You are offered a deal in which you are asked to flip a coin ten times. If any one of the flips comes up tails, you are swiftly and painlessly killed. If it comes up heads ten times in a row, you are given a banana. Do you take the deal?
For the purposes of this thought experiment, we may assume it is a perfectly fair coin, and that you like bananas, although not any more so than would generally be considered healthy. We may also assume for simplicity that your life or death is of absolutely no consequence to anyone but yourself: you live in secret on a deserted island, isolated from contact with the outside world, where you have everything you need other than bananas. We may finally assume that we know for certainty that there is no afterlife; upon death, you simply cease to exist in any form. So, there is an approximately 99.9% chance that you will be dead, which by hypothesis implies that you will feel no regrets or feelings of disappointment. And if you survive, you get a banana. What do you think?
Now change the experiment a little. Instead of flipping a coin, you measure the x-component of the spin of an electron that has been prepared in an eigenstate of the y-component of the spin; according to the rules of quantum mechanics, there is an even chance that you will measure the x-component of the spin to be up or down. You do this ten times, with ten different electrons, and are offered the same wager as before, with spin-up playing the role of “heads” for the coin. The only difference is that, instead of a classical probability, we are dealing with branching/collapsing wavefunctions. I.e., if you believe in something like the many-worlds interpretation of quantum mechanics, there will always be a branch of the wavefunction of the universe in which you continue to exist and now have a banana. Do you take the deal?
A fairly interesting treatment of this is ‘Meanwhile’, an interactive webcomic by Jason Shiga. (The guy also does a number of other geeky comics. His site is pretty good fun. At least, for me.)
In case the interface confuses you, you basically follow the story along the tube, taking branches as choices. When a tube goes off a page, click the tab where it leaves, and then continue on the page you arrive at from exactly the same point where the previous tab was.
Feloneouscat:”there can be many pasts” Maybe this meant what I said “the half-life of proton is actually 1s.” Many comments to read…
truth machine:”an experiment doesn’t alter its actual outcome.” Sorry, meaning is? Right. But the experiment was performed, after assuming MW interpretation is true.
Logically I would of course refuse the deal. If (a) MWI is correct then, as has already been pointed out, in some other Universe I have already taken the deal and some me somewhere has gotten a banana. In fact an infinite number of me, since this deal has been offered to me an infinite number of times. If (b) MWI is not correct and I lose, then I’m dead and perhaps it’s the experimentalist side of me but there are many things besides bananas which I enjoy in life (even on the hypothetical island)– thinking about ideas such as MWI, for example. So I can only lose by taking the deal.
As for the philosophical conundrum of how I plan for my future self (in this, the only Universe of which I have an experience or memory) again it’s simple — there are again two possible options: either it’s all an illusion (e.g the example above where I am destroyed and recreated each night; or pesky transporter operator) in which case nothing I do or don’t do will make any difference or I can actively work to impact the relative comfort of my future self by going to the store and buying a banana for my future self to enjoy in the morning (modulo interference with my plans by a hurricane or a banana loving partner who absconds with my fruit in the middle of the night). If it’s all an illusion, my trip to store is irrelevant. If not, I might as well get off the couch and buy the stupid banana if I want breakfast in the morning.
My apologies to St. Augustine for essentially rephrasing his arguments.
Finally, I’m not sure I understand the arguments for MWI. In order for this interpretation to make any sense, it has to assume a complete and consistent theory at the most fundamental level — which we obviously don’t yet have (quantum gravity in particular). We (scientists, philosophers, humans) have a tendency to extrapolate from our current (imperfect) understanding of something, forgetting that what we don’t yet know can change everything. The ether made sense based on what we knew about wave propagation. Extending what we understand about QM is a lot of fun, but probably extremely premature. Certainly not worth a banana.
Kevin writes:
A loss to whom? If I leave a room, the lack of a me in the room is no loss to me. When talking about things like loss, it’s vital to establish the subject. Failing to do so leads to such absurdities as debates over “what is the purpose of life”, which verges on grammatical incoherence, much like asking “what is the expectation of health” as if expectations and health were universals, needing no specification of subject or object.
cat writes:
I don’t know about you, but I’m speaking plain English. If I mix two chemicals after assuming that George Bush will be impeached, I’ll get the same result as if I had instead assumed that aliens will land on Earth next week. Making assumptions, which is about our mental states (which translates into physical states of our brains) doesn’t affect the outcome of the experiments we perform (it may affect which experiments we choose to perform, but that’s a different matter).
To Fzplus: ‘Meanwhile’ is fun — thanks!
P.S.
