Can we speak intelligibly about non-physical entities?

[Ionian_Tradition]

To borrow from Hempel's dilemma, to posit "Physicalism" one must first provide a comprehensive definition of the term "physical". If one asserts that the term "physical" refers to that which is revealed through the various scientific theories which encapsulate our contemporary understanding of the "physical" world (quantum mechanics, general relativity, atomic theory, etc), one has failed to provide an adequate definition of the the term "physical" given that our contemporary understanding of the physical world is demonstrably incomplete. An example of this would be the fundamental conflict existing between the theory of relativity and quantum theory which presently drives the search for a "Grand unified theory". If one asserts that a future "complete physics" will round out our understanding of the physical world in its totality, one has appealed to a circular form of reasoning which states that all phenomena are explicable in terms of physics because a proper understanding of physics is that which explains all phenomena (including abstract thought, which begs the question that abstractions can be understood in terms of physics). Moreover, if one attempts to define the term "physical" in reference to a physics yet to be developed, has one truly said anything meaningful given that one cannot truly know what new physics will emerge? A cursory review of scientific developments made over the course of our species' history does not instill confidence that our "physics of the future" is guaranteed to reflect a physics similar to physics as it is presently known.

Given this, how is it that we can speak intelligibly of "non-physical" entities given that the term itself implies the understanding of that to which the term is antithetical ("physical" entities)? We have seen that we do not yet, and may never, possess a comprehensive understanding of the term "physical", how then can we speak intelligibly of things which are the opposite of that which has yet to be properly defined?


Questions for debate:

1. Can the term "physical" be comprehensively defined so as to provide meaning to the term "non-physical"?

[asymptotic freedom]

Divine Insight wrote:

And that's going to be totally different from what we currently think of as being "physical". So we may as well be prepared now to refer to this new realm as being a "non-physical" realm.

Why call it "non-physical"? Even if multiple space dimensions exist, as both Many Worlds and String Theory claim, why should they be any less "physical" than what our feeble brains see around us now?

What about virtual particles which pop into existence out of nowhere and then vanish, leaving no trace? Where do they come from? Where do they go? What happens to their mass and energy? I have read that QM allows all this to happen throughout the universe around us by saying that such particles exist for such a short time that the laws of physics can't catch up with them. Really? Reeealy? The Heisenberg Uncertainty Principle can't be sure they really exist, so ignores them?

On the science section of the board there is a thread, "can something come from nothing", an exchange between me and another poster dealing with this very issue.

[Divine Insight]

Divine Insight wrote:

And that's going to be totally different from what we currently think of as being "physical". So we may as well be prepared now to refer to this new realm as being a "non-physical" realm.

Why call it "non-physical"? Even if multiple space dimensions exist, as both Many Worlds and String Theory claim, why should they be any less "physical" than what our feeble brains see around us now?

I wasn't talking about merely extra dimensions of space. If such extra dimension exist they would indeed qualify as being "physical" just like the other dimensions.

What I was addressing was a realm where the laws of "physics" are so radically different that it would be basically paradoxical to even refer to them as being "physical". For example, the concept of non-locality which requires a total abandonment of our normal understanding of "cause and effect".

If such a realm exists, why bother to continue to call it "physical"? That would just be an attempt to stretch the semantics of the term "physical" to apply to anything, (i.e. even things that no longer obey the laws of "physics" that describe our universe).

I mean, sure, it's all just semantics in the end. We can try to get more semantic mileage out of the term "physical" by re-defining it in new ways. But when does that become impractical? How many things does the term need to refer to before it virtually becomes a meaningless term.

I'm personally inclined to believe that when we finally enter this new realm of investigation we are going to recognize that it's so radically different, that we're basically going to have to view it as a "Whole new type of physics". So much so that we would only be doing ourselves a favor to refer to it as something "other" than the physical world that our normal ideas of physics currently apply to.

We'll probably end up coining a new term for this aspect of reality. I doubt very seriously that we will officially name it "non-physical". We'll come up with a different term for it altogether. But until that happens, we may as well refer to it as being "non-physical" right now, for lack of a better term.

What about virtual particles which pop into existence out of nowhere and then vanish, leaving no trace? Where do they come from? Where do they go? What happens to their mass and energy? I have read that QM allows all this to happen throughout the universe around us by saying that such particles exist for such a short time that the laws of physics can't catch up with them. Really? Reeealy? The Heisenberg Uncertainty Principle can't be sure they really exist, so ignores them?

To begin with it's actually sad that this kind of phrasing was introduced. These particles don't actually "pop into existence OUT of nowhere". They don't "come" and "go". Instead they become manifest, and non-manifest. That may seem like a trivial thing, but it's not.

It is also often said that they "borrow" energy from the universe at large. But that too is misleading. They don't "borrow" anything. They "ARE" energy fluctuations of the universe at large.

Keep in mind E=mc

These particles don't "come" from anywhere. They are manifestations of energy.

The world that governs their behavior is indeed itself a "non-physical" world.

