Paul Mawdsley's view of causality in re Objectivism


Roger Bissell

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Ellen,

I sat down to respond to you tonight and realized I owed Roger a response. Now I owe myself some sleep and my family some of my time. I'm sure you understand. I'll respond soon. You may have noticed, when it comes to important issues, I have difficulty writing short responses. Add to this the fact that I read slowly and type really, really slowly, and you can see why I have time management issues.

Briefly though, the three implicit concepts of causation which currently govern physics are:

1) action-to-action causation;

2) entity/field reciprocal causation

3) acausal random event causation

The action-to-action view of causality is at the root of Classical Physics. Action-to-action causation is formalized in Newton’s 3 Laws of Motion as summarised by Asimov (1966):

1) A body remains at rest or, if already in motion, remains in uniform motion with constant speed in a straight line, unless it is acted upon by an unbalanced external force.

2) The acceleration produced by a particular force acting on a body is directly proportional to the magnitude of the force and inversely proportional to the mass of the body.

3) Wherever one body exerts a force on a second body, the second body exerts a force on the first body. These forces are equal in magnitude and opposite in direction.

In the interests of defining the behaviour of entities in a manner suitable for mathematical formalism, what things are, identity, is abstracted or subtracted out. The behaviour of entities is defined in terms of ACTIONS, and ACTIONS interacting with ACTIONS. That is, causality is implicitly defined in terms of actions, and actions interacting with actions. The mathematical formalism at the base of physics requires the abstracting-out of identity from entities to reduce them to quantities. This is what leads to the causal bias in modern physics.

Oh well, I wrote more than I planned. As you have seen before, my enthusiasm has overwhelmed my discipline. Now I am really tired. But its worth it.

Thanks,

Paul Mawdsley

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Didn't we have 3 discussion threads under Metaphysics before the software change. I have some vague recall of having several cycles of a discussion of whether we knew the mind to be completely a system of classical physics determinism with Dragonfly and Paul, primarily. This somehow grew out of a post about energy in a system of entities. B)

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The point of view, that the identity of an entity determines it's actions, has clearly some problems in the light of modern physics (general relativity and quantum mechanics).

General Relatvity explains that the cause of the motion of bodies in free fall are determined by the gravity field, the geometry of spacetime, which itself is detemined by the distribution of mass/energy in space.

Now what is in this case the entity that is responsible for the action (the motion of a free falling object), it is clear that it is not the object itself. The gravity field on the other hand is not a limited object and for that reason identity can not be applied to it.

In quantum mechanics experiments with entangled particles, the point of view that the observable phenomena would be determined by the identity of the particles themselves (wether at a given time those could be observed or know, or not), would lead to an explenation which is known as local hidden variable theory. It has been shown/proved that no hidden variable theory can explain the outcomes of experiments.

From that point of view also one needs to doubt the very concept of 'identity' of some entity.

I think it is a rather subjective (that is: human centered) notion of reality, and not part of objective (material) reality itself. If we side with objective material reality and side with rational sciences, clearly we see that this point of vision can not be sustained by reason.

Apart from this, the Heizenberg Uncertainty principle already disclaims that we can ever know the 'true' identity of an entity with exactness.

A vision that is cling on to the idea that objects and entities would have some absolutely fixed (ie. immutable) identity, although such a vision has some relative meaning, is not well equipped for dealing with the reality of the material world in which everything changes and evolves and in which nothing is fixed.

It has no explenatory power to explain how the world evolved from a state in which only the lightest elements (hydrogen, helium, lithium) existed into a world full of other material organisation forms, from stars, galaxies to planets to living things to humans, etc.

In so far it is true that object or entities have entities, it is also true that there is opposition within such an entity, that is, an object or entity is at any given time equal to itself but also in opposition with itself, which is nothing else as saying that this object/entity is in the process of change, development, etc.

That is true for objective material reality as a whole, it is true for the world of living organisms, and it is true for the world of humanity, both in terms of social organisation and productive forces and on the mere individual level.

There is nothing mystical about the idea that everything is subject to change and development, it is in fact the only rational point of view.

Edited by heusdens
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Roger:
My own understanding about possible objections to Big Bang theory is that since you can't get something from nothing,

Why not?

I've also heard Objectivists argue convincingly that the universe is eternal, that there can't have been a time prior to which anything existed.