Cat wrote
Perhaps it would be easier to discern my meaning if you didn’t chop off the front of my sentence: “How we interpret an experiment doesn’t alter its actual outcome.”
macho writes:
That example has nothing to do with illusion — as I noted, your body state is constantly changing; the “you” that wakes up tomorrow is not the “you” that goes to sleep, given the basic facts of physics and biology; the example was just to make the change more radical so as to bring the issue into focus. Your thinking here is riddled with false dichotomies. For instance,
Whether or not I am some sort of agent of libertarian free will, going to the store and buying a banana makes a banana available to me in the morning whereas not doing so doesn’t — it makes a difference whether I do so, even if I am a deterministic machine (and thus which of the different outcomes will obtain is in some sense fixed). The only rational way to approach this is to recognize both that we are machines and that we are intentional agents — that these are different levels of description for the same set of phenomena. Daniel Dennett has explored this at length during his career, and his latest book “Freedom Evolves” is recommended to anyone who actually wants to understand this stuff (as opposed to being free to make whatever claim pops into ones head on the subject).
truth machine writes:
Talk about your false dichotomies, sheesh.
Your philosophy has to remain current with experimentation, in order for it to be correct mathematically?
Have a Happy New Year
More here, and in English.
“Talk about your false dichotomies, sheesh.”
Of course one can both want to understand things and want to say whatever pops into their head, but that rather misses the point. Sheesh indeed.
“Your philosophy has to remain current with experimentation, in order for it to be correct mathematically?”
Why do you put question marks at the ends of statements?
If something is inconsistent with experimentation, it is incorrect empirically, not mathematically. In any case, MWI is not inconsistent with experimentation.
Why do you put question marks at the ends of statements?
Because this is new territory for me, and I am unsteady like a young pup trying to find it’s legs.
If something is inconsistent with experimentation, it is incorrect empirically, not mathematically.
Logic forming is also new territory.
If we were to talk and express ourselves in ways that were held close to current trends and models of thinking and topic here previously, then the logic would closely follow the math?
If you didn’t, you would then be inconsistant not only empirically, but also mathematically as well?
I am reminded of the roads leading to String/M theory, that is supposed to be very abstract and not in touch with reality.
If I express a new model for consideration, then it would have to be empirically and mathematically consistent?
How can you move into new territories without having some basis from which to work? “Shoulders of Giants” 🙂 “All those who came before us.” Now, we see where it is going 🙂
I apologize for my continued persistance.
I am “trying to learn” to see how a teacher would continue to work(has been updated) to improve the philosophical process.
Introduction of “new Maths”. New experiments. How would these “by themself” change the philosophical process? Would they?
truth machine writes:
The loss is to the universe without me, not to me. You see, I’m so magnanimous, I can’t bear the thought of universes without me.
A room that you have left keenly feels the loss.
If all this talk of bananas and star-trek tansporters is muddying the waters with too much ‘philosophy’, here is a nice simple science question. I have a fabulous new theory of quantum gravity. It unifies the forces, resolves cosmological singularities, and predicts the fine structure and other dimensionless constants to 5 digit precision. It makes stunning predictions for LHC physics, all of which are confirmed triumphantly. But there is one catch: it inevitably, unavoidably, includes a vacuum state of lower energy than our own, to which our universe can decay. The (quantum!) tunneling rate is such that once per year per cubic lightyear, a true-vacuum bubble will form and expand at the speed of light. The energy density in the bubble wall will instantly destroy everything in it’s path, including people like us.
Now, is my theory ruled out? In the Copenhagen interpretation (in a finite universe; see below), surely: the chance of us surviving this long would be infinitesimal. In Many Worlds, I would say maybe not: the seemingly problematic are no cause for concern since they are perfectly unobservable; perhaps in some ‘other universe’ someone just got obliterated by a bubble wall passing through this room, but who cares? It was not us. Our history of observations is perfectly consistent with the theory.
To be more provocative: in my earlier post I argued that I could not see any essential difference between many worlds and an infinite universe. So, is my super-duper theory viable in an infinite universe but not in a finite one (or sufficiently small size)?
To be even more provocative: does the existence of this highly compelling theory, which is viable only in the MWI (or perhaps infinite universe), give evidence for the MWI, which is otherwise just ‘philosophically’ different from Copenhagen, or for an infinite universe, which is only ‘philosophical’ since beyond our horizon?
Anthony (#14): “..the many-worlds interpretation is just nuts..” .
Maybe, as it now stands, but give it a little time to evolve.
_________
Macho (#53) “We.. have a tendency to extrapolate from our current (imperfect) understanding of something, forgetting that what we don’t know yet can change everything.” .
So true, so true – but, by definition, we have nothing other than our current understanding to extrapolate from. Extrapolation good. Extrapolation is a kind of testing; the extrapolated POV can put an hypothesis in a new and often informative context and can provide credibility to the hypothesis or debunk the hypothesis at an early stage. MWI invites extraordinary extrapolation which may be especially vulnerable to your “what we don’t know yet”. What we don’t know yet might, on the other hand, make current extrapolations look timid and tentative. (IMO)
Anthony A., this is an interesting example, if this scenario materializes all we learn is that events with infinitesimal probabilities (according to the otherwise compelling theory) do seem to happen. One can draw all kinds of conclusions based on that, including the MWI or the infinite universe, or divine intervention, or simply that the theory is wrong. I am not sure what would the consensus be, but personally I would need more than one piece of evidence to postulate such an enormous redundancy.
