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2011-03-04
Are the physically possible worlds the same as the logically possible worlds?
I ask this question from a position of profound ignorance of physics.

I would have answered the question in the title with a reflexive "of course not" until just a few minutes ago when something occured to me.

As far as I know, it's entirely possible that it was [i]physically possible[/i] for all the constants of nature could have turned out to be different. This, in turn, would have made for worlds in which the laws of physics would have appeared quite different to creatures inhabiting those worlds than ours appear to us, up until those creatures had succeeded in completing a full and correct theory of everything.

So what constraints are there on these basic constants? Are there any but mathematical constraints? If not, isn't this tantamount to saying there are none but logical constraints? If that's so, then, doesn't this imply that the physical possibilities are exactly the same as the logical possibilities?

Another way to put it: If a multiverse theory turns out to be correct in physics--if for each possible waveform of the universe there is in fact a universe corresponding to that waveform--then are there any constraints on waveforms other than mathematical constraints, and if not, then doesn't wouldn't that imply that the physical and logical possibilities are identical?

And then even if multiverse theories turn out to be wrong, wouldn't the space of [i]possibilities[/i] be the same as the ones defined by the set of multiverses, meaning the point still holds?

-Kris Rhodes

2011-03-05
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes

My question - which I think is related - springs not only from a position of profound ignorance of physics but also of talk about 'possible worlds'.

If indeed there is a vast (infinite?) number of other universes - a hypothesis I am quite happy to entertain - how can we talk about 'laws of nature' at all?  The laws of nature would presumably be those of 'nature' in our universe, would they not?

Further, if something like the multiverse theory is correct, are we not obliged to adopt a position of complete agnosticism about 'possible worlds'? Do we not have to accept not simply that conditions in other universes might be different in imaginable ways, but that they may be different in entirely unimaginable ways, so that all our 'logics', all our knowledge, all our ways of understanding, speculating and imagining, might simply be irrelevant?

Can we then talk about 'possible worlds' at all?  We would surely be in the position of not having the slightest idea what might or might not be possible?

An interesting thought, it seems to me. It not only gives a new meaning to the idea of agnosticism, it makes one think how utterly contingent and arbitrary human life, and everything we associate with it, may be...

DA


2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan

This follows on from my previous post.

I haven’t given much thought to this topic before but, now that I do, it seems quite intriguing.

If we accept the possibility of a multiverse – and I don’t rule it out – and if we concede that there may be an infinite number – or even just a vast number – of other universes unlike ours, then the familiar philosophical idea of a ‘possible world’ becomes very suspect, doesn’t it?

That is, we would surely have to admit the possibility of what might strike us as totally impossible, even totally unimaginable and inconceivable, worlds – worlds quite outside any constraints, scientific, logical or anything else, that we might think necessary? 

If we don’t accept this consequence, we would seem to be saying: ‘Yes, there may be an infinite number of other universes, but they can only be of a kind that we humans can accept as possible.’  What would authorise that proviso?  To me, for example, 2+2=5 is impossible; but why should there not be a universe in which it is true? Or one in which 2+2 = 234,321.33 recurring. Or, indeed, one in which addition is not even possible.  

If this reasoning is correct (and it may not be, so I would welcome comments), then the familiar gambit ‘There’s a possible world in which…’ becomes otiose, does it not? That is, there would be no foundation for such a statement since we have no idea what the limitations (if any) on ‘possible worlds’ might be.

How distant seem the days of Leibniz now!

(I should not permit myself this further thought, but is this a case of analytic philosophy being hoist on its own petard - of the mathematico-scientific orientation coming back to bite it?)

DA.


2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
Kris,

The idea of multiverse originates from the many worlds interpretation of quantum theory. This interpretation was put forward by Hugh Everett to explain the Einstein Podolsky and Rosen paradox from quantum physics.

I do not think it is necessary to introduce the notion of many universes because there is a plausible and classical physics explanation possible for the quantum paradox. I claim, with sufficient aargument, that Einstein was right, there are local hidden causalities and they explain the Heisenberg Unscharfigkeit i.e. the EPR paradox. In physics there were in the 50-ies experiments
that demonstrated that the weak nuclear force was not invariant to parity. Because Lorentz transformations are considered universal this entailed the possibility of mirror matter i.e. matter that exists in the same space time (universe) as ours, has only gravity interaction with (ordinary) matter and can therefore be employed in the explanation of Dark Matter observations.

The problem of a classical probabilistic explanation for the EPR plus the problem of matter to gravity transformations were solved. I can send you my papers and preprints to demonstrate that. 

Now most of the time people tend not to belive that the EPR (Bell theorem) is tresolved with mirror sector cosmology. They cling on to the older explanations of non-locality and many universes. However, my explanation is the most physical in terms of experimental proof (Ambler, Hayward Hoppes and Wu Phys Rev 1956) and in terms of mathematics (Geurdes Adv Std Theor Phys 2010). 
   
Han Geurdes

2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes

Dear Kris,

In addition to the notion of the physical necessity there is of course the philosophical possibility of a multiverse. This is, I think, purely an excercise in Logic and is unrelated to physical parameters. One can imagine a universe with a slightly different Planck constant etc etc etc. The physics in such a universe will not be altogether very different from ours. Of course there is the Logical possibility that in a multiverse there are universae that have a completely different physics.

Of course, a study of different universae with different physical constants will provide insight into the role of the physical constants.

Now in mirror sector cosmology, there is the concern of numerically simulating the consequences of mirror matter to the development of the visible / observable universe. E.g. the creation of galaxies. In this study, the necessity arises that mirror matter is colder than matter because otherwise there would be deviations from the established observations.  This is in essence a Logical (numerical logic) study of a bi-sector universe. This is not a multiverse but can, perhaps, serve as a paradigm to multiverses.  

Moreover, there are experiments like DAMA/LiBrA and CoGeNt (see: R. Foot, A CoGeNT confirmation of the DAMA signal (2010), arXiv:hep-ph/1004.1424v1).

With these experiments possible gravitation anomalies are detected and ascribed to mirror matter.

Han   



2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
Following Descartes mathematics (logic) determines which worlds are possible, (experimental) physics shows which of these possible worlds are real. In so far that mathematical physics equals mathematics all logical possible worlds are also physical possible and vice versa, under condition that no universe exists where the laws of logics are not valid.  About such universes nothing can ever be said as our brains are finite 'thinking engines' 

2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes

It is possible that a number of universes exist, say one with Plank's constant as is ( a "p-unvierse") and one with Plank's constant at twice the value in our universe (a "q-universe").
 
In the language of possible worlds the possibility is expressed by stating that there is a possible world with both a p-universe and a q-universe.  It's possible that no mutli-verse exists, so one possible world just contains a p-universe.  It is also possible that Plank's constant could have been q with no multiverses, so one possible world contains a q-universe and no other.

Multi-verses are parts of possible worlds, not possible worlds, so the logically possible worlds are not identical to the physically possible worlds.