The fact that there can't have been a time prior to which anything existed does not imply that the universe is eternal, it's perfectly consistent with a finite-time universe. Now the Big Bang theory describes the situation after the first 10^-35 sec. What happened in that first period we don't know, neither do we know if there was a "before" the Big Bang or not; all theories about that are still speculations. But the Big Bang theory for times after the first 10^-35 can be tested, and if you want to reject it, you'll have to come up with scientific arguments and not with philosophical speculation. There is a parallel with the theory of evolution: this can be tested without having a theory about abiogenesis. The latter may be an extension of the theory of evolution, but it's not necessary to prove the validity of that theory.

The vision that the Big Bang theory states that everything emerged from a singularity is put simply: wrong.

Although this point of view has been popularized by the media, it is a simple fact that the Big Bang theory does not state that, it is not the subject of the Big Bang theory itself to state anything about the origin of the universe.

[ Compare this with evolution. The evolution theory is a theory about how life evolves from simple organisms to more complex organisism, but the evolution theory itself does not state anything about how the first life form developed or even what was the first living organism. That subject is simply not the scope of the theory of evolution, but strictly lies outside of it's domain. The subject field that does try to answer this question is abiogenesis. ]

Same for the Big Bang theory, the subject of how this very small, hot and dense 'fireball' or cosmic soup of particles (although the world particles in this state is inadequate because at these energies a vacuum is indistinguishable from particles) is not part of the Big Bang theory at all. The Big Bang theory simple explains how the universe evolved since then, how it cooled, expanded and became larger, etc.

Important aspects of the Big Bang theory is that it decribes how this very small, dense and hot initial stage of the universe developed, how the fundamental forces of nature (gravity, strong nuclear force, weak nuclear force and electromagnetic force) condensate out of this enormous energetic early stage, how the known particles condensate out of this, etc. Already in the first three minutes of the universe, many things happened which have been studied in detail and for which particle accelerators that are able to reach these enormous energies can shed some more light on, leading to these so called 'Grand Unified theories'.

The understanding of what the Big Bang theory in fact states or not states, has been messed up for the popular understanding of it. Unfortunately this is not only due to the fact that some well known physicist adapted a doctrine, in which it was explained that the singularity is literally the start of everything (spacetime and matter/energy emerging from a singularity), and that there was no "before". Amongst others Sir Roger Penrose made this point of view popular, but currently he has abandoned this point of view, since most cosmologists nowadays have abandoned this point of view.

This point of vision is both from a meta-physical point of view and from a physical point of view WRONG.

The metaphysical point of view is that matter in motion is itself indestructable and uncreatable. Time and space have no independent existence from matter itself. The emergences of matter, motion space and time from literal nothing would thus be something impossible.

For the physical explenation, one has to see that the singularity is a hypothetical point in spacetime (quite literal the 'begin' or 'edge' of spacetime) that emerges from a mathematical formalism, which are the Einstein equations. (The first to solve the Einstein equations which was the first indication that later lead to the Big Bang theory, was the Russian mathematician Alexander Friedman, which showed that there were only two solutions to these equations: either a universe that collapses onto itself, or one that expands).

Singularities (or infinities) are not only occuring in general relativity, but also Newtonian gravity has such 'singularities'. Take the well known formula of Newton for the forceof gravity (F = G m M / R^2) and you already see that if two point masses touch each other (R is the distance becomes zero) it would give rise to an infinite force, a singularity.

In reality however such never happens, for two reasons: 1. masses or not realy points but take up space and 2. at short distances the repulsive electromagnetic force takes over.

General Relativity however is known to be incomplete, and in fact the occurence (in the theory, the mathematical solutions of the equations) of the singularity in fact means that General relativity predicts it's own breakdown. For the cosmological scales in the universe, this is not a problem, since it can predict what happens without contradictions. Near the singularity however general relativity can not predict what happens. A complete understanding in terms of predictability has to be based on not only general relatvity but also quantum mechanics. In (almost) all other circumstances we can use either one of these two fundamental theories (with the exception of a black hole in which also these theories need to be taken together).

The first approach to explain what happens near this hypothetical point of the singularity was made by the Soviet scientists Starobinsky, who developed a theory about quantum gravity in order to explain the Big Bang. A short time later, the American scientists Alan Guth (a particle physicist) hooked on some similar ideas indepedently from Starobinsky when studying the behaviour of matter/energy in a vacuum (states which are called "true" or "false" vacuum, depending on wether the potential field is at it's minimum or not). Although the first models (based on quantum tunneling) did not work (they would leave the initial state of the universe in a too messy state, which is ruled out by observation), this was a breakthrough in understanding the early universe, and which lead to a seperate theory for understanding how the Big Bang came about, which was coined Inflation cosmology. The central principle of inflation is that a tiny patch of false vacuum surrounded by a true vacuum expands exponentially fast due to the fact that it excerts a repelling force of gravity. Within a fraction of a fraction of a second (10 to the power minus 32 seconds) this very tiny patch grows to enormous size.