But, it seems to me that barring the occurence of this scenario, the hypothesis that events with infinitesimal probabilities happen is already falsified. We don’t see our world to be random, we do see order wherever we look. If such events exist why would they be restricted to one clean signal like in your scenario, why don’t we see miracles happening all around us?
If such events exist why would they be restricted to one clean signal like in your scenario, why don’t we see miracles happening all around us?
Probabilities are independent. That one unlikely thing happens to happen has no bearing on anything else.
Yes Aaron, but the new element in this game is the “infinity” , that makes very unlikely events possible to begin with, then what distinguish an unlikely event from ten of them? there is no scale in the problem.
The more I think about this the more reasons I find that Tegmark was wrong. Consider this modification of the suicide experiment. Suppose that instead of being killed you are made unconscious for a limited time. Then, according to Tegmark’s reasoning the MWI would predict that you find yourself in the conscious branch just after the experiment with probability 1.
So, one really has to look at the whole multiverse and consider the probability distribution over the set of all possible versions of the observer. Tegmark’s argument makes the hidden assumption that the observer never suffers memory loss or always remains conscious. This is clearly not true, MWI or no MWI.
The reason why you should not take the deal, even if you believe in the MWI, is because the states in which you gain have a very low probability. You don’t change the probability by killing yourself in the wrong branches. There doesn’t exist a ”law of conservation of memory” in physics which guarantees that you will always experience a time evolved successor state.
sisyphus: I agree completely — extrapolations are essential to testing our current models and theories and pushing our understanding to a deeper level. As you point out, our current understanding of general relativity is much wilder than 18th century speculations, based on Newtonian gravity, on the existence of a star so massive that nothing could escape its gravitational field. But the point is that if you already know that your theory is incomplete, betting your life on it is foolish.
Is no one else bothered by the consistent use of “belief” in MWI? It may or may not be correct, but I neither believe nor disbelieve in it. Phrased this way the quantum suicide experiment smells very strongly of koolaid, not science.
Macho: As I indicate in #12 I wouldn’t take the bet either. Sean says (#15) that the thought experiment source is philosophers, not scientists.
I have a lot of problems with MWI as it is at the moment; what bothers me most is the matter of the location of the experience of being. I’m going to review the material I have on MWI when I have some free time – maybe in a couple of weeks.
I hope that MWI succeeds; it has astounding implications.
Regards
One has to re-read the original thought experiment a number of times?
Sean amazing experiment, but lets say that Iam undecided about the actual experiment set-up?
1)Where is the “Banana” before the experiment starts?..what proof are you going to provide to any person willing to take this challenge, that Banana’s actually exist!
2)If you provide a satisfactory explanation that as a reward, “banana’s” do exist, and thus the experiment has a worthwhile function.
3)”If you are isolated from everything”, then obvious this include’s Banana’s, the fact that you have “everything” except Banana’s is no justification of instigating the “thought” experiment, why take a risk of something you can do without.
4)The paramiter of “heads/tails” are intricately linked to a Hidden/Unknown parimiter of future event “outcomes”.
If you toss the coin (for simplicity before collaborating the spin of electron!), and get heads for 5 throws of the dice, each outcome is a ‘future’ event reward. On the sixth throw you come up tails, you are killed. This is also a ‘future’ time ordered event outcome, or is it?
There is a small chance the event of you being killed throwing a tails, (which has its own wavefunction)..occuring at the first throw?..thus how could you have thrown 5 straight Heads?..then a tails, when there was an initial probability that you may have been exterminated after the very first throw?
Past Present and Future, are Time ordered events which dictate a before and after.
6)There is no known way to express the spin state of Electrons as in the “Present”.
Every single measure of an Electrons spin, carries a very HIGH Probability that the Electron does not have a time-stamp, pertaining to a “PRESENT-TIME”.
I believe Weinburg and Feynman stated that there is only one electron (or chance ther-of?), and it is NEVER located in the present-time. It has always either existed in a PAST-TIME, or it will surely exist in a FUTURE-TIME, but never,never..found to be in the Present.
So now we have the two paramiters of assosciated spin, up and down, or + or -.
To make the experiment worthy for a satisfactory out-come, we now have to make a time-ordered calibration of Time,this is to say:
Do the experiment whereby ‘spin-up +’ is a “future” (projected-unknown) outcome, and ‘spin-down -‘ is a past definate (absolute/occurred) event.
All possible combinations (+/-) have to be considered, even events where, spin-up/heads, occured in a “Future-tense”, and are determining the choice of “Present-time” limitations of experiments, by ensuring that we can NEVER know if Electrons are ones that have tunneled from the future to the past, or from the Past to the future.
As far as I know, the Electron is still fooling us?
Think of a man sitting on a serene beach, suddenly Banana’s start appearing all around him, filling the surrounding beach and his locality.
Q:Does he get up and move elsewhere, or does he hold his ground and trust his mental ability to ignore “unreal” events?
Paul:
No! What happens next is that the alarm goes off and he wakes up. 🙂