Tony


2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
A deep and interesting question. Somewhat contrary to you, I beforehand tended to reflexively say "yes" (maybe due to me being a physicist). But upon rethinking I now think that there's a straightforward counterargument.
The very notion of a law entails a restriction, namely that from a (maybe infinite) set of possibilities that are there without that law, to a smaller (but maybe still infinite) set of possibilities in agreement with the law. A law that doesn't impose any restriction on anything, simply isn't a law. I think this holds in generality. But let's turn to physical laws. A physical law is, in the broadest sense, a restriction on the set of possible states of a physical object to be in. The Maxwell equations, for example, rule out for the electric field to propagate totally independent from the magnetic field. Both fields dynamically depend on each other in a lawful way. If the Maxwell equations would not hold, then there would be a lot more freedom for electric and magnetic fields to evolve. But let's proceed: the Maxwell equations still leave open the possibilitiy of there being such thing as the ether as their medium of propagation. However, nobody found any evidence for the existence of an ether, and Einstein finally put an end to it by introducing his special theory of relativity which is not consistent with the existence of an ether any more. That is, his theory is more restrictive (and also contradictory to old-school Newtonian mechanics, for that matter). Since then, there has been plenty of evidence in favor of that new theory, so the scientific community had to abandon the ether as a possibly existing thing in this world. But the existence of the ether is still logically possible (that is, by denial of the theory of relativity). Thus, as we have empirically found that Einstein's theory is correct (so far), we have to exclude the physical possibility of the ether in this world. There are, however, infinitely many logically possible worlds where Einstein's theory does not hold, and in some of these worlds there is an ether. In our world, there is no ether, but the set of possible worlds consistent with there being no ether is, of course, still infinite. In fact, the set of physically possible worlds consistent with all our most modern theories is still infinite, to the grief of physicists hoping for the "theory of everything".
Concluding, the set of logically possible worlds is (by far) not equal to the set of physically possible worlds, if by "physically possible worlds" we mean those worlds that are consistent with physical laws, including all their variations (like different values for the elementary constants and such). Progress in physics is finding stronger restrictions on the set of logically possible worlds. If you took away all physical laws, then the set of "physically" possible worlds would become equal to the set of logically possible worlds, but then this wouldn't mean a lot any more.


2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
Dear Derek,

Thank you for your comments.

What do you mean by 'this follows from my previous post' ? What follows ?

If a multiverse is admitted and people can make a theoretical study of what happens with physics when constants are changed it will only show that some combinations of physical constants will not lead to a Universe like ours. E.g. formation of galaxies.

There is this anthropic principle based on an older study of Paul Dirac on the physical constants. Note in addition, changes in physical constants are not changes in physical law by necessity. If I have a different Planck constant there is still the possibility to have for the energy of the photon with frequency, f,

E=hf.

This is a different Universe form ours but also from the one where E is not equal to hf. One may wonder if this is possible at all.

Indeed, agnosticism at every solid angle of the (radio)telescope observation. But we only observe one universe. The bi-sector mirror matter hypothesis is still in a single universe. In the mirror sector there still is e.g.  E=hf and, c=300000000 m/s etc are shared between sector and mirror sector.

Analytic philosophy was there in the first place to study the language of metaphysics. E.g. the language of Hegel on the Absolute and of Bradly a Hegelian in the UK. Russell and Moore started the analytical 'school' in order to study the language of metaphysics. Wittgenstein went as far as to reject all violations of the language 'border' any credibility.

However, in case of cosmology and fundamental physics we need to step into the dark to see if such a language border is crossed. Analytical philosophy is therefore not attacked by scientific development. It is an instrument of exploration.

Yours
Han

2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes

Hello Han

I only meant 'follows' in the sense of addition. I had been thinking more about the issue and wanted to add to what I had said.
 
I am neither a scientist nor a mathematician so I can’t comment on those aspects of your post or of others who have made similar comments here.

I would just make a couple of points:

(1)    It was my amateur understanding that some multiverse theories admit the possibility that other universes may be utterly different from ours – that none of what we understand as ‘laws’ might apply in them. Is this understanding incorrect?  Has this possibility now been definitively ruled out and is this the unanimously agreed position?

(2)    How odd it now seems when philosophy – at least of the analytic kind – seems so heavily dependent on advanced physical and mathematical reasoning of the kind you and others have put forward. It’s as if analytic philosophy now finds itself in the embarrassing position of perpetually waiting for the latest news from physicists so it can know what it’s allowed to think!* Do you think this explains why Stephen Hawking has been arguing (as I read recently) that ‘philosophy as practised nowadays is a waste of time and philosophers a waste of space’? Does he have a point, do you think?

DA

* The same seems to be true in the analytic philosophy of consciousness where neuroscientists play the same role.


2011-03-09
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
Hello Derek,

Ah thanks I see what you mean by 'follows'. 

Concerning (1)... I cannot really say anything about that at all. There is a need of theoretical study similar to e.g. Dirac's to see if laws changes when constants change. I know of work of A. Maslov on algebraic ring theory. Essentially the form of mathematical structure remains the same (e.g. an integral) but the numerical definition changes -e.g. a + is translated to a max operator-. His claim is that he can, by doing so, go from the quantum to the classical domain. This is interesting math.

Concerning (2). I absolutely do not agree with Stephen Hawking's claim that philosophy is a waiste of time and space (or spin). I see analytical philosophy as an instrument for cosmology. And we are going to need that very badly. In the sciences there is much (too much) 'believe and conviction' floating around in editorial offices of top journals. This alone is sufficient ground for analytical philosophy. Assumptions and basic admissions of anomalies in mathematics need to be studied carefully. Not only by the (biased) experts but by the unbiased philosopher who 'wonders'. 

On a journey like the Vikings did, some stand at the helm, others are on the look out, others repair the vessel on which they float, still others design the instruments to navigate etc etc. A helmsman is not better than a designer of instruments or a person that repairs the boat 'while floating'. So,..., well.

Han


2011-03-10
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes

Hello Han

Thanks for your reply.

If I understand you correctly, it is still regarded as a possibility that under certain multiverse theories, other universes, if they exist, may be utterly different from ours, and that none of what we understand as ‘laws’ (logical, scientific, or otherwise) might apply in them?

I find the point interesting. As I say, it would throw considerable doubt on the familiar philosophical gambit 'There is a possible in which...’, since any world, conceivable or inconceivable, might be possible, and the locution would therefore be superfluous – indeed virtually nonsensical.

Your simile of the Viking ship is a colourful one but it does seem to imply that analytic philosophy is along for the ride on someone else’s journey.  On this view, analytic philosophy does not seem to have any independent raison d’être. It is forever destined to be handmaiden, interpreter, under-labourer, etc in enterprises in which it has no hand in setting the agenda.

DA


2011-03-10
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan

Hi Derek,

The question of many universes was raised -as far as I know- in physics for the explanation of the EPR paradox. It was Hugh Everett that came with the possibility (underpinned with mathematics). Somewhere in my files I have a nice review of Everett's adventures with Wheeler and Bohr.

I simply do not know if there are other universae and the relation to physical law. In addition it is not necessary anymore to entertain this idea for the solution of the EPR paradox.

On the contrary I would propose a consistent solution of the EPR riddle by pointing at the weak interaction parity non-conservation (demonstrated in beta decay) and the fact that Lorentz invariance was introduced in the equations of quantum theory exactly to match special relativity to quantum theory. Schroedinger tried that first when he was seeking for a mathematical model but he failed.

The bi-sector hypothesis of a single universe is sufficient at this moment to explain the EPR paradox in 'classical' causal terms. The global Lorentz invariance (parity is a Lorentz transformation) is theoretical evidence. Dark matter observations could provide the experimental evidence (plus the DAMA/LiBrA observations and gravity anomalies).
 
