What makes physics feel like magic?

[Loren Booda]

What physics seems to you most like magic?

 

[wuliheron]

Quantum Mechanics of course.

 

[elas]

visualize the beauty that is physics
We witness the microworld and macroworld
create a responsible and ethical philosophy of physics, testable yet not malicious

I have a problem with the way you use words. We do visualise physics by building a model that gives correct predictions, but how do we "witness" same?
If a theory is testable it is no longer a philosophy, it is a science; QT is a philosophy, atomic physics is a science, particle physics is linked to QT for the same reason ie it is 'visualized' not 'witnessed'.

 

[quantumdude]

If a theory is testable it is no longer a philosophy, it is a science; QT is a philosophy,

Why, because it can't be "witnessed"?

atomic physics is a science,

When's the last time you "witnessed" an atom?

particle physics is linked to QT for the same reason ie it is 'visualized' not 'witnessed'.

And atomic physics is linked to QT as well. In fact, both atomic physics and particle physics are applications of QT.

 

[elas]

And atomic physics is linked to QT as well. In fact, both atomic physics and particle physics are applications of QT.

Only in as far as QT is able to predict events. The following references illustrate the limit of current knowledge-

"They (physicists) feel a complete explanation of the subatomic world will not have been attained until it is known why particles have the charge, masses and other particular properties they are observed to possess”.
Richard Morris in "Achilles in the Quantum Universe”

But it is not just a question of “why particles have particular properties” but also a question of “what are the particular properties” as illustrated by the following quotes:

The measured mass of the particle is a result of the motion of the initially massless “particle” in an external field. Although this idea appears to be very attractive it is not possible, at the present time, to build a complete theory on this basis. Certainly the quantum effects must be taken into account. But even within the framework of quantum theories the nature of the mass of the particles remains unexplained.ELECTRODYNAMICS AND CLASSICAL THEORY OF FIELDS AND PARTICLES by A.O. BARUT, Professor of physics, University of Colorado (1964 revised by author 1980)

“Quantum physics is about ‘measurement and statistical prediction’. It does not describe the underlying structure that is the cause of quantum theory”.
"Quantum Physics, Illusion or reality” Alastair I.M. RAE of the Department of Physics at the University of Birmingham

Extract from Encyclopaedia Britannica
Philosophical status of scientific theory
Philosophical analysis and scientific practice
"The arguments about these rival ontological and epistemological views cannot be safely left or judged without first looking more closely at the complex relationship between the general analytical interests of philosophers and the more specific intellectual concerns of working scientists themselves. For the degree to which each view about the reality of scientific entities and facts can carry conviction depends substantially on what branches of science are at issue. As the focus of philosophical attention has shifted historically from one scientific terrain to another, so, too, have the relative degrees of plausibility of these rival positions varied.
Since the 1920s, for instance, there has been a marked revival of philosophical discussion among scientists working in several specialized fields—particularly, among physicists concerned with the structure and development of quantum mechanics. In epistemic terms, the statistical character of quantum-mechanical explanations has prompted some fundamental questions about the status
and limitation of human knowledge.

Note that these statements apply to particles, atoms are not mentioned, my understanding of the reason why atoms are omitted is that the larger atoms are observable to a degree acceptable as proof of existence (but not their internal structure).

 

[Locrian]

You must not know how those atoms are "observed" then, because it is entirely through quantum mechanical processes. Trying to make atomic physics a science without including quantum mechanics as a science is highly inconsistent.

 

[quantumdude]

And atomic physics is linked to QT as well. In fact, both atomic physics and particle physics are applications of QT.

Only in as far as QT is able to predict events. The following references illustrate the limit of current knowledge-

No, what illustrates the limit of current knowledge are journal articles and textbooks. Have you consulted either?

"They (physicists) feel a complete explanation of the subatomic world will not have been attained until it is known why particles have the charge, masses and other particular properties they are observed to possess”.
Richard Morris in "Achilles in the Quantum Universe”

Guess what? Atomic physics doesn't explain that either.

You're flip-flopping here. First, you say that QT is a philosophy (as opposed to a science) because "it can't be witnessed". Of course, that statement is nonsense because QT is not a "thing", but I assume that you mean the objects brought under the study of QM cannot be witnessed. But now, you are citing the fact that QM can't answer certain questions, which is a different issue altogether. Make up your mind!

In any case, you aren't even addressing my point: atomic physics is just an application of QT, just as particle physics is. Feel free to consult any elememtary textbook on atomic physics to see that.

I'm skipping over the next several paragraphs, as they are totally irrelevant.

Note that these statements apply to particles, atoms are not mentioned, my understanding of the reason why atoms are omitted is that the larger atoms are observable to a degree acceptable as proof of existence (but not their internal structure).

You are wrong. Atoms are quantum mechanical systems. You can't validly infer that they are not just because they aren't mentioned in an entry on subatomic physics in (of all things!) the Encyclopedia Britannica.

 

[Loren Booda]

elas, my signature was not part of my original post. Sorry for the confusion - but thank you all for your responses!

To me, witnessing requires consistent acknowledgment (measurement) of and participation with physical phenomena, the latter especially propounded by J. A. Wheeler.

