explains this terminology, but I do think it is still useful here since 
> it ties possibilities/reality/actuality back to terms re: necessity and 
> coherency.

Thanks.  Sounds useful to remember this about the views of the great
Hannover genius.

> [Lee wrote]
>> [Rafal wrote... or was it Bryan?]
>> > This form of self-correlation may be the necessary (although
>> > perhaps not sufficient) condition for  conscious experience. So
>> > you could say that consciousness is a property of self-correlated
>> > structures, existing timelessly as parts of the larger branching
>> > chains of world-states.
>>
>> I presume that these are the SAS (self aware structures) described by
>> Tegmark.
> 
> Why would SASes be needed?

Well---SAS means "self-aware-structure", no?  Certainly sounds to
me that Tegmark wants to identify conscious entities with SASs.

> If anything it should be more like an observer bias to calculate out
> [overcome?] due to the anthropic principles and so on, since all
> subjective agents would present a slightly different bias in consciousness
>  or awareness;

A classic example of a sentence needed a follow-up or two:  "That is, ...",
and "In other words....".  I'm having trouble parsing that.

> in more hard sci-fi terms, I'd argue that consciousness may not even
> exist, despite my experience and my mind, it's not a magical sauce. :)

Well, now that I've come out of the closet about some GLUTs being
zombies, I could start with the incendiary remark that consciousness
is the chief characteristic separating zombies from other passers of
Turing Tests, e.g., us, and other passers for what we ordinarily think of
as conscious entities (e.g. crows, parrots, chimps, dogs, liberals, etc.)

>> [Bryan wrote]
>>
>> > Like a GLUT (Giant Look-Up Table) of you? And this is the only
>> > you, the one and unique representation and the time/place of your
>> > consciousness?

Oh no.  A particular GLUT in my original usage re consciousness
focused on a strictly limited period in an entity's life. In other words,
take an amount of time necessary to administer a Turing Test (or
any other test you have in mind of finite duration), and create a
GLUT that would answer just the same no matter what you ask
the testees, human or GLUT. Sorry if I didn't make that clear.

But now you're proposing a GLUT to characterize a person's
whole life, and for me, that doesn't work at all, because a person
(to me) travels through a trajectory in the space of all possible
people (subspace of all possible algorithms). I hope it's not
necessary to extend the already mind-bending notion of a GLUT
that can successfully pass a limited interrogation.

> [Lee wrote]
>> Of course, as you know, this is at extreme variance with our
>> normal usages of the words "you" and the time/places of your
>> consciousness. For example, either under modal realism or the
>> MWI, something extremely similar to me (under the conventional
>> meanings of words) actually received a phone call a few minutes
>> ago, and so is not typing this. It's a "possible world" under
>> modal realism, and equally real under the MWI. Below, you use
>> "versions of you" to talk about, for example, those Rafals who
>> get to live forever, or those Lees who got a phone call.
> 
> I was not expecting this diversion. Given the distinctions I made above, 
> if we discuss them some more, and it turns out that Lewis and his modal 
> realism is more about subjective agents and their GLUTs,

Yikes! as said, I recoil from any but a very limited very *particular*
GLUT covering, for example, a particular testing situation. I wouldn't
even know where to start to make a GLUT for Rafal's Tree or my
platonic fuzzy sphere of what a person is in configuration space.

> rather than a metaphysical ensemble, then I think that you would
> have to drop your MWI tie-ins.

Wikipedia's two asterisk's items above already limit the connection
between modal realism, and the MWI.  It's not clear to me that you
are adding to the criticism, but maybe so.

> On my first passing of Rafal's email, it seemed to me that 
> the ensemble that he was describing was merely explanatory, and not 
> necessitating MWI or even itself -- merely as a way to describe data 
> structs in the world that we experience on a more abstract level.

Yes.

> [Lee asked Rafal]
>> Now on your usage of words, you and I and all the Lee's who
>> were/are fighting in the Second World War, are simply a part
>> of the great Tree of Me. An immediate difficulty you might want
>> to address is, "Does the tree of Lee overlap with the tree of
>> Rafal?"  If not, why not?  My own "fuzzy spheres" do allow
>> for overlap at their extreme edges.
> 
> Are not all things, somehow related, if not physically then at least in 
> our minds?

Come again?  How is the most southern orange on the most southern
orange tree in Florida related to President McKinley's assassin?
I'm surely the first person in history to inquire about that
ridiculous "relationship".

> Somebody might reply to this saying "try to find a 
> correlation between X and Y" and that would only serve to show that 
> somebody has in fact made that correlation, and the more that people 
> read that email, the more 'real' it is becoming (I do not mean to say 
> that popular approval increases the realness, merely that the content 
> is diffused over the surface area of the local reality, so it is 
> becoming more than the 'nothing' that the original emailer was hoping 
> to select for).

Then the relationship between the Holy Trinity and God must be
pretty damn real by now.

Thanks for the mental workout, (I think).  :-)

Lee