A major part of the development of inflation cosmology into a realistic theory was done by Andrei Linde.

The achievement of this work that he shows that inflation can occur in a chaotic state of the initial universe (thus eliminating the need for special initial conditions), and that once inflation has started it goes on eternally, creating ever more new universe bubbles, and which theory is termed the chaotic eternal inflation.

Although inflation itself is an ever ongoing proces, a typical universe undergoes inflation only a tiny amount of time. After that, the inflation field decays, and reheats the universe (when the inflation field whobbles near it's minimum of the potential) and releases it's energy in the form of all the baryonic matter. After inflation ends, the universe expands in a more moderate fashion. The age of our universe in fact is the age of the universe since inflation ended.

The theory of cosmological inflation is still under development, and their are various models (different models based on different fields or combination of fields). So far this theory looks good because it makes predictions which on observational grounds can be ruled out, but so far inflation theory stands the test, and which explains why many cosmologists adapt inflation theory as an explenation for the Big Bang.

The importance of inflation theory that needs to be stated is that without inflation a number of facts could not be explained.

First there is the fact that the universe on large scales is (as is observed) very near to flat (that is Euclidean: parallel lines do not cross) instead of either positively or negatively curved. General Relativity allows for both positively and negatively curved spacetime.

This fact can be brought back to the issue of the average density of the universe, which must be very near to omega critical (the criticial density of the universe. A larger density would lead to a universe collapsing, a lesser density to a universe expanding eternally).

In fact, without inflation, the fact that the value of omega (the average mass/energy density of the universe) is so near to omega critical is something of a miracle, because any tiny deviation from the value of omega near the first fraction of a second, would have lead to a huge deviation now, into a universe that either would have collapsed long ago, or into a universe which was already smeared out totally and with nothing to be seen.

Inflation explains this because inflation drives the density of the universe nearer and nearer to a value of omega critical. Moreover, inflation theory predicts the universe to be enormously bigger then what can be seen, many times greater then the horizon.

Second there is the so called horizon problem, which means that different parts of the universe, which could not have been in thermal contact, are in almost perfect thermic equilibrium.

Also this can be explained in terms of inflation because it allows for the universe to start out in thermic equilibrium and during inflation spacetime grows that fast that it passes the horizon (which in fact means that this happens faster then the speed of light, which is not in contradiction with relativity because that only refers to things in spacetime) and which explains that regions now far apart in space are in thermic equilibrium.

Third there is the homogeneity of the universe, which means at large scales (far larger then galaxy) the universe is homogeneous. In fact that is not the only thing that needs to be explained, since at smaller scales there are in fact inhomogeneities (stars, galaxies, galaxy cluster and superclusters, which are seperated by large voids -- a large scale model of the universe looks somewhat like bubble soap, the interiors of the bubbles represent the voids, and near the edges of the bubbles , where bubbles touch each other is the concentration of matter in the form of superclusters and clusters and galaxies) which also needs to be explained.

Both facts can be explained at the basis of inflation, because the universe started out very small and homogeneous, which grew in a very short time to enormous proportions. The inhomegeneities are explained at the basis of quantum fluctuations, which formed the initial 'rimples' in the early universe that seeded galaxy formation in later times.

In fact the very precise prediction that could be made at the basis of inflation theory of these quantum fluctuations, which could be tested for in the cosmic microwave background radiation (the oldest relic of the early universe that can be observed, which formed after the universe cooled down significantly so that atoms could be formed and which made the universe transparent to light), is a strong part of the observational evidence that backs up inflation theory, and why it is accepted as the standard explenation for the Big Bang.

A fourth point for which inflation gives an explenation is the so-called 'monopole' problem (a monopole would be a particle with magnetic charge, just like there are electric charges). According to high energy physics and grand unified theories monopoles would have to been formed also from this immensely hot and energetic soup, but they are not observed at all. Inflation explains that at the basis that either these monopoles were thinned out so immensily that they are very seldom indeed, or that in fact the whole universe (the bubble that came out of inflation) is one monopole and that we in fact reside within a monopole.

Some interesting side notes:

Inflation theory now exists for about 25 years, and it shows great explenatory power in telling something about the universe, and makes predictions that can be tested and so far are in good condition with observational evidence.

Apart from inflation there are different models that try to explain the Big Bang. For instance string theory or M theory has it's own scenario that explains an ekpyrotic scenario at the basis of colliding branes (branes in M theory are multidimensional surfaces to which open strings are attached).