It's non-physical, super-luminal, and is driven by strange things like complementarity, entanglement and instantaneous superpositions that know no bounds in terms of distance or propagation delays.

So in a very real sense this "non-physical" realm can be viewed as "pure information" of sorts. Information that is not restricted by the standard "laws of physics" that we are used to. It's driven by the strange concepts I just mentioned above in ways that we cannot understand in terms of physicality.

Yes, one could "argue" from a purely philosophical point of view that this should still be considered to be "physical" in a sense because it's still related to the existence of the physical universe as a whole. But the problem with that demand is that it misses the point. It misses the importance of non-locality, complementarity, entanglement, superposition and the instantaneous "sum over histories" effects.

Calling this behavior "physical" may have some philosophical merit, but as a practical matter is basically useless semantics. It certainly wouldn't refer to the same kind of "physical entities" that we normally associate with with 'physical objects.

This would be more like Plato's "abstract mathematical world". Or "the mind of God" if you will. And it would work totally outside of the confines of restrictions of the speed of light, or even what we deem to be reasonable "cause and effect".

Yes it is "cause and effect" in a way. But it's an instantaneous type of "cause and effect" where it makes no difference what you call the "cause" and what you call the "effect" because there is no difference between them. Sequential time that we associate with the "physical world" no longer applies here.

And that's a big indication right there why we shouldn't continue to call it "physical" as a practical matter.

[JohnPaul]

Divine Insight wrote:

And that's a big indication right there why we shouldn't continue to call it "physical" as a practical matter

.

OK, I won't call it physical, but I will call it part of a larger unified reality. It certainly is not "supernatural" or "wholly other." Maybe "hypernatural?"

I looked at your posts with ThatGirlAgain in the other forum and was very impressed. My knowledge of such things is purely amateur and I lack the math to follow it very deeply. Math was always easy and intuitively obvious to me in high school, and elementary calculus later was easy for me too, but I bogged down in differential equations and never went any further.

I hope to see a big breakthrough in physics soon, similar to Einstein's relativity a century ago, which will make things clear again.

John

[Ionian_Tradition]

What? Who "hopes" that our current scientific understanding will prove wrong?

Anyone who is still clinging to an idea that physics can move beyond Quantum Mechanics. That's "hope" that is not supported by current modern "science" because Quantum Mechanics is current modern science.

That one is hesitant to issue the rather brazen claim that our scientific understanding of the "physical world" is now fully complete, is not a desire that such should not be the case. You're conflating prudent humility with subjective preference.

Care to substantiate this claim by citing a source?

The Heisenberg Uncertainty Principle. (a mathematical relationship that is part of Quantum Mechanics)

And this substantiates your claim how exactly?

Skepticism regarding QM's capacity to describe the physical world in its totality, especially in light of its present incompatibility with General Relativity, is not an unscientific desire to see QM fail.

Perhaps not from a philosophical point of view, but as a practical matter it is.

Besides, maybe it's General Relativity that's incompatible with QM, did you ever think of that? After all, QM is the most successful theory in all of science.

Imagination and skepticism are essential to scientific inquiry. As is a rejection of the strict philosophical dogmatism you wish to adorn in the guise of a robust science. All truths in science are tentative, ever ready to shift in accordance with the advent of new and compelling evidence. In science we always leave the door open for new findings which may serve to revise, or overturn, long cherished theories. That you wish to close the door on the prospect of acquiring a deeper understanding of the physical world than can be presently encapsulated within our current scientific model is quite telling. The only one really "hoping" for something around here seems to be you my friend.

With that said, GR and QM are mutually incompatible. So yes, GR is incompatible with QM as is QM incompatible with GR. This is precisely why we seek a unified theory.

Skeptical/critical examination of any scientific theory is science at work.

Using that ideal, you're basically handing "spiritualists" and "supernaturalists" a silver platter proclaiming that they are indeed "doing Science" by refusing to accept current scientific knowledge in the hopes that they can move beyond it.

I doubt spiritualists and supernaturalists will win a scientific consensus by merely rejecting presently established theories. It hasn't worked thus far. If we are to perhaps move beyond QM it will be done through the acquisition of evidence. Not stubborn rejection of QM on mere theological grounds.

I'm not sure I ever argued that such a thing must be accomplished in a manner conducive with Classical physics. Where did you gather that I did?

You implied it when you compared our present day knowledge with previous eras of science and suggested that we moved forward from those ideas so why can't we do it again.

The reason we can't do it again is precisely because of the Heisenberg Uncertainty Relationship (or the discovery of complementarity as Neils Borh prefers to call it).

So for you to suggest that we could just keep plugging along like we did back in the days of Classical Physics implies to me that you don't fully understand why that principle no longer holds.

How does the Heisenberng uncertainty principle demonstrate that we have nothing left to learn about the physical world?

I personally believe that it not only can be, but that it already is sufficiently defined via the mathematics of Quantum Mechanics. Granted, a definition that may not be readily accessible intuitively to the man on the street. Or any non-mathematician, for that matter.

{snip}

Having said all of the above, if we then allow the mathematics of Quantum Mechanics to "define" precisely what we deem to be "physical", then clearly there must exist a "non-physical" reality beneath the "physical world".