Now that is already hard enough to understand. Not only on the level of physics but also on the more conceptual level. Aparently the paradox in quantum theory can be explained with postulating two instead of one 'sectors' in a single universe. What do we know about our single observable universe and is it already enough to say something interesting about other universae? Think about matter and anti-matter in a single universe. The bi-sector cosmology points at matter plus anti-matter in one sector and mirror matter plus mirror anti-matter in the other sector.

I think we do not know enough about the observable universe. The bi-sector explanation e.g. is already hard to grasp and experiments are very difficult to interpret. You are in Australia so you clould ask Robert Foot. He works at the astrophysics department of ANU I believe.

About the colourful Viking story. No, analytical philosophy is just one of the instruments man can use to get grasp on (his position in) the universe. Sometimes A.Phil. will be the most important thing to do, other times it could be a nuisance. Yes indeed Cosmology and Philosophy and Astrophyiscs and Astroseismology and what have you ... all contribute to the agenda of the journey. Do you think that those colourful Vikings would be arguing about whether it makes sense to repair the boat? No they would repair it and then do something else.

Now nobody can have knowledge of the he unknown. Otherwise we would not be calling that so. Agreed? I know I am on a philosophers site so this will be laughed at but try to argue against it.

I can think about what could lie ahead to plot a voyage but that does not mean to say that the Ocean is friendly enough to behave the way I think it should. Knowledge is an instrument to get somewhere. It can be a beautiful thing of art this knowledge of ours but still it is an instrument to survive.  

We learn about our own Universe by imagining different ones. In this way we could  learn why the constants are as they are and whether there are laws that remain unchanged -because otherwise no physical reality- or whether some can be changed. In that way we have learned laws of the basic fabric of physical universe. 

The Ocean so to speak will be a mystery after each next 'wave'. Do not cry about the fact that you lost sight of the shore. It is already washed away. The philosophy of washed away certainty as a replacement of the philosophy of analysis (because there is the need of something to analyse in analytic activity).

Han   


 

 

 


2011-03-10
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes

Hi Han

Thanks for your comments. You write 'Now nobody can have knowledge of the unknown. Otherwise we would not be calling that so. Agreed? I know I am on a philosophers site so this will be laughed at but try to argue against it.'

I agree with you. I was probably not clear in my last message but I was not really lamenting the loss of certainty. I accept that situation. I was just suggesting that analytic philosophy seems very often to be tagging along behind science, without any clear goals of its own.

I am also interested in the multiverse idea. I gather from what you say that the jury is still out, but it's an interesting idea nonetheless. We are all so accustomed to thinking in terms of natural laws, logical possibilities etc, it's quite mind-boggling to ponder the possibility that there may be other universes in which such things have no application at all.

Analytic philosophy has a tendency to do what it calls 'thought experiments' where it sometimes imagines 'possible worlds' in which conditions differ from our own. But once one introduces the multiverse possibility into the philosophical equation, the very thought of 'possible worlds' begins to look very shaky. I mean, once one accepts that 'possible worlds' might include many which we can't even imagine - even conceive of - then we seem to be employing a notion which we no longer even understand.

DA



 

2011-03-10
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
Derek,

Yes I think I agree. Pondering on possible worlds that in effect cannot be possible at all because of violation of large scale physical constraints like galaxy formation, is pointless. I wonder why one would do that. Is it Wittgensteinian 'crossing the language border' methodology?

Moreover, bi-sector cosmology is explicitly single universe cosmology. Bear that in mind please.

You 'phillies' are strange folk if you forgive me my pun. You labor at the front of what can be thought and experiment with concepts. That is perfectly in order. Then some scientific fact comes along and restricts somewhat the mental liberty. Then all of the sudden one is affraid that analytic philosophy is the slave of cosmology. 'Aux contraire' I would like to say. The 'grammar' of the thinkable is somewhat restricted but that leaves the philosopher quite some lattitude to investigate possible universae.
 
I do not believe in the necessity of multiple universae. But I am still wrestling with my quantum cosmology and Robertson, Friedman and Walker leapfrog algorithm for Baby Universes. I am lagging behind ways.

You can philosophize about possible worlds as long as you e.g. do not take a bi-sector universe with a mirror sector that is hotter and more dense than our common matter. Because in that case we would not have seen galaxies.  

For the rest, but do read some  cosmology please (e.g. P. Ciarcelluti, Int. J. Mod. Phys. D. (14)  187-231 (2005) ), ... it is free ... enjoy. Perhaps better ask Paolo to guide you through the mirror sector cosmology himself. He has gmail: paolo.ciarcelluti@gmail.com,  give him my regards and my wish he returns to active cosmological research.

Han

2011-03-13
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
The word "possible" needs its counterpart "impossible" to obtain any meaning. Possibility is always and only relative to some set of restrictions. There is no such thing as possibility per se. A "logically possible" world is a world that doesn't contradict the laws of logic. What about a world where the laws of logic won't count? Such a world is certainly not logically possible, but it might be a possible world relative to something else than classical logic.
A "mathematically possible" world does not contradict mathematical laws, but here one has to make clear what set of mathematical axioms those laws are based on. There are mathematically possible worlds with the lemma of Zorn being true, and others where it is false. There is a mathematically possible world without addition, with just the axiomatic foundations of addition denied and all the more basic axioms left intact. But that doesn't mean that in that world addition is impossible. It's just not there. Now, a "physically possible" world is a world which is possible relative to some set of physical laws. It might be the set of physical laws that is valid in our world, but it also might be some other set of laws. Since physical laws are something else than logical laws, the physically possible worlds are not equal to the logically possible worlds.

This all has nothing to do with the Everettian multiverse. In fact, the Everettian multiverse is a very restrictive set of physically possible worlds. For example, it does not contain the worlds where Bohmian mechanics is true, although the Everettian as well as the Bohmian worlds describe the same quantum phenomena that we observe in our world (at least in the non-relativistic domain). So maybe they are not even distinguishable by any observer. (This is a matter of strong controversy, though.)

Moreover, the physically possible worlds and the Everettian multiverse have nothing to do with the parallel universes conceptualized in kosmology, which are something else entirely.


2011-03-13
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes

Derek’s gadflying seems on target here. Surely, the possible worlds of philosophy of language have little to do with either a real (possibly) multiverse (which, pace Han, is unrelated to the quasi-Everettian 'many worlds’ solution to actualisation in one parameter set, as far as I know) or logical possibility. When possible worlds were introduced to deal with intension many philosophers indicated they were talking more of possible situations relevant to routine use of in language (‘The bus never came.’, ‘I hope you catch some fish.’). Possible world arguments about conceivability seem to me hopeless, not least because a standard tenet of modern physics is that what is really going on in the world will by definition be unenvisageable. Thus, I tend to see the problem for analytic philosophy as less a slavish following of science and more a picking up of scientific fag ends and trying to smoke them from the wrong end (Ramsey-Carnap disease).

In relation to Kris’s original question, I would say that:

1. Physical possibility (whether epistemic or ontological) is what falls within the laws of physics as they apply here. Anything beyond that does not deserve the word physical, which has a pretty vague and misconstruable meaning at the best of times. Broader conceptions of possibility need to be defined for each specific discourse.

