I got this letter in the mail the other day:
I Don’t know if you Exist But I Do! I bo not Agree with your Articl and I Do not Beleave that “MOMBO-JOMBO” if you do … Well! it’s Disturbing thought But I know How to Deal with it! I will Not let the Wolb Disiper under My Nose But if you Do I cant say I’m sorry!
Sincerely
a ten year old who knows a little more than some Pepeol!
George Wing
ps. some peopl Have a little to Much time.
In response, of course, to the NYT story about Boltzmann’s Brain. George’s father Michael, a high-school science teacher, was moved to send it along (and gave me permission to post it), suggesting that “maybe it is really a Boltzmann brain speaking.”
To which I can only respond: awesome. A fourth-grader reads an article in the Science Times, and is so moved by outrage that he pens a stern missive to the scientists quoted? It’s not very often that you have a chance to inspire a young mind like that, even if you do inspire him to berate you.
Of course, George did fall into a slight trap with respect to the logic underlying the article. But that’s okay — he’s only ten years old, and there are plenty of grownups with Ph.D.’s in physics who fell into the same trap! The trap is to imagine, despite explicit disclaimers to the contrary, that the Boltzmann’s Brain argument goes something like this:
Certain cosmological scenarios predict that it’s more likely for a brain like yours or mine to arise as a random fluctuation, rather than through orderly evolution.
Isn’t that cool????
That’s really not the argument that anyone is trying to make. Rather, it goes like this:
Certain cosmological scenarios predict that it’s more likely for a brain like yours or mine to arise as a random fluctuation, rather than through orderly evolution.
Our brains aren’t like that.
Therefore, those scenarios are not correct.
It’s kind of an old-fashioned argument. Take a theory, use it to make a prediction, the prediction isn’t correct, and therefore the theory has been falsified! Rubs a lot of people the wrong way, but it works for me.
Other critics are uncharitable for different reasons. For example Don Walton, founder and president of Time For Truth Ministeries:
I believe the accusation leveled against the Apostle Paul by Festus in Acts 26:24 — “much learning is making you mad” — is most apropos for today’s cosmologists.
Hey, question my existence and suggest that I have too much time on my hands, fine — I can deal with that. But comparing me to Saint Paul? That is a low blow, sir. And somewhat unprecedented.
When you’re ten years old, you don’t have to be right — you should be curious and passionate, and George definitely is on the right track. I look forward to recruiting him to grad school some day. For the grownups I have less hope.
That letter is just adorable.
You wrote:
that the Boltzmann’s Brain argument goes something like this:
* Certain cosmological scenarios predict that it’s more likely for a brain like yours or mine to arise as a random fluctuation, rather than through orderly evolution.
* Isn’t that cool????
That’s really not the argument that anyone is trying to make. Rather, it goes like this:
* Certain cosmological scenarios predict that it’s more likely for a brain like yours or mine to arise as a random fluctuation, rather than through orderly evolution.
* Our brains aren’t like that.
* Therefore, those scenarios are not correct.
Question – does the Boltzmann’s Brain hypothesis have any limitation on the epoch of the scenario, that is, does an argument of this sort fall within the scope of the BB hypothesis?
* Certain cosmological scenarios predict that it’s more likely for a brain like yours or mine to arise as a result of a random fluctuation in which brains evolve in ways that are either identical to or remarkably similar to the way we believe our brains evolve, and we cannot at this time determine whether the evolutionary path is the one we believe or an alternate path.
*We know what our brains are like with a precision far, far greater than we know our brains’ evolutionary path.
*Therefore we have no way of using this hypothesis to determine much of anything relevant to branes.
Isn’t there a hidden assumption here that we are a random sample from the space of observers? But since we aren’t a random sample, the conclusion doesn’t follow. It strikes me as being like someone with a 210 IQ saying “if IQ is distributed normally, then I am incredibly unlikely to exist. But I do, therefore IQ is not normally distributed.”
Sean,
I haven’t heard of any grown-up Ph.D. physicists who read the NYT article and didn’t understand that the goal of the active field of Boltzmann Brain studies is to explain why we don’t see them. On the other hand, from what I hear, a very large number of physics Ph.D.s wish the NYT Science Times was not covering the spectacle of some of their colleagues arguing over issues such as whether consciousness is relevant for counting observers in the multiverse. Many would agree with the recent characterization of this by one well-known science journalist: high IQ pathology.
