Sometimes I can't help but ponder this whole multiple universe issue. Maybe it's because I'm a philosopher that I'm attracted to this juicy piece of Science bait -- if talk of multiple universes really is Science, which has been at some controversy. There are two things that I often wonder about. The first is the role that multiverses are suppose to play in cosmological theories, which seems problematic to me. The second is the too-explosive range of universes that supposedly spring into subsistence when available quantum states are utilized as ways of mapping the possibilities from the immediate moment forward.
IAt first glance, it seems that were there a multiverse, it would not be observable, since any such other components of the multiverse are being created outside of our big bang light sphere. Indeed, every other component universe of the multiverse would have the same problem, that of not being able to observe anything outside it's own big bang light sphere.
"Look," someone might counter, "direct observation is not needed to establish or give evidence for the multiverse, for there are other, indirect ways to justify it. This theory has survived falsification and there are no other contenders for anything better." The idea here is that if some physics theory predicts an observational consequence of a multiverse, and we don't see that consequence, then the multiverse theory (or that particular type of multiverse theory) would be defeated.
Put differently, with a bit more detail, suppose somebody claims, that some observation set (+O1) entails a theory of an unobservable multiverse (-T2) And this theory of an unobservable multiverse, entails some other set of observational evidence (+O3). We then note that +O1 should always entail an observational correlation to +O3. So the scientific matter would stand as follows:
+O1 --> -T2
-T2 --> +O3
So,
+O1 --> +O3
If one noted the presence of +O1, but the absence of +O3, then that would be good Popperian[1] defeating evidence for -T2. But the harder problem is where we are now: Where we have +O1 and +O3 kinds of phenomena (from quantum theory, apparently) but the status of darling theory -T2 (the multiverse claim) is worrisome.
Suppose there is some other kind of unobservable theory, maybe of another kind of multiverse with vibrating strings, or maybe of super-powerful beings, or even of a supernatural being which holds the order of space and time together in the way we observe it. Indeed, perhaps there are several of these types of theories floating around. Call any one of them -Tn . (By analogy, suppose you had a jar of colored marbles, M. You close your eyes and pull out one of a certain color, which your near-by friend notes to himself as '+M_red'. But for your part, you can only say, '-M_n' to represent a marble whose color you don't know about.)
So the scientific matter would stand as follows:
+O1 --> -Tn
-Tn --> +O3
So,
+O1 --> +O3
If such a theory did not, up to the most recent testing, show any exception of correlation of +O1 to +O3, does that make it a good theory? There are an infinite number of -Tn -type of theories one could posit that are consistent with the noted observations. That's very worrisome. It looks like one is using speculative, metaphysical linkage to build a cosmological, scientific theory. But if intelligent design posits in biology have taught us anything, this all seems the wrong way to go, for whether the linkage is of a personal metaphysical object (God) or an impersonal metaphysical object (a non-observable super-structure), one leaves the realm of science as it's been practiced since Galileo.
Admittedly, I do think advocates of a multiverse theory can get around the above complaint; since posited, apparently unobservable entities sometimes turn out to be observable after all, as the history of the concept of 'gene' has shown. So my real problem is that cosmological positions about about a multiverse are derived from previously held commitments in quantum theory, and quantum theory is probably the most intensely tested, most reliable scientific theory known to science. Thus, what really tempts me to multiverse belief comes from the bottom-up issues of quantum theory, not from the top-down issues of cosmology. So let me now turn to this side of the issue.
IIThe first step that seems to draw me in is what has drawn many in: the unrivaled empirical success of quantum mechanics. Many scientists intimately involved in quantum mechanics think it's more than just a handy mathematical model for organizing data; instead, they have the gaul to say it's "true", even if they often admit they don't understand what it all means. As Michio Kaku writes, “It is often stated that of all the theories proposed in this century, the silliest is quantum theory. In fact, some say that the only thing that quantum theory has going for it is that it is unquestionably correct.”