2. Logical possibility distinguishes things like: a world in which all gruebs with four dangles have yerks, and no other true statement can be made about this world; and, a world in which all gruebs with four dangles have no dangles and no other statements about this world are true. It seems to run into something like Russell’s paradox when we get to whether worlds in which our logics do not apply (very likely if physical laws are substantially different) are logically possible because there seems to be no logical contradiction here yet there seems to be a semantic contradiction.


2011-03-14
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
Please note:

>>>As far as I know, it's entirely possible that it was [i]physically possible[/i] for all ... (expand) the constants of nature could have turned out to be different.

The anthropic principle illuminates the fact that the constants of nature are in a somewhat narrow bandwidth in order for us as observers to exist. E.g. galaxy formation and the possibility to form planets around stars (and the contraction to form stars from H gasclouds) and the possibility to have the proper atmosphere and the necessity to have all the chemical processes such that enzymatic reaction speed-up may occur and the necessity to have a 'memory molecule' like DNA.

I think I may claim that in order for us to ask this rather redundant question about many universea there is a narrow  bandwidth of physical constants. But,...., I do not know the width of the band. Moreover, logical possible means nothing. I can form meaningful sentences with all kinds of not observed entities that I may claim to exist. I can even ask logical questions like what is the number of angels dancing on a pin. But can I answer the question?

You seem to be in the business of asking questions. That is perfectly ok. But if you are getting confused between finding good questions and providing good answers then one sees confusion arising about the role of logic and the role of language analysis.


There are my five pennies.


2011-03-14
Are the physically possible worlds the same as the logically possible worlds?
I find relation between physical and logical possibilities get interesting when an uncertainty ingredient is being introduced. Talking about many worlds, it was Kant who wondered whether God perhaps created the Universe in the shape of one single human hand. If it was so, then physicaly it is absolutely impossibile for the Universe to be both left and right and logicaly it is absolutely imposible to decide whether it is the left or the right one. If we take physical possibility to be concerned with actual existence (the Universe is actualy restricted to be one of the two, i.e. either the left or the right) and logical possibility to be concerned with absolute existence (there is an absolute uncertainty which of the two /logicaly posible/ Universes is actual) we see that absolute (logical) and actual (physical) existence "entangle" through the actuality of absolute uncertainty.

Same goes for rather naive conception that universal constants of nature might differ in magnitude in different worlds. Universal constants are finite and yet they are absolute. There are absolute limitations but there are no limits to absolutness. Say, the velocity of electromagnetic propagation is absolute and it can not be affected physicaly, it is beyond evrey causal history. The speed of this propagation is 300,000 km/sec meaning that it is finite and is measured as congruent with durations of other events in nature. However, please notice that different magnitude of universal constant of elctromagnetic propagation in some different world would entail measuring units in that world congruent with measuring units in our world. Since the measuring units in any world can be normalised to universal constatns of nature in that world, the congruency of measuring units of two different worlds renders itself impossible if the universal constants are to differ. Ergo, different worlds would be incommensurable and different magnitudes of universal constants just make no sense.

2011-03-23
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
Hi Kris,

Suppose we individuate ingredients by everything that is true about them, including their laws.  Then take an arbitrary ingredient x.  If x-particles are defined as obeying the laws in set L, it would then be true in every possible world (even worlds that don't have x-particles) that x-particles obey the laws in set L.  If so, all physical laws are the same in all logically possible worlds.  (Note: constants are laws, so they'd be included.)

What would an alternative be?  To personify a bit, the ingredients would have to "lack modal integrity".  One option would be that how they behave is controlled by whatever laws happen to be present.  On this option, physical laws would be real things that have powers over their ingredients, like gods making the sun shine.  (Or there might literally be gods that make the ingredients do what they do!)  I'd say this is pretty wild.  Another option is that it is brute in one world that, say, x-particles obey the laws in set L, but brute in a different world that x-particles obey laws of some other set L*.  My attitude is to cut out unnecessary brute facts with Ockham's razor, so I prefer the option of individuating ingredients by everything that is true about them.  This way there's no contingency about which laws are attached to which ingredients.  Rather, the appearance of contingency is due to the fact that there are possible worlds with somewhat different ingredients, but when we think of them we often fall into the trap of categorizing them under the same concepts due to their family resemblances.

But, Kris, none of this answers your question.  You want to know whether the physically possible worlds are the same as the logically possible worlds.  That depends.  Of course, all physically possible worlds are metaphysically possible, but many philosophers hold that the metaphysically possible worlds are a proper subset of the logically possible worlds.  In that case, even if the physical laws were the same in all logically possible worlds, nevertheless the physically possible worlds would be a proper subset of the logically possible worlds, not the same set.  On the other hand, if you reject the view that the metaphysically possible worlds are a proper subset of the logically possible worlds, and if you also reject contingencies between ingredients and their laws, then the physically possible worlds and the logically possible worlds are the same set.

Cheers,

James Grindeland


2011-03-23
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
I don't like complicating things, so here is a short answer.
A "world" is said to be logically possible, if it contains no logical contradictions.

A "world" is said to be physically possible, if it doesn't contradict the mosaic of contemporary accepted physical theories.

Thus, logical possibility doesn't have any temporal ingredients: if something is self-consistent, then it is logically possible. Period.

Physical possibility, on the other hand, is context dependent. In particular, it depends on what fundamental physical theories we accept at a given moment of time. What was thought to be physically possible in the Aristotelian-medieval mosaic of theories, should not necessarily be physically possible for the Cartesian, Newtonian or Einsteinian mosaics.

    


2011-03-23
Are the physically possible worlds the same as the logically possible worlds?

Thanks, but that really complicates somewhat. For the following question can be raised. Now suppose a World is physically possible .. i.e. the mosaic of contemporary accepted theories are not violated. But can this world then still be logically impossible ? And what do you mean by logically impossible anyway. 


2011-03-23
Are the physically possible worlds the same as the logically possible worlds?
Hi Hakob

I think this is nicely put.

But there is the additional intriguing question I have raised: Can we talk about ‘possible worlds’ at all now, given that physics now entertains the possibility of an infinite number of universes with ‘laws’ quite different from ours – and, of course, beyond our ken? There may be a world, for example, in which 2+2 = 5, or perhaps where the very notion of addition is ruled out (just to suggest two random possibilities).

As Kim Joris Boström put it neatly earlier in this thread, ‘The word "possible" needs its counterpart "impossible" to obtain any meaning.’ And if, as far as we know, anything is possible…

DA



2011-03-25
Are the physically possible worlds the same as the logically possible worlds?
Hi Hakob,

I essentially agree with you. However, you say
> A "world" is said to be physically possible, if it doesn't contradict the mosaic of contemporary accepted physical theories.
This is similar to what is often heard when, for example, talking about Physicalism. I for my part think that it is a rather problematic construction, because it depends on the vague and volatile notion of "contemporary accepted physical theories" which is afflicted with Hempel's dilemma. Further above, I sketched a different concept of "physical possibility", namely that physical possibility does not exist per se but always and only with respect to some given set of laws, where a "law" is understood in the most abstract sense, namely as a restriction on the set of logically possible worlds. If the set of these laws is identical to the set of laws that apply to our world (whatever they be and whatever we know of them), then the worlds obeying these laws are the physically possible worlds in the stronger sense that you (and others in this discussion) have in mind (I suppose). There can be infinitely many physically possible worlds with laws totally different from the laws governing our world, including elementary constants having different values, and all of these worlds are logically possible. There can also be infinitely many physically possible worlds that obey exactly the same physical laws that apply to our world. (Noting that a physical law does not include the actual state of the physical system under consideration.)
This construction appears to me safe from the discussed inconsistencies and imprecisions, and in particular it is not afflicted with Hempel's dilemma. Also, the set of physically possible worlds is equal to the set of logically possible worlds if and only if it is not subject to any physical law. Besides, Physicalism can then be simply defined by the claim that our world is an element of the set of physically possible worlds with respect to a fixed set of physical laws (whatever they be and whatever we know of them). "To be physical" can then be analyzed as "to obey some fixed set of laws".