I have not looked into M theory and ekpyrotic much, since string theory is field of study on it's own. For instance, string theory would come with the idea that there is not one unique true vacuum state, but a huge number of them, and all different, invoking in fact different form of physics very much different then the physics in our own universe.

Some different attempt has been made by Hawking, Turok and Hartle, who made a (mathematical) model based on instantons, which form the 'begin' of spacetime and form themselves into a universe.

The metaphysical problem with this is however that the instantons themselves can not be explained, there is no 'before'. Although such is indeed a metaphysical curiosity, for physical sciences it only matters wether such a model can or can not explain the observations. Physics makes no a priori metaphysical assumptions in that respect.

Some objections to it (by Linde) were that these models can be ruled out based on observational evidence.

I don't know the current status of instantons, wether or not this theory is still developed or has been abandoned.

A majority of cosmologists and physicists accept the inflationary scenario at the basis of it's observational evidence and explenatory power, and has become the standard theory in this field.

From a metaphysical point of view, at least it sounds a more satisfying explenation then models which incorporate the idea of a finite past.

In general though the resolution of metaphysical issues (eternity/infinity of space time and so forth) at the basis of physics is difficult and near to impossible, since also in inflation the issue can be stated wether or not inflation is past eternal. In theory it is potential past eternal, but investigations show that it supposedly is not past eternal. What happened before inflation? And before that? These are eternal questions that remain, and for which only metaphysics provide answers. But they are untestable assumptions.

So far I can say, there is no reason (based on cosmology) to ever doubt the idea that spacetime and matter/energy isn't eternal and infinite, and a barrier which once was there in theoretical assumptions about the Big Bang and how it originated, in fact have been removed and are sufficiently grounded, so I have no doubt that any new barrier that might come up, could also be removed.

But then, also on the same metaphyscial grounds, there is no possible way in which all of eternity can be known, so in fact it isn't an absolute.

A metaphysical ground for seeing that is that the maxim of existence (the maxim of all objective relations in the material world taking to it's ultimate limit) is itself something that can not be objectively there (it would already incorporate everything and anything, and therefore there would not be anything strictly outside and apart of it on which it existence could be objectively grounded). To assume that is to assume an absolute, for which there is absolutely no objective ground.

Some interesting sources about cosmological inflation:

http://www.lifesci.sussex.ac.uk/home/John_Gribbin/cosmo.htm

http://www.stanford.edu/%7Ealinde/1032226.pdf

http://www.stanford.edu/~alinde/

http://en.wikipedia.org/wiki/Cosmic_inflation

And an astronomy/cosmology primer, that has an excellent page explaining the Big Bang theory for the beginners:

http://www.astro.ucla.edu/~wright/cosmolog.htm

Edited by heusdens
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Heusdens, nice overview of current inflation theories. But I disagree with the following:

This point of vision is both from a meta-physical point of view and from a physical point of view WRONG.

The metaphysical point of view is that matter in motion is itself indestructable and uncreatable. Time and space have no independent existence from matter itself. The emergences of matter, motion space and time from literal nothing would thus be something impossible.

It's far too early to say what theory about the origin of the Big Bang is wrong or not, in that regard all theories are still highly speculative. And if physics can't tell us, metaphysics certainly can't tell us anything about it. For example, where does metaphysics get the notion that matter (in motion?) is indestructable? It can only come from empirical evidence, which is the domain of physics. And in fact matter is not indestructable, as we learned a century ago. It's true that mass-energy is still conserved, but the ancient notion that mass is indestructible is just wrong. Further the total energy of the universe may be equal to zero, so conservation of energy isn't necessarily in contradiction with creation ex nihilo. Anyway, below the Planck limit, and that's where the Big Bang starts, all bets are off as the usual laws of physics no longer apply.

From a metaphysical point of view, at least it sounds a more satisfying explenation then models which incorporate the idea of a finite past.
But who is interested in metaphysical viewpoints? I'm only interested in facts.
So far I can say, there is no reason (based on cosmology) to ever doubt the idea that spacetime and matter/energy isn't eternal and infinite, and a barrier which once was there in theoretical assumptions about the Big Bang and how it originated, in fact have been removed and are sufficiently grounded, so I have no doubt that any new barrier that might come up, could also be removed.

The notion of a finite time in the past is far from discarded, whatever the current favorite theory may be. As I said, such theories (not the theories about what happened during the big bang, although these are still far from definitive, but at least they are in principle testable) are highly speculative, so the jury is still out, and probably for a long time.

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Heusdens, nice overview of current inflation theories. But I disagree with the following:

This point of vision is both from a meta-physical point of view and from a physical point of view WRONG.

