Saturday, May 26, 2007

More Weird Ideas

Speaking of other worlds, it occurs to me that since I’ve assumed the falsity of the many worlds interpretation (MWI) of quantum mechanics in my forthcoming paper, hence I ought to develop something more like an argument against it—rather than the vague antipathy towards it that I've expressed at On Philosophy (for many-minds) and Mormon Metaphysics (against MWI). To begin with, either materialism is true or it ain’t; and if it is then I’m essentially my brain. According to MWI, I’d be continually budding into infinitely many others who had (until then) been me, which is what I intuitively reject. Maybe I can’t say for sure that that isn’t what it’s like to be me, because I can’t really imagine what that would be like, but prima facie that contradicts what I know for sure about myself (via my direct acquaintance with myself). And of course, were materialism false, the mind-brain interaction would need to be understood, and so in that case MWI would be much less attractive anyway. Not much of an argument so far, so I guess I ought to try to imagine what it would be like to be constantly splitting into infinitely many people... (Maybe not!)

14 comments:

Peter said...

I am NOT in favor of the many worlds interpretation, I am for the many-minds interpretation. In the many minds interpretation there is only one world, but its quantum state is very complex

Enigman said...

Sorry, I've changed that now. I was assuming that each set of minds would correspond to an actual world. I wonder what you say about the world before minds evolved, when presumably (going by working science) the physical processes were nonetheless quantum mechanial (?)

Peter said...

Unlike collapse theories, in no-collapse theories minds play no special role, being purely physical objects like eveything else. Thus the world would be basically the same. Many worlds and many minds are simply theories as to why collapse seems to occur to observers, they don't give observers any special role.

Enigman said...

Even so materialists have stories to tell of how life (and then minds) evolved, stories set in a world like the world that we observe around us, rather than your complex-state world (?)

Peter said...

The world we see around us is one part of the complex state of world, thus a true description of it is a true description of part of the whole complex state. This is why empirical science is still justified under such an intereprtation of quantum mechnics, which may be less than you can say for interpretations like the bare theory.

Enigman said...

But then the import of your distinction between many worlds and many minds is still unclear to me. E.g. presumably another part of the complex state is a spatio-temporal region (as the classical Universe is) in which the particles (so to speak) corresponding to our Solar System are all inside a black hole (this many years after the Big Bang, for them, although presumably not at this time, given their location). But prima facie that black hole being part of this world is like Neptune being the same world as this Earth (originating in the same gas cloud), or Africa being the same continent as America (originating in Pangaea). Prima facie 'many worlds' is not even a particularly inappropriate name for your interpretation.

Enigman said...

(Incidentally I've just noticed a recent post against many worlds at Quantum Quandries, whence this memo-comment.)

Peter said...

I don't make up the names, I just use them. in any case the distinction between many worlds and many minds is that in many worlds the worlds really are splitting off, which raises possible problems with a physically preferred basis and compatability with SR given how fast the splitting takes place. In many minds the splitting of many worlds is only apparent, there is only one world. Basically the differences are mathematical and in interpreting what the mathematics means. Note, just because you can't precieve the effects of the other parts of the complex world don't mean that they are part of another world, that would be like arguing that objects farther away than light could have travelled for the entire age of the universe are in a different universe because we can't interact with them (note: they are actually still in our universe). Also you could take in principle a complicated kind of measurement to interact with them. David Lewis wrote about the possibility of doing this, although he was working in the many worlds interpretation; the possibility of such interactions occuring is one more reason to think that many worlds is a bad interpretation.

Peter said...

Further note: I have no idea why, but in the post you link to when the author says "many worlds" he really means "the bare theory". I have no idea why he keeps calling "the bare theory" "many worlds", unless he refers to all no-collapse interpretations as "many worlds". The reason I say that he must really mean "the bare theory" is because his argument is that it doesn't give observer definite results to their observations. While the bare theory says that observers don't get definite results they do get definite results in many worlds and many minds.

Enigman said...

Many thanks for clarifying that for me (incidentally I've just noticed that I previously said 'inappropriate' when I meant 'appropriate'). I don't know about Matt, but when I read about QM (25 years ago) I thought of the bare theory as giving us (short-term) future probabilities from given initial conditions (related to actual measurements).

Enigman said...

A remaining obscurity is, does many minds need a relational view of time? I ask because of the aforementioned black hole. If so, then the hard (for a materialist) problem of consciousness would seem to be harder, for why should minds (that seem to themselves to be temporally persisting) exist, but not other sorts of subjectivities (associated with other parts of the complex world)? (If so then maybe 'many paraminds' would be a more accurate name:)

Peter said...

Here is a description of the bare theory: http://plato.stanford.edu/entries/qm-everett/ (written by Dr. Barrett), although there he only considers the dualistic version of many minds. In any case minds exist because the part of the quantum state that they supervene on has the right functional properties, other sorts of subjectivities aren't present because the right sorts of functional properties aren't present. This is the same reason why we deny that rocks are conscious.

Enigman said...

I agree that that is why we deny that rocks are conscious, but other well-known aspects of our minds may lead us similarly to reject your epiphenomenalism. A fundamental problem with many minds is, I think, that even if I suppose that you are right (and that the scientific evidence will increasingly indicate as much), then I would consequently know that there was no good reason for my actually adopting your view. In that sense, your interpretation is self-undermining. Although I have intuitions that truth is important for its own sake, which I would keep even after accepting your view, I also have intuitions about time and choice, about myself and other people. Were I trying to see the falsity of so many of my basic intuitions, I would have to wonder about whether the indicated truth of a belief was really a good reason for me (as a part of a deterministic world) to adopt it.

Enigman said...

But regarding the indicated truth of your view, is there any reason why only the functional properties associated with our minds could give rise to subjectivities (was there a sharp cut-off in our evolution?)? Furthermore if space-time is relational, why should a sufficiently large rock (or gas cloud etc.) instantiating, as one of its many substructures, those same functional properties (maybe spatially extended where ours are temporally extended) not be associated with a subjectivity just like ours (for all that it would not seem like a mind to us)?