2011-03-25
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes
The class of logically possible worlds includes everything that has no internal contradictions. I don't think this is difficult. A simple logical non-contradiction makes the world logically possible. So as long as your imagined "world" (or your theory, if we are to speak properly) doesn't contain any internal contradictions it passes the logical test.   

E.g. Is Avatar's Pandora logically possible? Yes, it is logically (but not physically) possible. It is not quite in accord with our accepted physical theories, since it is easy to show that it doesn't fit our accepted conception of gravity. But the world is logically possible, for I see no internal contradictions in it. We can conceive of such a world, with those unique physical laws. So the world is logically possible, but physically impossible (given to the current state of accepted knowledge). 

So to answer your question: No, if the world is physically possible it is logically possible as well.

2011-03-25
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
I'll try to answer. 

First, it is a common misconception that the contemporary physics "entertains the possibility of an infinite number of universes with ‘laws’ quite different from ours". At any moment of the history of science it is helpful to distinguish between theories that are 
  • accepted (taken as the best descriptions of reality we have at hand),   
  • used (taken as useful calculation tools in practical applications),  
  • pursued (taken as worthy of further elaboration)



So the fact that a theory is pursued doesn't make it accepted, or used. 

E.g. Classical Physics nowadays. Do we think it is useful? Yes, absolutely! We still employ it in engineering, for example. But do we accept it as our best available description of reality? No. We accept Quantum Mechanics and General Relativity. 

E.g. String theories nowadays. Do we pursue them? Yes, we think they are worthy of further elaboration, for we think that the idea is promising. But do we accept any of them? No, because we do not think that we have enough evidence. The accepted position is that they lack experimental confirmation.

This three-fold distinction is useful when we analyse both the history of science and its current state.
 
Now, in our case, all the so-called Many-World quantum theories as simply being pursued, they are not accepted, we do not take any of the existing Many-World quantum theories as the best available description of reality. Nowadays, our accepted theories include the Orthodox quantum mechanics and the Standard model based on it, and General Relativity (together with the theories based on it). And when we speak of physically possible we should only refer to the currently accepted theories.  

As for the mathematical example, yes, there's been a lot of talk about the possibility of 2+2=5, but that is, in my opinion, just nonsense. 2+2=4 is true simply by definition. There can't possibly be a world where this is not so. (Unless you want to change your definitions of "2", "4" and "5", but that would be a question begging.)


2011-03-26
Are the physically possible worlds the same as the logically possible worlds?
Hi Hakob

I did write 'entertains the possibility' (not 'accepts' etc.)  As far as I know that is true.

RE: 'there's been a lot of talk about the possibility of 2+2=5, but that is, in my opinion, just nonsense. 2+2=4 is true simply by definition. There can't possibly be a world where this is not so.'

Well, who knows what might be possible? The very idea of universes utterly different from ours forbids us from making pronouncements like "There can't possibly be a world where ...'. Doesn't it?

DA

2011-03-26
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
Derek,

If something follows from your definitions, it can't be false. Not here, not anywhere else. Because it has ZERO empirical content, it does not forbid anything, it is analytical, for short. 

Example

We define 2 as 1+1.
We define 4 as 1+1+1+1. 

It follows from these definitions that 4=2+2.


This will hold for dragons and cyclops just as well as it holds for apples and planets, simply because it is a proposition that doesn't forbid anything. It will hold come what may. 
I don't see any topic for discussion here. 


What is a topic for discussion, is whether we can think of different universes with different laws of nature (i.e. with different synthetic statements being true). The answer is: yes, we can. 

We can think of a world, where there is no gravity, only repulsion. We can think of a world with no planets or stars. We can think of a world with no philosophizing human beings, for that matter. But this is because such propositions as

"There exists a force of gravity."
"There are planets and stars."
"There are philosophizing human beings."

are all synthetic - they assume something and they reject (forbid) something. There can be worlds where they aren't true.
 
But, again, this doesn't apply to the propositions we simply deduce from our definitions. 

2011-03-26
Are the physically possible worlds the same as the logically possible worlds?
Hi Hakob

Your formulation 'We can think of a world, where..' bothers me. Why should the nature of other universes be governed by, and limited to, what we can think of?

Perhaps, indeed, there are universes in which 2+2 is defined as 5, bizarre though that may seem to us. Perhaps there are universes in which addition itself is impossible. Perhaps anything.

But even if I concede your point, the familiar philosophical proposition 'There is a possible world in which' is still knocked out of court, is it not?  The stipulated conditions are usually empirical in nature - thus satisfying your requirement - and since empirical conditions might now be absolutely anything, the notion of impossible, which would make sense of the idea of possible in this context, is out the window.

Adieu so-called 'thought experiments'. (Thank God!)

D

2011-03-27
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
Derek 

You say "Perhaps, indeed, there are universes in which 2+2 is defined as 5, bizarre though that may seem to us". 

There is nothing bizarre in such a definition, simply because definitions are propositions with no content and they cannot be bizarre. They are simply a matter of agreement - define it as you wish, only be consistent when using it. 

Example.

Consider two systems of mathematics. Let us say that, in the first system, "2" is defined as 1+1. In the other, "2" is defined as 1+1+1. Can we allow this? Of course we can. There is nothing bizarre with the second definition. 

Question: do these two mathematics contradict each other? 

My answer is No, for the two mathematical systems use symbol "2" differently, they mean different things by "2". So there is no contradiction between "2=1+1" of the first system and "2=1+1+1" of the second. Moreover, both systems will hold in all possible worlds (granted that they are self-consistent of course). The reason is that neither system can contradict the results of experiments and observations, for neither contain any synthetic statements, any empirical hypotheses.

It is true that mathematical definitions often change. But it is also true that at any point of time mathematics is a set of propositions where there are basic definitions and all other propositions, deduced from the deifnitions. Mathematics develops both by changing/adding new definitions and by deducing new propositions. The important thing is that at any point of time the system is purely analytical and therefore it holds in this world as well as in any other world. The same goes for our imaginary mathematics where "5" is defined as 2+2. This mathematics too holds in all possible worlds, simply because "5=2+2" is not an empirical hypothesis, but a definition of "5". In this mathematics, when you say "5" you simply mean "2 and 2". 

Another example. Can I take any of the definitions of our current mathematics and change it? Yes, I can. This will give me an alternative mathematical system. But this new system will hold in our world and in any other world simply by virtue of its analyticity. Two systems consisting only of analytical propositions cannot possibly contradict each other, for they do not forbid anything. 

