Cristi
The answer to your specific question is I do not know. But the point is that something happens, ie it is knowable if we had the wherewithall to discern it. Put the other way around, nothing happens which is contrary to how existence occurs, ie there is no pre-existent future, neither does observation cause a particular existence from a range of options, etc, etc.
Paul
Paul,
You say: "The answer to your specific question is I do not know."
This was the mystery I was talking about.
Cristi
There is no mystery, I am not a physicist, never claim to be one, and never make assertions about what is physically happening. I speak in the generic, and at a simple level, which is not philosophy. How what I am saying, generically, manifests physically, is an entirely different matter. But what I do not do is alter the rules whereby existence occurs and we detect it, in order to get a metaphysical theory to work.
Paul
Paul,
If you can't explain, then is a mystery. And it comes from experiment, not from a metaphysical theory.
Hi Eckhard,
thanks for the link, the paper is interesting for me too.
I read it and i think it is yet too technical for the average reader to understand. At least i didn't understand what is the "true" reason for the interference pattern to disappear in the case the screen is moved out of the experimental setup (Appendix A: Wheeler's thoughts).
Can anybody explain it to me in more intuitive words, with destructive and constructive interference instead of conditional probabilities and all that stuff. Means, that stuff is highly abstract but i want to know how one can put it in terms of physical processes (be it with or without time ordering).
Thanks in advance,
Stefan
Dear Christi,
your essay was an interesting read. I think your realization that ultimately, all we know of the world are relations is very deep, and is in a certain sense at the foundation of my own thinking, as well. However, I am less certain about the 'book containing every truth': this seems to me to run into trouble with the Kochen-Specker theorem (and related ones). In particular, if such a book existed, it would imply the existence of a global probability distribution such that its marginals give the outcomes for every possible set of observations; but this is known to be at variance with quantum mechanics. Put differently, while classically we can identify every object with a list of properties, of propositions true about this object, in quantum mechanics, no such list can exist. Any theory for which such a list exists necessarily obeys Bell's inequalities (and Kochen-Specker and Leggett-Garg inequalities, which are from this point of view just variations on a theme). (I think this connection was probably first worked out by Fine.)
Nevertheless, your big book seems to be very much a 'hot idea' in philosophy at the moment, after having been somewhat maligned after the 'noble failure' of Carnap's "Der Logische Aufbau der Welt"; three books have appeared in the past year dealing in various ways with the possibility of deriving all truths about the universe from some 'compact class' of basic truths: David Chalmers' "Constructing the World" (which is the only one I've read... well, I should say 'almost read'), Theodore Siders' "Writing the Book of the World", and John Heil's "The Universe as we Find It", so you're certainly at the bleeding edge in that respect! (Just in case you're interested.)
In any case, as a fellow PhD student in physics, I wanted to emphasize one point you made, though only somewhat implicitly, and only tangentially related to the main thrust of your essay: that of the necessity for courage in the scientific endeavour. Building on the Kuhnian model of scientific revolution, one might say that the ordinary, stick-to-the-mainstream method of science fails to produce the most important new ideas: it only clusters around local maxima, so to speak. For true innovation, one must sometimes leap beyond what seems reasonable, or even sensible within the current paradigm. Of course, many, if not most, such leaps will lead to nothing, which is why one needs courage to make them---a courage which John Wheeler certainly possessed, as you have shown in your essay.
Cristi
No, it means I have not got the knowledge to explain it, that does not make it a mystery. And no experimentation can differentiate one physically existent state, because of the degree of complexity and duration involved, along with the fact that we only receive a light based representation of it anyway, which makes it more impossible than it already was(!).
So even if I had more knowledge, I would not be inclined to junk what must be how physical existence occurs, for an alternative explanation which cannot possibly support existence, in order to accommodate what appears to be the result of experimentation, when experimentation cannot differentiate existence at the existential level.