The metaphysical point of view is that matter in motion is itself indestructable and uncreatable. Time and space have no independent existence from matter itself. The emergences of matter, motion space and time from literal nothing would thus be something impossible.

It's far too early to say what theory about the origin of the Big Bang is wrong or not, in that regard all theories are still highly speculative. And if physics can't tell us, metaphysics certainly can't tell us anything about it. For example, where does metaphysics get the notion that matter (in motion?) is indestructable? It can only come from empirical evidence, which is the domain of physics. And in fact matter is not indestructable, as we learned a century ago. It's true that mass-energy is still conserved, but the ancient notion that mass is indestructible is just wrong. Further the total energy of the universe may be equal to zero, so conservation of energy isn't necessarily in contradiction with creation ex nihilo. Anyway, below the Planck limit, and that's where the Big Bang starts, all bets are off as the usual laws of physics no longer apply.

Perhaps the notion that matter is indestructable/uncreatable is a misunderstanding, since the philosophical meaning of the word 'matter' is slightly different then that in physics.

If you refer to the physical meaning of matter, you are clearly right.

The early stage of the Big Bang or inflation comes with the concept that 'matter' in the ordinary sense of the word (in the form of subatomic particles and stuff) did not yet exist. Whatever was there at these hight energies was even indistinguisable from vacuum.

There were no particles or whatever. In inflation theory, all particles of the current universe emerged after reaching the minimum of the potential and the release of the energy of the potential field.

Matter in the philosophical sense is not something specific (it is a catagory of thought, of all there is in objective material reality outside, apart of and independent of the mind). What matter is is up to the material sciences to define.

Anything the physicsts builds their model on of what physical reality consists of, is matter in the philosophical sense.

The conservation of matter/energy is not something that has get rid of, only that the physical theory about what constitutes matter/energy has changed. Quantum mechanics nor general relativity nor inflation cosmology nor (I suppose) M theory/superstring theory gets rid of those conservation principles, only the way it is defined might depend on the underlying theory.

In respect to the universe, the idea that the total matter/energy contents might be zero. In fact one could - for good reasons - have the point of view that the universe in total has no physical attribute at all.

Since by definition there is nothing outside the universe, it can not have any of such physical properties.

By definition there isn't anything to measure any such physical properties.

So in fact one could not even state that (in the absolute sense) there is a universe instead of none. We can't state anything about all of material reality (the whole universe, in whatever form it may exist) in an absolute way.

There is only objective material existence within the universe. Relative to us - our existence - other things exist. And for all practical and theoretical reasons, that is the only thing what matters.

From a metaphysical point of view, at least it sounds a more satisfying explenation then models which incorporate the idea of a finite past.
But who is interested in metaphysical viewpoints? I'm only interested in facts.

Are you arguing that a metaphysical position that explains the universe as the creation of a deity, as long as it explains the same facts, goes as well?

So far I can say, there is no reason (based on cosmology) to ever doubt the idea that spacetime and matter/energy isn't eternal and infinite, and a barrier which once was there in theoretical assumptions about the Big Bang and how it originated, in fact have been removed and are sufficiently grounded, so I have no doubt that any new barrier that might come up, could also be removed.

The notion of a finite time in the past is far from discarded, whatever the current favorite theory may be. As I said, such theories (not the theories about what happened during the big bang, although these are still far from definitive, but at least they are in principle testable) are highly speculative, so the jury is still out, and probably for a long time.

Physics, like I explained, doesn't have an a priori viewpoint on this, except that it might be clear that physics can not explain what comes out of an unexisting physical state. Physics explains only how an existing material state changes into a different one. So if you try to defend that it is a 'possibility' that the universe emerged from nothing at all (an inexistent material state) then that view can not be upheld by physics, but that is a metaphysical position. And in fact a metaphysical position which is undefendable.

Some point however needs to be clarified, regarding infinity itself.

Imagine a line (a mathematical abstract we are all familiar with) without ends.

Place any two points on the line. Independent of where you place these points, the distance between this two points will always be a finite distance.

However, since we defined that the line itself has not an end, it is clear that wherever we placed the points, we will always be able to place them further apart.

That is what in fact the infinity of the line is, it is the posibility for those two points to be placed further apart, no matter where you put these points. The reasoning behind that is that of mathematical induction, and that is the way the infinity of the line can be proved.

In no case however can you ever measure the infinite, because that alltogether incorporates the wrong idea about infinity (which for instance the dialectician Hegel calls 'bad' infinity), since an infinity which is totally absorbed, is a contradiction in terms. The reality of the infinite is that it can not ever be absorbed completely.