In short, if a system of propositions doesn't contain synthetic statements, if it doesn't forbid anything, it will have zero empirical content and, as a result, will necessarily hold in all possible worlds. 

Anyhow, I suggest we end this discussion here, because I believe it doesn't go anywhere. We've been repeating the same things over and over again.

2011-03-27
Are the physically possible worlds the same as the logically possible worlds?

Hi Hakob

Thanks for your comments.

I don't want to get too strongly attached to the 2+2 idea and its ramifications. My point is simply that once we entertain the possibility that there may be a vast (infinite?) number of universes different from ours, of which we know zero, nada, then philosophical talk of ‘possible worlds’ (and there’s heaps of such talk) seems to become very suspect.

I should add that, in my view, this is no loss whatever to philosophy. The endless science-fantasy scenarios that try to achieve an air of philosophical respectability by calling themselves ‘thought experiments’ have always struck me as a rather juvenile waste of time.

I wonder if we can now look forward to less talk about 'zombies', brains in vats, and so on? I will believe it when I see it.

DA







2011-04-03
Are the physically possible worlds the same as the logically possible worlds?
If the number of possible worlds is infinite would not the isomorphism property between the infinite and the proper subset hold?

2011-04-10
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
This discussion has so widened that it is difficult to engage. All I can do is to offer a suggestion or two in regard to the initial question, which if I understand correctly engages the relation of a logical and a physical world.

Let me make a bold suggestion and suggest that the logical world is merely a construction of mind. The reason is that the mind constructs a representation of the world out of sensations, but  sensory data seem responsive to only one aspect of the world: its intrinsic or local (some would say, observable) properties. If the world consists of processes, then another aspect is surely the real possibilities of things. We learn of these as well, not from phenomena, but from action. Is not the presumption of any action that the world is malleable and has potency? To see the world as self-moving historic entities is realistic, but hardly logical.

Let me also boldly suggest that a projection of real possibilities as multiple alternative worlds removes real possibilities from this world that we index, and this kills this world, reducing its possibilities to static entities, to lifeless fossils. It seems pathologically conservative. This is surely an unpopular view, so I won't pursue it.

When you bring up the question of what were the operative constraints on the constants what underlie the world as we know it, you may open a can of worms. For example, we are not surprised that a living organism ends a functional whole because each constituent has evolved in a way at least compatible with the others and probably contributes to the functionality of the whole. If the constants were initially fuzzy, why not a feedback loop to weed out values that were less compatible with others? In general systems theory, this is called locking in. 

I prefer to think of the constants as possibilities constrained by the properties of things. I think of mathematics as a description, not explanation, and so it can't explain a constant, but only describe it.  As for logic, much in my world is not at all logical, and while imposing localization or closure makes outcomes appear necessary and predictable, I suspect that this is primarily a function of closure, as in the laboratory, rather than de re natura.

As for this "space of possibilites", I fear here an ontological disjunction between possibility and structure, as if one can exist without the other. I prefer to define process as a combination of actuality and possibility, of past and future. Although all reality has access to universal exogenous possibilities arising from the big bang, however it is explained, it is still a structural constraint such as Higgs field, on quantum fluctuation, which are only virtual possibilities, not real possibilities (where "real" here means to make a difference)..

Haines Brown




2011-12-04
Are the physically possible worlds the same as the logically possible worlds?
Reply to Haines Brown
If what is "physical" is described in mathematics, than what is physically possible is contained within the set of mathematical possibilities. However, the set of mathematical possibilities is necessarily larger than the set of physical possibilities, those alternate worlds being constrained by such things as the "consevation of energy" laws. And then again, the set of logical possibilities is not necessarily the same as mathematical possibilities. In short, physical, mathematical, logical, and possible worlds (per Lewis) are not necessarily one and the same. Hope that makes sense...

2011-12-05
Are the physically possible worlds the same as the logically possible worlds?
But what if ' what is physical is not embedded in mathematics.'  What if the two domains overlap at the 'places'  we call general relativity and quantum mechanics?

Perhaps still worse ....what if mathematical construction to physical reality is like being in a country where one can manage to ask for a loaf of bread and some vegetables to survive but cannot talk about high politics?

Where is it written and proved that mathematics embraces all of physical reality and has here or there a region of redundancy?

Han

2011-12-16
Are the physically possible worlds the same as the logically possible worlds?
Ramon, your position is more or less the conclusion I came to in the form that limitless logical possibilities cannot be imputed to an analogous physical system, for a physical system is subject to Second Law.

In my own field, disregard of this can be crippling. A systems approach is almost always explicit or implicit in the work of social scientists in that they rely on a causal relation of entities or the interaction of reified factors or parts that somehow function to support an emergent whole. This forces them to disregard your point in order that they might salvage human freedom and moral responsibility from the fact that all systems (i.e., a complexity framed as an entity , hypostatized as an isolate, or having an initial state defined as entirely observable) are necessarily mechanical and determinant. They are at a loss how to reconcile this with "free will".

This comes up in a remarkable variety ways which attempt to get around the fact that all systems in principle are mechanistic ("open system" is a contradiction of terms). For example, I frequently encounter the chaotic system argument that recursion makes a system is indeterminant. The semantic argument is made that the limitless possibilities for words and their different combinations in different contexts is the basis of human creativity. Also, since system complexity yields unpredictable outcomes because of our epistemological limitations, it is taken to imply that the physical system is itself ontologically indeterminant.  

Haines Brown


2011-12-19
Are the physically possible worlds the same as the logically possible worlds?
Reply to Haines Brown
Jut a silly question: If something is ontological indeterminant (i.e. we do not know its fundamental entities) an it be called a system?

Please give an example of an ontological indeterminant system.

2011-12-19
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes
Meanings in this exchange do not seem well anchored, and so I am compelled to retreat to some basic semantics just to keep my balance.

For one thing, the word "determinant" strikes me as having a range of meanings. For example, it seems it can refer to either a state of being or to a kind of relation, to ontology or epistemology.

As for state of being, it commonly seems to refer to what is the opposite of Absolute or ideal, to what is spatio-temporally contingent or subject to change. It is my sense that the consensus in science today is in favor of an ontological monism, also known as materialism, in that everything is contingent. In this sense, nothing is ontologically indeterminant. For example, in a EM field a measurable value at any spatio-temporal point is an unactualized unequivocal possibility. So this modal possible value is real and determinant. 
 
As a relation, the word determinant often refers to a causal relation, although we then we have to consider whether this might be unequivocal determination or probabilistic determination. More importantly no one really knows what causality is, and so it usually refers to a predictable relation between proximate events, a generalization of experience that lends confidence to predictions. That is, it is epistemological rather than ontological and so irrelevant to your final question.
 
I also have trouble understanding "ignorance of fundamental entities",

a) Ignorance seems a fact of epistemology rather than ontology. That is, can we infer any ontological truth from ignorance except the reality of our own ignorance? (this seems to stand  poor Descartes on his head ;-).

b) I'd be inclined to argue that all things are processes and that hypostatized "entities" are only a hypothetical limiting case. That is, while the hypothetical "entity" may be conceptually useful, it does not actually exist.

c) Further, I have no idea what would make an entity "fundamental". Does this word imply an ontology of systems and hierarchy of levels? If so, I'd be skeptical, for system and level seem only to be methodological tools that at least offer a one-sided distorted  view of things. For example, why is one level privileged as "fundamental" unless it is epistemologically convenient (supports the reductionist explanation suited to hypothetically "closed systems")?