Paul
Dear Cristi,
"it comes from experiment, not from a metaphysical theory." Wasn't Wheeler's original experiment just a Gedankenexperiment intending to support his theory?
I understand your intention to not get suspected as someone who questions Einstein's theories while you simultaneously maintain your desire to explain what are so far mysteries to you. Yes, George Ellis and many others were successful trying the same in the contests. However, in reality being a bit pregnant is impossible. I have to admit that I was mislead e.g. by Feist's experiment. The truth is sometimes unexpectedly simple.
Paul,
I am not interested in quarreling with you. We agree in many decisive points. However, I still tell you that in any (stationary) electric measurement the non-ideal impedance of the instrument disturbs the voltage or current to be measured. The instrument correctly measures a quantity that in reality belongs to the disturbed case. Knowing the error, we may exactly calculate the undisturbed reality. The latter possibility also holds for two-way non-Poincaré synchronization.
Eckard
Dear Jochen,
It's a pleasure to read such deep and well thought comments. Thank you for the attention given to my essay. I look forward to reading yours asap.
You said "I am less certain about the 'book containing every truth': this seems to me to run into trouble with the Kochen-Specker theorem (and related ones)." Any theorem has a domain of applicability. The Kochen-Specker and co. theorems are a great toolbox, with which I fully agree, and which rule out a certain class of attempts to describe reality. It would rule out the book containing every truth, if you would want it for instance to contain information about what the spin is along each direction, which will give definite results no matter how we will choose three orthogonal directions along which we measure the squared components of the spin. But I make no such claim. If one of the truths is what the squared components are, this should be accompanied by the three directions along which we measure. "Put differently, while classically we can identify every object with a list of properties, of propositions true about this object, in quantum mechanics, no such list can exist." I agree, but it makes no sense to have such a list in the book. I don't claim that the book will contain both position and momentum of a particle. This makes sense only classically. If you want it to contain both, you will run into the trouble you mention, but there is no need to do this. Why asking the state vector to be simultaneously eigenstate of incompatible observables? It is like asking the insect to be both a fly and a dragonfly, at the same time. To refer to the delayed choice experiment of Wheeler, if you want the book to contain information whether which-way or both-ways, it also has to contain information about whether the second beam splitter will be in place or not. The book should contain proposition about elements of reality, only together with the context. I tried to capture and explain this using the concepts of "delayed initial conditions" and "global consistency principle". Conditions at various points in spacetime should be mutually consistent, even if they are one in the future of the other, even if they are separated and can't exchange information without violating the speed of light.
Thank you for the references you gave, I am interested in principle. With "the book", I just wanted to make the point of how mathematical our universe can be. I am not sure I want to develop more this idea, but no matter if I will or not, I am sure the references you gave me will be very useful.
Best regards,
Cristi
Eckard
I agree with you, as I said in my post. But this practical problem is not what QM alludes to. It does not start with the premise that physical existence occurs independently, in a sequence of definitive discrete physically existent states. And then accept that trying to identify those experimentally is fraught with practical issues. Indeed is it impossible for us to differentiate such states experimentally. Rather QM asserts that there is some form of indefiniteness inherent in phyical existence. Which is quite obviously wrong, because existence cannot occur that way, apart from the fact that observation/measurement can have no effect on the physical circumstance because it has already occurred.
Paul
Jochen
"while classically we can identify every object with a list of properties"
But we cannot. There is no object, physically. That is a conception at a much higher level than how reality occurs, based on certain superficial physical attributes. Which is why the classical/intuitive view has been denigrated, because it has not been followed through to its proper logical conclusion,But left at the ordinary everyday way of seeing things. And usurped by an incorrect view. Physical existence only occurs in one form.
Paul
Christi, yes, I think I missed the importance of your 'global consistency principle'. Indeed, if you intend for the big book to contain truths that include their proper (measurement) context, then you avoid the difficulties with Kochen-Specker etc.