This "non-physical" reality would only be "non-physical" in the very precise sense that it simply cannot be described by "physics" or any laws of "physics" that we can determine. And in that sense it makes perfect sense to speak of the "non-physical" as still being "real" and having obvious properties and behavior that we can know exists, but cannot define precisely in terms of "physics".

I've already given my "working definition" of what I define as "physical" based on science.

If you wish to contest that, so be it. But then please offer your own definition of what you consider to be "physical". Otherwise your very question has no meaning.

Your definition is predicated upon the rather dubious notion that our modern conception of physics is the end of the line. You've yet to substantiate that claim. My own definition of the term "physical" has traditionally been "That which possesses structure, or that which possesses the capacity to exert force upon structural entities." I'm still considering whether or not this is an acceptable definition of the term.

I'm actually appealing to Quantum Mechanics (our current most successful scientific mathematical description of what we mean by "physical" yet)

Therefore I have a very precise definition of what I mean by "physical" and therefore I can speak in an intelligent way about 'non-physical' entities. Entities that most likely exist because they have an affect on our physical reality, but cannot themselves be considered to be "physical" by our current scientific definition of what we mean by 'physical' according to physics, (i.e. Quantum Mechanics).

You've not demonstrated that QM is an accurate description of the physical world in its totality, and I'm not sure how you'll do so without appealing to a priori presumptions. Therefore I'm not convinced your definition of the term "physical" escapes Hempel's dilemma.

There you go again charging me with appealing to Classical Physics when I've done no such thing. Please stop misrepresenting my position by disingenuously asserting that I do not recognize the distinction between Quantum and Classical physics. Never have I argued that we require a classical or conventional method of investigation in order to further our understanding of the physical world. The very fact that QM is distinct from classical physics denotes that a classical understanding of physics is not the "end all" in terms of advancing our scientific understanding of the universe at large. With that said, it is somewhat presumptuous to assume that, given our incomplete understanding of even the quantum world, QM is itself the "end all" in regard to our understanding of the physical world.

But that was precisely what the Einstein/Bohr debates were entirely about.

"Can a Quantum-Mechanical Description of Physical Reality Be Considered Complete?"

They both wrote papers using precisely this same title.

Einstein said, "No", while Bohr said, "Yes".

In fact, Bohr argued that the Heisenberg Uncertainty Principle (or the principle of what Bohr calls "Complementarity" demands that it necessarily must be complete. At least complete in the sense that it is as far as we can ever go.

Einstein's objections were based on his suspicion that "hidden local variables" could potentially be discovered at some point to further our understanding of QM.

However, John Stewart Bell changed all that with "Bell's Theorem", which was experimentally testable, and fell in favor of Borh, and proved that Einstein's "hidden local variables" could not be used to further explain QM.

And that's where we stand today.

In other words, we stand at a point where QM must be "complete" in the sense that we can never know more about the nature of the "physical" world than we already know.

That's where we are right now.

Some people appeal to String Theory as possibly going beyond this, but even String theory doesn't truly promise to go beyond this. All string theory does is accept QM and promise to potentially describe General Relativity in terms of QM.

But even that promise has never been realized to day. So far it's just an empty promise. But even if it did come to pass, it wouldn't have made any progress deeper into the mysteries of QM.

~~~~

I'm not trying to misrepresent your position at all.

I'm just trying to respond to your question, "Can we speak intelligibly about non-physical entities?".

I can, because I have very methodically defined what I mean by "physical" by simply accepting QM as a final mathematical definition for that. Therefore when I consider potential processes beneath the quantum level I can meaningfully refer to those processes as being "non-physical" and rightfully so. Because when speaking of processes in the realm, the laws of "physics" go out the window.

For one thing we move from a "local" environment (i.e. an environment governed by the speed limit of light), to a "non-local" environment (i.e. an environment where there are no propagation delays (and thus no conventional classical sense of "cause and effect").

A very strange realm to be sure, and thus deserving of being called "non-physical" IMHO.

Yet, we have very good reasons for believing that such a non-physical realm exists.

Just like John and I were discussing,... even if that ends up requiring "Many Worlds". Although I personally feel that there are even better pictures to be had, like the picture proposed by David Bohm and make almost "intuitive" by Richard Feynman independently via his insight into his concept of "Sum Over Histories".

Anyway, I'm not even remotely attempting to misrepresent you. I was addressing your notion that we should be able to just "Keep on plugging along as before". That's what appears to be "Classical thinking" to me.

QM says, nope, we're done from that local perspective. To "move forward" requires a whole different perspective (i.e. a non-local perspective).

And that's going to be totally different from what we currently think of as being "physical". So we may as well be prepared now to refer to this new realm as being a "non-physical" realm.

This doesn't escape Hempel's dilemma. Though QM has won a certain measure of our confidence, there are no guarantees that the QM we know and love today will not change with the advent of new discoveries. We cannot know a priori that QM has found it all when we cannot conclusively say that we know all of what there is to find in the first place.