Edit: Note also that such a invalid idea about what the infinite is, has been used wide over in all kind of different contexts, and lies amongst others behind the Kalam cosmological argument that supposedly 'proofs' that time supposedly had 'begun' sometime.

The argument runs in this fashion: suppose that time had no beginning, then it follows that already an infinite amount of time should have been elapsed, which is a contradiction and hence, time can not be infinite and must have had therefore a begin.

The whole error of this argument lies in the fact that supposedly one started counting at some point on this eternal time line, and counted back from there to now. But wherever one starts the count, this does not matter, since on the infinite time line, this means one already leaves behind an infinite amount of time.

This is a famous falacy, because the argument already assumes that what needs to be proven namely that such a point exist at all from which one can start the count. Since the time line is infinite, by definition there is no point on which one can start counting in the first place, and for that reason the above argument is invalid.

Since the argument makes use of the impossible fact that such a point (from which one supposedly starts the count) exists, it already rejects the idea incorporated in the infinity of the line, that such a point could exist in the first place.

Edited by heusdens
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Further the total energy of the universe may be equal to zero, so conservation of energy isn't necessarily in contradiction with creation ex nihilo.

Could you say a bit more about that comment? I don't understand how the total energy of the universe might be equal to zero.

Ellen

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Further the total energy of the universe may be equal to zero, so conservation of energy isn't necessarily in contradiction with creation ex nihilo.

Could you say a bit more about that comment? I don't understand how the total energy of the universe might be equal to zero.

Ellen

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Ellen,

This was a speculation made by Stephen Hawking in his book "A Brief History of Time". He suggested that, in answer to the problem of how all of the energy of the universe could arise ex nihilo from the big bang, perhaps the total energy of the universe is zero. As I recall, his suggested explanation was that the universe has negative potential energy associated with all of the matter being gravitationally bound. The negative potential energy could be exactly equal to the positive energy of all the matter/energy in the universe, so that the total energy would be zero. To me, this kind of thing is so wildly speculative that it is more in the realm of metaphysics than physics.

Martin

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Further the total energy of the universe may be equal to zero, so conservation of energy isn't necessarily in contradiction with creation ex nihilo.

Could you say a bit more about that comment? I don't understand how the total energy of the universe might be equal to zero.

Ellen

___

Ellen,

This was a speculation made by Stephen Hawking in his book "A Brief History of Time". He suggested that, in answer to the problem of how all of the energy of the universe could arise ex nihilo from the big bang, perhaps the total energy of the universe is zero. As I recall, his suggested explanation was that the universe has negative potential energy associated with all of the matter being gravitationally bound. The negative potential energy could be exactly equal to the positive energy of all the matter/energy in the universe, so that the total energy would be zero. To me, this kind of thing is so wildly speculative that it is more in the realm of metaphysics than physics.

Martin

Um. Larry thinks that Hawking made some basic errors, but I don't know enough to specify the details. The above explanation doesn't make sense to me, just reading it as stated. It sounds like a mathematical supposed "fix." But I don't know if that's what Dragonfly was talking about.

Ellen

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Ellen,

This was a speculation made by Stephen Hawking in his book "A Brief History of Time". He suggested that, in answer to the problem of how all of the energy of the universe could arise ex nihilo from the big bang, perhaps the total energy of the universe is zero. As I recall, his suggested explanation was that the universe has negative potential energy associated with all of the matter being gravitationally bound. The negative potential energy could be exactly equal to the positive energy of all the matter/energy in the universe, so that the total energy would be zero. To me, this kind of thing is so wildly speculative that it is more in the realm of metaphysics than physics.

Martin

What Stephen Hawking in fact describes in "A Brief History of Time" is that one should reflect on this 'singularity' as just a point on a sphere, like any other. It is like the Northpole, when standing there, the only direction is south (the direction that represents time).

Some see in this an argument for saying that time is finite and started at the singularity. A number of physicsist - amongst others also Sir Roger Penrose - adapted at some time this point of view and popularized it (but Penronse now abandoned that vision, and most cosmologists now agree on inflation as the standard explenation of the Big Bang, although the scientific and cosmological debate still continues).

But watch very closely at what Stephen Hawing in fact say, because most people only read one part of it, and forget about the other part. Stephen Hawking talks in "A Brief History of Time" not about just one axis of time, but two axis of time: one real and one imaginary (the terms real and imaginary relate to their meaning in mathematics, and relate to complex numbers which have two terms, a real part and an imaginary part. The imaginary unit is the square root of minus one).

He mentions therefore that while the universe looks in one axis of time (the real axis) finite in extend, in the other axis (the imaginary) time is however not finite but eternal. Stephen Hawing adds to that that the imaginary time axis is "more real" as the real time axis. So in fact he does not argue that time is just finite, that is a one-sided approach.