I think I see two ways how this might work: one is a kind of 'superdeterminism', where what measurements are performed is fixed for any given instance; the other amounts to the book containing truths that are conditional on the performed measurements. It seems to me that you advocate the former strategy: the world is, in a sense, given by an action principle; it is like the famous catenary problem, wholly determined by initial and final conditions. The latter strategy is essentially what I've argued for: the book only contains relative facts, of the form 'if such-and-such a measurement is performed, the outcome is this-and-that', which then sort of co-exist peacefully. So maybe our perspectives are not that far from one another!
Also, somewhat amusingly, both solutions have a distinctly Leibnizian character: yours pertaining to his notion of the 'best of all possible worlds', while mine relates to his overall relational philosophy.
Paul, in a classical world, you can certainly always draw up a list of properties, and then clarify by that what you mean when you talk about 'an object'. What happens at the foundational level doesn't really have a bearing on this.
Hi Cristi,
In your essay you have touched the roots of science. Excellent and interesting. I have read it twice and I would like to comment barely every sentence but I don't want to torment you so much. So let me please to leave only a few comments of my choice.
1. You find compelling the idea that our universe is mathematical in the sense of relations. This is widely accepted that only waves or rather wavepackets give an information about the universe, the information which is accessible to observers (e.g. gamma rays, sound waves etc.). Then let us assume that Axiom Zero sounds like that: primordial conformally flat spacetime is the 'fabric' of everything. Everything could be derived from the spacetime and everything could vanish in it. Assuming then that a wave is only a spacetime dynamic deformation (also Clifford's and Wheeler's concepts) then the mother of all possible worlds could be our conformally flat spacetime (details in references to my essay concerning relations between it, bit and reality). Consequently the observer is also a wavepacket (deformed spacetime) so its participatory role is his own wavepacket's interference with another wavepackets. If we assumed that any spacetime deformation is unlimited (to some extent it deforms the entire spacetime e.g. in Gaussian distribution mode, due to its elastic and homeomorphism properties) than we could say that this is our participation without a need for many worlds interpretation!
The geometry is a part of mathematics and is completely about relations. But does the spacetime need a mathematics to exist? Or only we (observers) need a communication tool? This tool helps us to replicate our genes successfully (Darwin's survival of the fittest). I have touched the spacetime / geometry issue truly because my memes (information) try to replicate.
I know that this is only your essay's intro and not the point where you have noticed that Wheeler and his students wanted to obtain the mass and the electromagnetic field as effects of the topology of spacetime. They failed. But I have to comment shortly. Their problem was they were chasing geon solutions to the vacuum Einstein field equation (partially made by Brill and Hartle in 60's). A major issue regarding geon was whether it was stable and it was not a quantum-mechanical entity. This wrong approach has buried the very idea that the mass and fields can be effects of the topology of spacetime. In order to combine statistical nature of QM with geometrodynamics (any kind) we need the general law of survival of the stable. Quanta are just that stable wavepackets so we are able to perceive them.
2. Regarding your version of the delayed choice experiment the most interesting from my point of view is what is going on at the mirror A. I have proposed a simple spin experiment to find out and at the same time to make my concept falsifiable (details in references to my essay).
3. '...it seems very plausible that there may be a (possibly infinite) collection of propositions which contains all the truths about the universe. In this case, we have a theory (of everything). To the theory we can associate a model, in the sense of model theory.'
Such a model would contain propositions that are computable and deterministic. But if the universe is SOC system? The universe evolution (naturally evolving self-organized critical system) is non-computable and non-deterministic.
Jochen
"Paul, in a classical world, you can certainly always draw up a list of properties, and then clarify by that what you mean when you talk about 'an object'. What happens at the foundational level doesn't really have a bearing on this"
Well, apart from the fact that I said the opposite is true, ie there is no 'object', why is it that the 'classical' view does not deal, or could not deal if properly understood, with the foundational level? Indeed, why are there two levels, somewhat wierd isn't it that physics has two explanations for the same thing, ie physical exstence?