The second step that makes me muse all metaphysical about multiverse claims is the on-going engineering attempts at quantum computing. Whole governments and academic institutions are pumping big dollars into a form of computation that can use peculiar quantum mechanical phenomena like superposition and entanglement as a way of manipulating data, first by representing the data in parallel ways, and then by operating on all of those representations. But to harken back to the first step above, there are quantum mechanical phenomena, because the world itself has a real structure -- namely, a quantum structure. Quantum computing harness a lot of stuff going on in parallel, specifically bit storage and bit operations. But these parallel activities are supposedly not going on "here" -- so just where are they going on?
The third step which pulls at me is where I make a simple deduction from the first two temptations. We talk about our 'Universe', which is supposed to be the One, the Everything. And these quantum phenomena used in quantum computation are happening at some particular place, in somebody's lab. But these computations, beyond the observed phenomenon, are taking account of several different states which are "not" representative of some local lab's state of affairs. So they represent states of affairs that are not local, but removed from the local. What is the ontological status, the nature of the reality of this non-local place?
And now the mind-thrust begins. Apparently, the states represented by these quantum representations are states of 'possibilia', affairs that are possible in terms of what's happening now, but gain something extra -- call it 'subsistence' -- upon being stored as data. This is akin to the celebrated Schrödinger's cat issue, where the cat has no actual status until one looks at it, or until some arbitrary event collapses the cat's dual-subsistence into some non-arbitrary state of affairs plucked from the set of 'possibilia' --i.e., the cat, as both alive and dead, moves from subsistence into existence. So, just as there is an actual cat that enters a non-actual, dual-subsistence cat state for a bit; likewise, there are quantum phenomena that enter a non-actual state for a bit, and then -- well, it's just more than I really want to think about; but, I can't seem to avoid such thoughts. People are always writing about it, bringing it up in conversations, occasionally outright asking me about it -- even though I really wish they wouldn't.
Anyway, to summarize -- there's the way things are, and the way things might be, and the "might be's" are somehow accessible from the way things are in quantum computing. But a moment's thought makes one realize that there are an infinity of the way things 'might be' from the way things 'are.' At this moment I could utter, by voice, any given number. I might say "One!" at the top of my voice. Or I might whisper "Two-thousand eight -hundred and fifty-two to the 39th power." Short of having to just take the few moments to utter the very sounds it takes to identify the arbitrary number in question, there are an infinity of numbers I can select from. I could even partition my arbitrary utterances into a structure: I could resolve beforehand to utter only odd numbers, or only even numbers, or only numbers divisible by five --- it doesn't matter! I still get an infinity of choices within whatever pet basis criteria for utterance I happen to choose beforehand. This must mean that there are an infinity of parallel states of affairs that either could spring off, or do spring off from this very moment, from this tiny choice of what I may utter. Add all the other utterers available, and the possibilities loom ghastly large. What am I supposed to think of this? How am I supposed to think of this?
Maybe the latter question is at least tractable. Take a slightly different angle: why utter elements from infinite, structured sets of numbers? 'Too dang many chickens in that coop! Instead, in order to narrow things down, I could utter collections of formula from algebra: "1< y < 20", "x < y*3 < z." Hell, that's some pretty talk right there! I like this game! Again, how about this one: "Let z=x and x<7; and, x is either 2, 3 or 4; moreover, stipulate that x is not 4." Now I've thrown in some logic operations as well! Call this 'f' for fancy formula utterance. And for good measure let's call the set of answers for f (if there are any answers) by the capital letter 'Z'.
Behold -- my utterance f hangs in the air, held temporarily by my (and by any hearer's) short term memory, or maybe it would hang a bit longer if written on a chalkboard, or stored in a computer, or chiseled in granite -- whatever; it's stored someplace in some physical medium, where I, or somebody, can later retrieve it.
Certain strange ideas can arise here. Suppose you ask me how much I'm going to spend on coffee this morning. On the one hand, I could say, "Why, only as much as I have in my wallet!" But there is an exact amount in my wallet, I just happen to be ignorant of how much that amount is. On the other hand, and here's where the strangeness begins, I could say, "Why, f!" (And then I'd jump up and write the formula for f on the chalkboard so you're not clueless.) You'll grant me that there are different equivalent ways to write f on the chalkboard.