[ Side note: complex numbers are just a mathematical tool for doing calculations in physical theories, it is used widespread in physical theories, like electronics and quantum mechanics. One should abstrain from the meaning of the words 'real' and 'imaginary' in their ordinary (daily language) use, as something unphysical or unreal or something. ]

I added this just to explain that how the general public understands something, and what it in fact means physically, are often two seperate things. This explains to a large extend how all kinds of misrepresentation of scientific theories enter the world, and kind of have a life of their own, while they don't relate to what the scientific understanding says.

In fact if one realy wants to know what these theories say and not say, one has to understand the underlying mathematical theory and the strange notions it incorporates for instance about the topology.

[ Side note: topology is the study of abstract spaces with quite different properties as our ordinary concept of euclidean space. Topological spaces may incorporate quite contradictionary ideas, like a space with a finite boundary or surface, but an infinite interior. ]

In general those formulations are so abstract and require such an enormous mathematical and topological understanding, that it is near to impossible to explain it in ordinary language.

But in between the lines, physicists make it clear also for the layman what he means.

Stephen Hawking for instance in "A Brief History of Time" makes clear that "physicists do not know how to make physical law from 'nothing'".

That means in other words that a physicist, when explaining something physically, always proceeds from a known physical state in which there can be a description of space, time and matter/energy, and in no way can a physicist explain something without that. No advancement in physics ever can change that position.

In fact that is the most sound argument ever to tell anyone that a metaphysical position that would resemble something as "everything coming from nothing" can not ever be based on physical theory. And that is the precise reason such metaphysics should be put in the garbage can.

Since in the metaphysical sense we can make sense of the universe, and can readily reject the notion of creation ex nihilo, in fact (unless one wants to become a cosmologist) that is what one needs to take in mind, and forget about all these speculate notions (which the not-scientific educated have a hard time to understand what it realy means anyway) which dwell around in cosmological theories.

A proper (metaphysical) understanding of the universe is that it has no boundary or edges, so for that reason, it can't have a point of begin or a bounding edge in any other sense.

In the layman notions that just says the universe is infinite and eternal, although it is not eternal/infinite in the trivial sense (the euclidean absolute flat spacetime) since that - combined with the cosmological principle, luminous matter distributed homogeneously through the universe - would invoke Olbers' paradox.

The best way to think about it is that the universe is an eternal process unfolding in space and time, not limited by anything, and in that sense is eternal and infinite.

Your argument that metaphysics is not important, the only things important are facts, I do not agree on.

Facts in themselves are quite useless without a proper understanding of reality, and to make sense of reality one already must have some metaphysical understanding about reality.

Facts only mean something in the context of a proper theory about reality and having a metaphysical understanding of reality.

In fact out brain does that (mostly un- or subconsciously) all the time, since without that, how to make sense of all the sensory perceptions? They would just be meaningless facts if they had no interpretation on what happens in the outside world.

For example, look at these graphics. The brain interprets this as motion, but in fact there is no motion at all!

Although it is certainly true that our interpretations can be wrong some times, this does not mean that our basic assumptions about reality are wrong or untrue.

Edited by heusdens
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I looked up Hawking's book to find the exact passage. Here it is, from "A Brief History of Time", in the chapter entitled "The Origin and Fate of the Universe":

"The idea of inflation could also explain why there is so much matter in the universe. There are something like ten million million million million million million million million million million million million million million (1 with eighty zeroes after it) particles in the region of the universe that we can observe. Where did they all come from? The answer is that, in quantum theory, particles can be created out of energy in the form of particle/antiparticle pairs. But that just raises the question of where the energy came from. The answer is that the total energy of the universe is exactly zero. The matter in the universe is made out of positive energy. However, the matter is all attracting itself by gravity. Two pieces of matter that are close to each other have less energy than the same two pieces a long way apart, because you have to expend energy to separtate them against the gravitational force that is pulling them together. Thus, in a sense, the gravitational field has negative energy. In the case of a universe that is approximately uniform in space, one can show that this negative gravitational energy exactly cancels the positive energy represented by the matter. So the total energy of the universe is zero."

In the next paragraph, Hawking goes on to quote Guth, the founder of inflation theory. Hawking writes, "As Guth has remarked, 'It is said that there's no such thing as a free lunch. But the universe is the ultimate free lunch.'"

So Hawking is arguing that the creation of the entire universe ex nihilo from the big bang does not violate conservation of energy, since the entire universe has zero energy.