Paul
Dear Jacek,
Thank you for the careful reading and the comments. I find interesting the way you see the first axiom of the universe. Later, you ask "The geometry is a part of mathematics and is completely about relations. But does the spacetime need a mathematics to exist?" I am not sure how they can be separated, so that spacetime can exist without math. I don't understand what you mean. Say math was never discovered, and somehow all humans would have evolved, as people who know to survive, develop various crafts, and maybe arts, but no math at all. I find very possible, and if there is such a civilization in the universe, I think one should not consider them inferior, just because of that. But, I don't think they can do without math, in the sense that math is implicit anywhere. A spacetime without math, I can't picture. Our spacetime doesn't seem to be without math. Perhaps the subsequent comment you make, about the failure of geometrodynamics, explains what you meant. Maybe the final word is not yet said. Some things they tried worked, but not all, who knows what will be. About the book of true propositions, it will contain every true, including the ones you refer to as not computable or not deterministic. I don't claim that the book is a finite set of axioms, and the consequences that can be proven by finite length proofs. It contains everything. I hope figure 8 in my essay clarifies this. Good observation, it gave me the opportunity to explain better!
Best regards,
Cristi
Dear Cristi,
You refer to "...does the spacetime need a mathematics to exist?" I am not sure how they can be separated, so that spacetime can exist without math...
I will try to explain: the spacetime can be defined only as a mathematical entity created by observers (Platonic) but it is not necessary. It can be defined as a purely physical entity (real) that does not need observers. As you see the approach to spacetime can be dual: one mathematical and one physical (Einstein also attributed an elasticity property to the spacetime regarding it as physically existing entity but not the ether). I don't know if my view is clear. It is a lot of language intricacies and philosophy involved in the issue. It is very hard and maybe impossible to stay independent from our language and culture notions.
Jacek,
If I may offer up a point about time, ask yourself the question of whether it makes more sense to say the earth exists along a fourth dimension, from yesterday to tomorrow, or that tomorrow becomes yesterday because the earth rotates?
As I see it, the problem is that we experience time as a sequence of events, much as we still see the sun moving across the sky, from east to west, yet like the underlaying reality of the earth spinning west to east, it is the events moving through the physical actuality of what is present, as it is constantly changing, not the present moving along some extra-dimensional vector.
Because physics treats time as only a measure of duration, it re-enforces this sequential perception, rather than revealing its cause. Duration is not an external vector to the point of the present, but is the state of the present between events.
As effect of action, time would be similar to temperature, much as frequency and amplitude are features of waves.
So spacetime as causal, is no more real than giant cosmic gearwheels spinning in the heavens, as explanation for the mathematical effectiveness of epicycles.
John
The present becomes the next present due to alteration, and ceases (because it has altered)in doing so. There is only ever a present. There is no existent tomorrow or yesterday, or more precisely preceding or succeeding physically existent state. The 'fourth dimension' is not a spatial dimension, it an aspect of sequence, ie the rate at which the turnover of presents in the sequence occurs. We calibrate it (aka timing) by comparing rates of change and identifying difference. Physcal existence is a purely spatial phenomenon, though it has more than 3 spatial dimensions.
Paul
Paul,
We agree on that. The disagreement is on how it comes about. You seem to see it as fundamentally discrete events and I see it as how we discretely perceive a dynamically continuous process.
This "book" can be thought of in a number of ways. The book might be a set of tables, where these tables contain the states under some set of projector operators. This particular book though is incomplete, for there exist other books of the same form, but the books are not consistent with each other because the probabilities violate Bell inequalities.
We may look at these books as propositions that are connected by a disjoint "OR" operation. In that setting the books become elements in systems of relationships. Within that sense these relationships describe a set of geodesics that have a measure over Hilbert space.
Cheers LC