I could write the original locution:
f: "Let z=x and x<7; and, x is either 2, 3 or 4; moreover, stipulate that x is not 4."
Or, maybe this:
f1: "Let z=x+0 and x<7; and, x is either 2, 3 or 4; moreover, stipulate that x is not 4."
Or, though odd and extraneous, this:
f2: " Let z=x+1-1 and x+1-1<7; and, x+1-1 is either 2, 3 or 4; moreover, stipulate that x+1-1 is not 4."
The first, second, and third versions all have different information in them, a different collection of symbols, but they all yield the same list of answers in Z -- namely, { 2 , 3 }. (So, it's turned out that the variable z could be a legitimate answer for f in more than one way. So that's why we need not just 'z', but 'Z' to track the list of all legitimate answers.) When you ask me the coffee question, formula f is somehow identified as the answer, even if (chatty guy that I am) I answer your question in two or three different, but synonymous ways, likeunto f1 and f2 above.
Alas, now I'm forced to introduce yet another capital letter, 'F', to account for all the ways that I could synonymously utter (e.g., speak, or maybe chalk-down) f as an answer to your coffee question. A moment's thought shows there's an infinite number of elements in the set F. (I could also add zero, or two zeros, or three; or, I could add one, and then subtract it, or two, and then subtract it, or three...)
And now for further weirdness. As earlier, the states represented by Z are states of possibilia, affairs that are possible in terms of what's happening now (I might pay $2; I might pay $3 for coffee), but these 'possibilia' have gained subsistence upon being stored as data, the job that f is doing in our conversation. Restated, there's the way things are, and the way things might be, Z, and the "might be's" { 2, 3 } are somehow accessible from the way things are at the moment of conversation. So too are the states represented by F, and its "might be's", affairs that are possible in terms of what's happening now (I might restate f one way, another way, etc.), but these "might be's" { f, f1, f2, f3, ... fn } have likewise gained their own subsistence at the moment of conversation.
But now there's yet a further explosion on the already ghastly number of multiverse possibilia branching out from the moment of conversation. Granted, by uttering any synonymous phrase f within F, I've constrained my money commitment to only one of two expenditures, $2, or $3; but, that does not mean there is only two possibilia branching out in the multiverse. Why? Well, since there are an infinity of ways of communicating f (an infinite number of elements in F), there are a concomitant infinite number of subsisting possibilia too. An infinite number of me's, and an infinite number of you's out there waiting with baited breath for me to grab onto the horn of which dollar commitment I'll take as regards to coffee expenditures. Yet this infinity arises not because there are an infinite number of dollar options, but because there's an infinite number of ways of stating even a limited number of dollar options. Afterall, even if I'd just said "I'll spend two dollars," where Z has now only a single element { 2 }, F would still have it's infinite number of elements.
There's nothing in the laws of physical possibility, much less logical possibility, which constrain me to state f in one way rather than another. But this means there is this infinity of duplicate universes, this grand waste of me's and you's where there would be only a single, syntactic shuffle, a trade-off of a couple of extraneous +1's/-1's for a couple of extraneous +2's/-2's within F that separates whole branches or collections of branches within the multiverse. What's the lesson of that?
I will tell you. The multiverse is wasteful. Occam's razor counsels us not to multiply entities beyond necessity; but Quantum's razor provides us with the ugliest possible corollary to that claim: beyond entities there's the necessity of multiplication.
O.
REFERENCES[Image] Nature.com (Accessed 1/2/2009)
[1] A quick over-view of Karl Popper's falsification procedure can be found by Ralph E. Kenyon, Jr., "
Popper's Philosophy of Science" (Accessed 1/2/2009)
[ * ] I thought my first post of 2009 should be something both philosophically and scientifically oriented, since that's what the blog is supposed to be about. Yes, I'll admit I wander from that ideal now and then. And I can't believe I'm still piling time into this (so-called) little side venture of going on four years. The problem is that Google tells me that people from all over the world drop in on this blog, and about a third of them are returning visitors, so it always feels worth it to write something that people are going to read (or listen to).
Labels: Logic, metaphysics, Multiverse, Philosophy of Physics, Quantum, Quantum's razor