Martin

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Martin,

I didn't see your post until today. I've been busy talking about music and literature and AR on other threads, and I'm far behind reading the heavy threads. Just a quick comment on something in the material you posted from Hawking's A Brief History of Time:

"But that just raises the question of where the energy came from. The answer is that the total energy of the universe is exactly zero. [....]"

[....]

So Hawking is arguing that the creation of the entire universe ex nihilo from the big bang does not violate conservation of energy, since the entire universe has zero energy.

I can see a problem in what he says without needing to be a physicist. It's sophistic. He's switched from using "zero" as meaning "nothing" to using "zero" as meaning a result of mathematical cancellation. Whether what he proceeds to say about positive and negative energy makes physics sense, needs a physicist. But I don't see that he's said anything convincing about "creation ex nihilo." Nor is it my understanding that Big Bang theory requires "creation ex nihilo." I thought the typical thing said was that we just don't know what was there prior to when time as we think of it started.

Ellen

___

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Martin,

I didn't see your post until today. I've been busy talking about music and literature and AR on other threads, and I'm far behind reading the heavy threads. Just a quick comment on something in the material you posted from Hawking's A Brief History of Time:

"But that just raises the question of where the energy came from. The answer is that the total energy of the universe is exactly zero. [....]"

[....]

So Hawking is arguing that the creation of the entire universe ex nihilo from the big bang does not violate conservation of energy, since the entire universe has zero energy.

I can see a problem in what he says without needing to be a physicist. It's sophistic. He's switched from using "zero" as meaning "nothing" to using "zero" as meaning a result of mathematical cancellation. Whether what he proceeds to say about positive and negative energy makes physics sense, needs a physicist. But I don't see that he's said anything convincing about "creation ex nihilo." Nor is it my understanding that Big Bang theory requires "creation ex nihilo." I thought the typical thing said was that we just don't know what was there prior to when time as we think of it started.

Ellen

___

Ellen,

I have no idea if the physics makes sense or not. It certainly seems strange to me. In my studies of physics, I learned that potential energy is relative, not absolute. That is, the potential energy function is not an absolute quantity but is always defined with respect to an arbitrary reference. If this is the case, it makes no sense to say that the gravitational potential energy is exactly equal to but opposite in sign from the energy associated with the matter in the universe, since the gravitational potential energy could only be defined with respect to a reference and not as an absolute quantity.

I agree that the big bang doesn't really require "creation ex nihilo". I think Hawking was trying to answer the question of where all the energy of the universe came from. If one thinks about the vast amount of matter and energy contained in billions of galaxies across the universe, the idea that all of this energy could come from a singularity is really pretty bizarre. But I certainly agree that, if the big bang theory is indeed the correct explanation for the existence of our universe, it is simply not known what happened prior to the big bang or what actually caused the big bang to happen. Big bang cosmologists would be the first to admit this.

Martin

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  • 1 month later...

The poster writes:

I emphatically disagree with Dragonfly's assessment of the importance or value of the Law of Causality. (He is welcome to dispute this and to clarify his own view.) I think there is a lot we can do, as philosophers of science wielding Rand's metaphysical insights as a kind of "veto power" over invalid models of physical and psychological reality. As a relevant example, indeterministic models of physics (or psychology) that claim some actions are not caused but just happen, must be false.

I reply:

There are only two "veto powers" concerning a physical theory:

a. An internal logical inconsistency.

b. A properly designed experiment which shows that a prediction of the theory is false.

There are your vetoes. Collision with one's philosophical predispositions do not count. Only facts count.

Ba'al Chatzaf

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I've also heard Objectivists argue convincingly that the universe is eternal, that there can't have been a time prior to which anything existed. They also argue that there can't be a place outside of which anything exists. This sounds like they are saying the universe is infinite, but it also sounds like the idea from cosmology that the universe is finite but unbounded. (Whatever that means.)

REB

Here is what it means. Let T be a topological space and S be a subset of T. p is boundary point of S if

and only if every neighborhood of p contains a point in S and and point not in S.

Now consider the surface of a three dimensions sphere. This a a two dimensional topological space where the

neighborhoods are defined by "circles" around each point on the surface of the sphere. A neighborhood of p is the set of points whose great circle distance from p is <= r where r is less than the great circle distance between antipodal points. Under this definition, no point on the surface of the sphere is a boundary point. But the distance between any two points must be less than or equal to the distance between any pair of antipodal points. This makes the surface of the sphere -finite-. Hence the surface of the sphere is both finite and unbounded (no boundary points on it).

It is a technical term requiring some grasp of basic point set topology. I hope you find this useful.

Ba'al Chatzaf

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