You passed over ME, and now you want to recruit a dyslexic 5th-grader who has yet to learn the basic rules of capitalization, spelling, and syntax? Talk about disembodied brains!
Or, “Brians”. You misread Don Walton, founder and president of Time For Truth Ministeries, who wrote:
“These entities are called ‘Boltzmann Brians’ and the supposed soundness of Boltzmann’s argument is referred to by today’s cosmologists as the ‘Boltzmann Brian Problem.'”
For those without a proper understanding of the historical context, Boltzmann’s Brian was Brian Scheutz, a cheeky graduate student who supplied Dr. Boltzmann with many of his best ideas. Boltzmann’s argument was that if he had recruited dyslexic 5th graders who had yet to learn the basic rules of capitalization, spelling, and syntax then he would still have to put up with the cheekiness but wouldn’t have had the ideas. Brian Scheutz obtained his post-graduate degree and died in 1925, a 30-year veteran taxi driver honored for his pioneering the use of horseless carriages in the taxi business.
* Certain cosmological scenarios predict that it’s more likely for a brain like yours or mine to arise as a random fluctuation, rather than through orderly evolution.
* Our brains aren’t like that.
* Therefore, those scenarios are not correct.
I have an issue with the second point, namely: how do we know? I understand (I think) the argument of Boltzmann’s Brain. If Boltzmann’s universe was true and the universe spends most of its time in a high entropy state and only randomly fluctuates now and then, small fluctuations will be immensely more probable than large ones. These small fluctuations would therefore be much more likely to give rise to brains than to full universes with big bangs, and therefore assuming our universe is a huge entropic dip is a problematic assumption. The problem here is that the question then becomes like the old philosophical question of the brain in a vat. How do we know the universe exists outside of ourselves? We have Decartes’s Cogito Ergo Sum but after that we have no actual knowledge. Is there any way to refute the claim that the universe doe not exist, merely my “brain” (which need not resemble what this mini universe of my consciousness thinks a brain looks like) and it really is just a small fluctuation away from the large entropy state? Without that the second statement is invalid and only useful because we want it to be true.
Well done to George – opinionated, critical, and self-confident. What, however, has happened to the state of English teaching that a ten-year-old writes so abominably?
I mean, this:
was written by a twelve year old!
Admittedly, that twelve year old was Douglas Adams, but even he had to be taught how to spell.
(his first published work, a letter to Eagle magazine – and the only example of a twelve year old’s writing I knew would be on the web.)
lylebot, in principle (in the multiverse scenario where you have many copies, some possibly in the form of Boltzmann’s brains) you should define for any given person the class of observers that are identical copies of that person (identical means the person feels subjectively the same). We are then random samples within that class of observers.
If you do some experiment that has different outcomes distributed according to some probability distribution, then the entire class of identical observer splits up according to that distribution and you’ll find yourself having measured a particular outcome with the correct probability, only because you are randomly distributed among all your copies.
A theory that makes wrong prediction for probabilities can thus be ruled out. Any theory that predicts that most of your copies are Boltzmann brains can be ruled out because, apart from generating your consciousness, the Bolzmann’s brain will contain random information. You can prove that you are not a Bolzmann brain by checking that different sources of information (not related in any essential way to who you are) are consistent. E.g. if you as a Boltzmann brain check that a bill you payed has been written off correctly from your bank account, then you should find with almost 100% probability that it doesn’t add up.
So, the simple fact that everything is consistent rules out any theory that leads to almost all of your copies existing in the form of Bolzmann’s brains.
Yeah, straw-men are bad, unless accompanied by really cute writing style. So, in this spirit one can mention that currently nobody has any idea what the expression :it’s more likely: really means in this context, or if it is well-defined even in principle. Sufficiently smart people are working on this, so maybe this will become one day an old-fashioned style of argumentation, right now it is not.
Whether or not the above argument is correct is certainly a sensible topic for discussion. Comparing probabilities in multiverse scenarios is, to put it mildly, somewhat problematic.
Whether the argument above is correct or not, it is certainly not a good old fashioned style of argument, tried and true for centuries. So, It rubs some people the wrong way for more serious reasons than the ones quoted above. It would be useful for me to see this style of argument applied successfully in any context whatsoever, for example from all the possible planets how likely are we to live on earth? does that likelihood depend strongly on your model of planet formation? or is it much more dependent on what exactly you mean by “likely”?