I admit this just raises more questions rather than address your own. So let me try to do that, even though you probably won't care for its presuppositions. An example I'll use for ontological indeterminance is any "process".

I would follow Aristotle somewhat and define process as the union of the modality of possibility and the modality of actuality (this modal realism seems to be the consensus these days in the philosophy of science). Not really unconventionally in substance, I would define this union as the constraint of the probability gradient (usually spoken of as the energy gradient), arising from the improbability of any actual structure, on its possible alternative states  to constitute a probability distribution. If this process enters into union with another (such as measurement instrumentation) there emerges from that union of probability distributions a novel actuality known as a property value. While this does get a little hairy, at least it starts from a scientific consensus over what seem ontologically indeterminant.

If for some reason you followed this paragraph carefully, it returns an ambivalent answer to your question. That is, ignorance (or any other relation of a process) means that its probability distribution in hypothetical isolation lacks actual values and so might be called indeterminant in some sense; actual values are the creation of measurement. On the other hand, isn't a state of pure possibility unconstrained by actuality called a perfect vacuum? If so, a perfect vacuum would be ontologically indeterminant, although it couldn't properly be called a system.

Haines





2011-12-21
Are the physically possible worlds the same as the logically possible worlds?
Reply to Haines Brown
@Haines

Thanks for this thoughtful approach fo my silly question. I appologize for introduction of epistemological terms (knowledge) into the indeterminate. But in a sense indeterminate has it in it to entail knowledge. For something to be 'determinate' there appears to be a 'determinator' necessary. This 'determinator' aquires (has) knowledge while determining don't you agree? Can there be a determination without knowledge. That does not mean can there be a system becomming determinate without me knowing t. It means can there be a system that becomes determinate and it is impossible to know that? If so, how can we talk about it? We need a general principle claiming that it is *necessary* for a system to become from indeterminate to determinate. But the trouble is with 'system' not with 'indeterminate'.

I take it that you mean to say that a vacuum is an example of ontological indeterminant. If so then what vacuum do you mean? A physical vacuum is not indeterminate because we can talk about it and hence have knowledge about it. Moreover, there is no physically passive vacuum (but I make the mistake to talk physics while pretending to do philosophy).

So your vacuum is 'potentiality' without 'actual measured values'.   A kind of 'Copenhagen like' philosophy for quantum mechanics. That is quite a bit metaphysics in a single set of sentences. What about: 'system' is a human construction that works fine is some cases but is 'misleading' in other cases. Like using the word 'witch'. 

If one aims to label 'women that are aiming to be free human beings' and have an excuse to 'eliminate them by fire' (Malus maleficarum) then the word has its (sad) use. However, if one extends it to women flying on a broom at night.... one gets nonsense of a physical sort and have transplanted sad nonsense of a social kind to a field where it will no longer work.

Words are powerful and have their way of misguiding.

2012-02-05
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes
Han,

I apologize for the delay, but have been preoccupied. We are certainly in murky waters here, and I am sad to admit that I have no cogent reply to your points.

Perhaps the word "determinant" refers to a limitation on degrees of freedom. For example, having spatio-temporal location, such as the cat that is presently in the box. While location seems to be an extrinsic property, why is it dependent on consciousness? In simplistic terms, it is a fact that it is in the box whether or not I happen to be aware of it; my death would not liberate it.

But is it a "fact"? A fact is supposedly a statement that has truth value because it corresponds in some necessary way with the state of world, but I don't understand this position. I don't see any empirical relation (correspondence, reflection, model, map, analog) of the electro-chemical state of some neurons in my brain and what's happening outside my head. I'm not at all a skeptic, but I just don't understand the rationale of "truth" value. So my instinct at this point is to use the word "fact" merely to refer to a state of affairs (thus, not a process) whether or not it is linked to any statement about it. I doubt the relation between this objective fact and consciousness is one of "correspondence" and suspect it is instead one of a probability correlation (a complicated point irrelevant in context).

My brain fails me when it comes to simple things. For example, I assume that the belief that the world consists of entities standing in a necessary relation is an artifact of epistemology, and a less one-sided view is that it consists of processes having probabilistic outcomes. If so, "degree of freedom" becomes a measure of probability: the cat is only in the box with a very high degree of probability. So is it still determinate? Often the word determinate is associated with necessity, with unequivocal causality, but it seems that the modern western assumption of an empirically coherent cosmos subject to necessity relies on either neoplatonism or superstition, and is not in accord with the contemporary philosophy of science.

Contemporary philosophy of science accepts a probabilistic determinism, a kind of statistical necessity, in which case perhaps the term determinate remains useful in reference to a process that is not random. But here my brain fails me again. If "random" (as in genetic mutation or radioisotope decay) really means non-contingent or indeterminate, are we not thereby retreating to an ontological dualism? My guess is that events called random are fully determinate, but  unpredictable either because of our ignorance of hidden variables or because predictions of N-body processes far exceed our powers of computation. If so, randomness and in-determination are epistemological artifacts.

Your point about speaking of a vacuum raises a host of other complications. I don't see how our talk or language, or consciousness for that matter, has ontological implications. We can and often do speak of counterfactuals such as unicorns and we know things that escape consciousness (St. Augustine on time, for example). It seems that our engaging the world in action is radically different than engaging it in observation and consciousness. The former engages the real modality of possibility that makes action possible, but the latter only infers just one possibility post facto from its actualization (statistical inference not really an exception), which therefore appears to be a necessity. That is, the necessary and determinate world might after all be an artifact of consciousness and (like "system") a social construct, but the world we engage in action is a probability distribution for property values that are actualized by processes entering a relation.

Haines.  

 
 
 

 

2013-12-16
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
Here is the Objectivist position:  The constants of nature cannot be other than what they are.  There is only one Universe - and only one set of physical constants that describe it.  The Universe is the sum of that which exists - nothing less, nothing more.  Everything that exists has a definite nature.  Mathematics is abstracted from that which exists, and when applied to existents, can only describe that which is. Abstractions that are severed from existents leads the mind into a fantasy world (or worlds).  The fact that one is able of fantasizing doesn't mean the fantasies have anything to do with reality.   Mathematics loses all grounding when the connection to existents is severed, and then the mind will drift without any mooring (see quantum theory). The axiomatic concepts of existence and consciousness, as well as their corollary, identity, cannot be escaped, no matter how much one wishes to erase them. 

2013-12-16
Are the physically possible worlds the same as the logically possible worlds?
Reply to Mark Wilson
RE: "There is only one Universe - and only one set of physical constants that describe it".

I think this assumption is the issue, isn't it?


2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
It is not an assumption in the common way that term is used. All evidence points to it, and there are no facts that contradict it.

What factual evidence is presented that posits the existence of multiple universes?

2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Mathematics describes the physical world, not the other way around.  I can imagine all kinds of things that do not exist, but my ability to think of them is not evidence of their existence.

2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Reply to Mark Wilson
I'm not a physicist, but I gather many of them regard the existence of multiple universes (perhaps an infinite number of them?) as entirely possible. Some might even say probable.

As for "factual" I'm not really sure what the word means in these rarefied areas of physics.