What the B Brain argument shows is that *no* account of the earliest universe is satisfactory if it relies on fluctuations to produce fantastically low-entropy conditions such as those we currently observe [and which are responsible for our existence]. The whole project of trying to argue that the early universe was in some sort of “generic” state — from which the currently observed, highly non-generic universe emerged — is clearly doomed. The moral of the story is that the universe began, on the contrary, in an extremely specific state. People should be trying to identify that state and explain it.
Douglas Adams had Zephod Beeblebok on the Infinite Improbability Drive (IID). This takes you to the most improbable events in the universe. Ironically the laws of the universe are in a way similar to the IID. This is I think related to the initial entropy of the universe, which is (was) inordinately low and that the structure of fields and matter is such that the there is a maximal diversity of possible states or configurations. Maybe Leibnitz got it right with this being the best of all possible worlds.
Lawrence B. Crowell
PW said: I haven’t heard of any grown-up Ph.D. physicists who read the NYT article and didn’t understand that the goal of the active field of Boltzmann Brain studies is to explain why we don’t see them.
What about Lu….oh. OK. Grown-up. Right.
On the other hand, from what I hear, a very large number of physics Ph.D.s wish the NYT Science Times was not covering the spectacle of some of their colleagues arguing over issues such as whether consciousness is relevant for counting observers in the multiverse.
So you agree that the question of counting observers is interesting and important, you just don’t care whether they are conscious? Or are you in fact opposed to all speculative research in fields other than the one in which you are immediately interested? Or is it possible that you just want to use this question as another excuse to ride your hobby-horse?
Many would agree with the recent characterization of this by one well-known science journalist: high IQ pathology.
With a heroic effort I resist the temptation to make the obvious rejoinder.
What’s a Wolb Disiper?
Not Required (but really, is there a good reason for you to hide who you are?),
No, I don’t agree that the question of counting observers in the multiverse is important or interesting, based upon reading the papers of people working on the question and seeing what this work has led to.
As for legitimate speculative scientific research, I’m all in favor of it. On the other hand, I’m not in favor of pseudo-science, or its heavy promotion in the media, which is discrediting theoretical physics research in general.
Yes, this is my hobby-horse. I think the people involved in this need to pay attention to the fact that most scientists react to these anthropic arguments with visceral disgust, for very good reasons. Responding to this with postings making fun of 10-year olds and claiming ones colleagues are just too stupid to understand the significance of these arguments doesn’t help.
BFL – “Disiper” is obviously “disappear”. My best guess for “Wolb” is “world”. I get a lot of practice at this with four kids, two of whom are currently kindergarteners.
What does anyone think of modal realism, to ask again? That is so relevant to what it means to say “I exist” or anything for that matter. Can you defeat the arguments of people like Tipler (however eccentric) or Max Tegmark that all “mathematical structures” exist in the same way, and that there is no special status for “material worlds” as subsets of “model worlds” etc? Can you define “exist” in non-logic/math terms w/o begging the question? Note that if all such systems exist, so would all the equivalents of the “brain in a vat” just feeding false experiences to the brain! How could you tell the difference?
Ironically, a similar issue is brought against those (like me) who appreciate that “consciousness” is special and can be distinguished from “mere data processing” (altho I am a “property dualist” who thinks both are relative aspects of the same thing, rather than a literal dualist who thinks the mind can be pulled out of the body like spirit ectoplasm. (However, that doesn’t prevent that your mind couldn’t “run” on some other system in a multiverse, note that computer programs can run on other computers etc. I still don’t think it would be simple data but something more subtle.)
Organic Evolution is absolutely profound. We can understand where we (and our brains) came from- and understand our relationship (and that of all life) with the planet and the events which have ocurred since the origin of the Earth.
However, as satisfactory as the Evolution model is, we still know for good reasons rooted in Physical principles, that what has happened in the development of conscious complexity has to be undertstood from a more cosmological perspective than the “organic evolution” of our 4D frame of reference.
Invariant frames of reference and the general specs of a SR/GR/QM universe within a conventional (and congruent) marginally closed geometry demand just a little more profound explanation for the existence of information, complexity and consciousness in the universe than what happened as we observe and measure from our 4D frame of reference.
This is where things get a little “wierd” and we can look (and feel) like idiots.
We know there is something beyond what we see and the evolutionary processes we observe at our frame, but we don’t yet understand all the “whys and wherefores” as to how this link between intelligent consciousness and existence really works…we just know that this link is real- it exists and it needs an adequate explanation.
My hat is off to those who study the multi-verse concept but with all due respect, I think (for a number of what I believe are pretty solid scientific reasons) they are on a wild goose chase. In my own opinion, a single, multi-dimensional universe of vast but finite mass, existing within a limited spatial extent but in eternal time, and with certain inherent structural constraints could at least begin to explain the current universe we observe.
However, it is obvious that factors other than the chance of organic evolution alone have been and presently are at work in the universe. I’m reminded of the comment of Fred Hoyle when he found that the exact conditions necessary to produce carbon in correct amounts to result in life existed in the hearts of stars, and commented that “life monkeys’ around”.
NoJoy – thanks. You can tell I have no kids.
A Wolb Disiper sounded to me like some kind of undead creature from Transylvania – definitely not the sort of thing I would allow under my nose!
Errm. That would be, of course, if I had a nose. Which I don’t, being a disembodied brain.
Olfactory nerves, yes, but not connected to anything.
The kid was obviously wrong about some people having too much time.
Hi Sean:
Allow me a really stupid question, and I apologize in advance if a) the answer is obvious, but my aging frontal lobes are somewhat tired or b) you have already answered this question in previous posts (which I read, but might not have read too attentively as I find the whole topic quite bizarre). Let me leave aside for a moment the brain question, let me generalize that to the question of phase-space trajectories that actually lead to one of these alleged fluctuations. Consider a specific fluctuation (desk, brain, liver, other organs), and forget about QM for a moment. The universe is not a randomly evolving system, it has an evolution law. How do we know there are de facto initial conditions that, under application of the evolution law, do indeed result in such a fluctuation (up to some uncertainty). I mean, the notion of ‘fluctuation’ isn’t just an initial condition on a slice that could be put in one-to-one correspondence with any other slice, instead it seems to me to indicate a rather specific time evolution of the kind ‘wasn’t there’ – ‘is there’ – ‘won’t be there’ – how do we know this is an allowed solution? To come back to the brain how do we know one can ‘assemble’ a brain without necessarily going through all the evolutionary steps that brought us there?
Best,
B.
Re Moshe’s comment: “So, in this spirit one can mention that currently nobody has any idea what the expression :it’s more likely: really means in this context, or if it is well-defined even in principle.”
I think you have to distinguish between “not having a precise mathematical definition of something” and “doubting that something exists or is true”. Sean’s claim was that certain theories indicate that BBs are more likely than Ordinary Brains. It is true that a precise definition of “more likely” eludes us at present, but surely it is clear that it is *in some sense* true that low-entropy fluctuations are “more likely” than ultra-low-entropy fluctuations? Surely the onus is on *you* to come up with a scenario in which this reasonable expectation turns out, amazingly, to be false? To put it another way: do you really think that pointing out this problem contributes in any way to solving this mystery? Are we supposed to say, “Oh, right, we aren’t clear about the meaning of likelihood in this situation, so now I understand where the arrow of time came from!” One is reminded of the people who always like to object that “gravitational entropy” is not yet well-defined, as if making this statement removed all need to explain cosmological boundary conditions.
I’m sure that Sean can answer B much better than I can, but just to make a simple point: we are talking about theories in which a fluctuation prepared conditions suitable for an *entire universe* to evolve. Surely your observation applies to those theories even more forcefully? In other words, the answer to the question: “what makes you think you can assemble a brain by a fluctuation?” is “what makes Boltzmann think that he can assemble [the necessary initial conditions for] an *entire universe* by a fluctuation?”
An additional comment: you find the subject bizarre. I agree, it is bizarre. But it is *even more bizarre* to imagine that the initial conditions for an entire universe could have been the result of a fluctuation! It’s the old story: familiarity breeds contempt. You are so familiar with the incredibly unlikely [ = bizarre] initial conditions of our universe that you don’t stop and think: wow, do you guys seriously expect me to believe such a story? Yet when [extremely serious and respectable] people like Alex Vilenkin et al start talking about [far *less* bizarre] things like BBs, you feel incredulous. In short: when we talk about cosmological initial conditions we are willy-nilly dealing with fantastically improbable things. Emotions like “are these guys serious?” are not helpful at all, particularly when they lead to excessive hobby-horse-riding, an exercise likely to lead to further abrasive injuries to delicate body parts.