DA

 

2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
It's not the word 'factual' that is the issue, here.  A third grader could understand the meaning of that word.  Rather, it's that philosophers have lost their way and now consider ridiculous ideas emanating from some physicists - such as the possible existence of an infinite number of universes - as 'rarefied'.

2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Reply to Mark Wilson
Ok, not the word " factual " is the issue. But what is ? Please explain the difference between "physical possible" world and "logical possible" world.
Is it like... It is logically possible to have a world where everybody is happy but alas physically this is not possible - e.g. we are mortal and death of a beloved one makes us sad -. I mean, it is logically possible to live in a world without war but physically we just did not do that the past let us say 100.000 years or so.

Or do you mean to say... it is logically possible to have a universe where the speed of light is: 6E8 m/s  but is it physically possible -e.g. there could be a hidden combination between c and h that makes it so that 2c => .5h and at .5h we do not have X particles that are the ancestor to H or He ? No, H, no "me", no "me" hence no question about c and h and.... oh man this is giving a headache. 

2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Reply to Kris Rhodes
It is not physically possible - nor logically possible - for existence to be ANY OTHER WAY THAN IT IS.  The role of logic is to identify that which is.  This requires precise rules of identification, which is the specific task of epistemology.  So the statement that it is logically and/or physically possible that physical constants in nature can be different than what they in fact are - is patently absurd.  This kind of nonsense is only possible when one abandons the axioms of philosophy and wanders about thinking that existence can be anything whatsoever - whether imagined or unimaginable! (Given these arbitrary premises, why leave out the unimaginable?) 

In short, one must make a clear distinction between the primacy of existence (that which is, independent of consciousness) and consciousness, which is the faculty of perceiving that which exists.  Existence has metaphysical primacy.  Consciousness is dependent on existence, and is only possible because their is something to perceive - and in the case of man - conceive.

Logic is the art of non-contradictory identification.  It is a process of consciousness, and as such is completely dependent on two hierarchically interrelated existents - existence (that which is perceived) and man's specific means of acquiring knowledge (conceptualization).

2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Reply to Mark Wilson

The problem is that what a third grader could or could not understand is probably not much of a guide here.  Again, I’m not a physicist but I suspect we’re looking at a changing situation here. Up till now, it’s mostly been the case that a theory becomes fact once it’s proved by experiment. But in highly advanced areas of physics, experimental proof may be too costly to attempt (i.e. bigger even that CERN) or perhaps simply impossible to undertake in practical terms. What do we say then? Suppose a consensus emerges among the world’s physicists that a certain theory about multiple universes is virtually certain to be true but that it’s impossible to undertake an experimental proof of any kind. Do we simply say: “So that clinches the matter: the old idea of one universe must be correct”. That would be a bit head-in-the-sand, don’t you think?

DA

.


2013-12-17
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
Theories are evinced from logic applied to experimental results.  Contrary to what Einstein said, theories are NOT 'free inventions of the human mind' - rather, they are inductions from observations operating within a proper philosophic system. Do you know how the theory of multiple universes arose?  Was it from experimental results?  Were there observations from experiments that suggested the existence of multiple universes?  No - it was more misguided philosophy applied to physics.  Just a further extension of the same ridiculous trend initiated by Bohr and Heisenberg in the 1920s.  Contrary to popular belief, they jettisoned causality long before any observations of quantum energy states were made from experiments.  They had a philosophic position that they wanted to extend into physics. I assume that you are a philosopher, so it is your task to let scientists know when they have gone astray.  Alas, however, without the proper philosophy this is an impossible task.

2013-12-18
Are the physically possible worlds the same as the logically possible worlds?
Reply to Mark Wilson
Hi Mark

I'm not very keen on the formulation that scientific theories are "free inventions of the human mind", whether Einstein said it or not. 'That makes them sound rather like exercises in pure fantasy. They are "free inventions" in the sense that they break free of existing thinking, but they are nevertheless constrained by the phenomena they're attempting to explain. They're not simply forays into science fiction.

As for "it is your task to let scientists know when they have gone astray" I would see this as very presumptuous on my part - even assuming I knew where to start. I'm happy to try to let certain philosophers know where I think they've gone astray, but that's the limit of my ambitions. I suspect any attempt to tell scientists how to think would be met with well-deserved guffaws of laughter. 

Besides, as far as philosophy is concerned, I don't think it makes a huge difference whether there's one universe or one hundred billion.  Philosophy has other, and, for me, more interesting concerns.

DA.

 

 

2013-12-18
Are the physically possible worlds the same as the logically possible worlds?
Reply to Mark Wilson
Dear Mark,

Ok by me if you have strong opinions. I tend to agree but.... YOU CANNOT KNOW!

And I also kind of dislike the big lettertype in a claim. It appears as though you are shouting at the reader. I do not like that.
So:

It is not physically possible - nor logically possible - for existence to be ANY OTHER WAY THAN IT IS.

looks more like ideology than like fact (although I tend to agree with the claim as such).

2013-12-18
Are the physically possible worlds the same as the logically possible worlds?
Reply to Derek Allan
Philosophy is the most fundamental of all the sciences.  It sets the foundation for a view of existence and knowledge.  It is not simply a subjective matter of opinions or a disconnected series of ideas.  Hence it has supremacy over science, and sets the foundation also for ethics and the normative sciences of politics, art and economics.

2013-12-18
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes
Why do you think that you cannot know?  What is knowledge? Is knowledge possible?  If so, how is it attained? Is the universe fully intelligible?  Are contradictions possible? The answers to these questions are VERY IMPORTANT.

2013-12-19
Are the physically possible worlds the same as the logically possible worlds?
Reply to Mark Wilson

Well, this is certainly a big agenda!

Actually, I think one could quite plausibly argue the reverse these days. Perhaps in reality philosophy is slowly dying, killed off by confusion and irrelevance – confusion because it's hopelessly split into two camps in a state of perpetual cold war; irrelevance because outside the cloisters of universities, no one much cares what philosophers think any more.

As for philosophy “setting the foundation” for science, these days, in my view, it's very much the reverse, with (analytic) philosophy running panting along behind scientific advance picking up scraps – and not always with happy results (witness the various contemporary fads for neuro this and that).

As for philosophy setting the foundation for art, don’t even get me started…

DA



today
Are the physically possible worlds the same as the logically possible worlds?
Reply to Han Geurdes
I know a little mathematics (a Masters) and no physics, but I am preparing to read a book entitled "Foundations of Relational Realism: A Topological Approach to Quantum Mechanics and the Philosophy of Nature" by Michael Epperson and Elias Zafiris. Epperson is a philosopher of science and Zafiris is a mathematical physicist.

In that book, as I understand it thus far, the argument is made that the "paradoxes" (such as a multi-verse) associated with QM are the outcome of reliance on set theory. The proposed remedy involves category theory (which, by the way, includes set theory via the Set category).

In preparation for reading (and perhaps understanding) Foundations of Relational Realism I am reading a book entitled "Quantum Mechanics and the Philosophy of Alfred North Whitehead" by Epperson. I know something about Whitehead, having read his (1929) book Process and Reality which is an attempt to integrate quantum mechanics and metaphysics. Epperson suggests that the paradoxes of QM are due to a failure to distinguish between superpositions of potentia (potentia are real but not actual) and superpositions of actual states. The former are thought necessary and the latter are thought impossible. This is the so-called "decoherence" interpretation.