 

[Les Sleeth]

What physics seems to you most like magic?

I am not sure I'd call it "magic" as much as mysterious or confounding when there is no plausible explanation for why something exists a certain way. With relativity, for instance, one ends up just saying "that's how it is." There is no way to explain "why" relativity is so counterintuitive. Lots of things in physics are like that, from simple particle charge and the constancy of light speed to where all the energy-mass of the universe came from. I think those of who tend to believe that ultimately everything makes sense are most disturbed by things that don't seem to have a logical explanation.

But if you want us to choose what is MOST magical-seeming, then I'd have to say the organizational quality of physics found in biology.

 

[elas]

Trying to make atomic physics a science without including quantum mechanics as a science is highly inconsistent.
No, what illustrates the limit of current knowledge are journal articles and textbooks. Have you consulted either?
Stephen Hawking (A Brief History of Time) is only the latest of many leading physicists to point out that QT is not a science but a mathematical predicting hypothesis, others ad the term ‘philosophy’. In the introduction Hawking gives his opinion of what constitutes a theory, I have ‘consulted’ this and other books. Now for the intelligent reply.

To me, witnessing requires consistent acknowledgment (measurement) of and participation with physical phenomena, the latter especially propounded by J. A. Wheeler.

Would you agree that these measurements are of mass, charge and energy and that all three are hypothetical names; in that case you are using ‘magic’ as a replacement for ‘hypothetical? Barut, in respect of mass, used the phrase “scientist believe” leading some SSK experts to claim that QT was more akin to religion than to science.

I will do some homework on Wheeler, your recommendations on books or papers would be appreciated.

 

[Loren Booda]

Magic relates to circumvention of "natural philosophy" (physics) by supernatural beliefs. Magic involves unfounded belief, rather than support by scientific method. For instance, the Sun's light had been explained by various superstitions and myths, and even "magical" scientific models (that the Sun was driven by conventional combustion) which did not incorporate all of the necessary facts. Once the phenomenon of fusion was established, solar science became real as opposed to just supernatural.

 

[Loren Booda]

elas,

My library only holds Wheeler's books on Gravitation (Misner, Thorne, and Wheeler), A Journey into Gravity and Spacetime and At Home in the Universe. My ability to write is impeded, so no long-winded arguments, please, but your interest is appreciated.

Rather than your definition of "hypothetical" I would use the concept "fundamental," and yes, we require some measure of faith to realize them (concepts) as such. Whether this is magical thinking or primarily psychological relies on the justification by future physics.

 

[Adam]

What physics seems to you most like magic?

The bit that makes sunrises and sunsets, or makes a girl smile, or makes a girl feel really nice. :D

 

[Les Sleeth]

Magic relates to circumvention of "natural philosophy" (physics) by supernatural beliefs. Magic involves unfounded belief, rather than support by scientific method. For instance, the Sun's light had been explained by various superstitions and myths, and even "magical" scientific models (that the Sun was driven by conventional combustion) which did not incorporate all of the necessary facts. Once the phenomenon of fusion was established, solar science became real as opposed to just supernatural.

Really? How will you justify establishing natural philosophy as the standard against which supernatural beliefs are judged? Do you think natural philosophy is immune from its own "magical" beliefs? Consider how the "magic" of consciousness is now pooh-poohed by functionalists who already believe, far in advance of the evidence they need to have such confidence, that physical processes can explain consciousness. How about those scientists who now "dismiss" vital force as unnecessary to a life theory, but who cannot even come close to demonstrating how physical processes can achieve something living. I say, they believe in physicalist magic every bit as much as the religious believe in spiritual magic.

Magic, to me, is either fun tricks, or the horse hockey any belief system conjures up to explain away the gaps in their theories.

 

[elas]

Rather than your definition of "hypothetical" I would use the concept "fundamental," and yes, we require some measure of faith to realize them (concepts) as such. Whether this is magical thinking or primarily psychological relies on the justification by future physics.

Leading physicist (Barut, Hawkings, Penrose, Feymann et al) state that the model used to explain the mathematics of QT is a hypothetical model hence the definition is not mine. (If the model is hypothetical, then surely all terms peculiar to that model are also hypothetical).
Before delving deeper into your articles,I am trying to ascertain whether you subscribe to the current school of thought which states that somethings are and will remain, beyond explanation, in non-hypothetical terms; or do you hold out some hope that a non-hypothetical interpretation will be found one day?
If the former then the universe is magical, or miraculous; if the later, then the universe is an evolutionary product subject to scientific (i.e. non-hypothetical) explanation. Either way the universe is truly amazing.

 

[Loren Booda]

elas,

They are right, in my opinion, that QM as it exists is a hypothesis, or perhaps more so, a mathematical construct.

I wonder if any instantaneous equation, rather than one of process itself, can describe the physical "structure" behind quantum mechanics. The reality which reveals the probabilistic nature of the wavefunction may disallow its explanation in terms of a global model. That is, there may always remain an incompleteness, call it complementarity, probability, uncertainty, participation, wavefunction collapse, superluminal signaling or entanglement, which allows for the infinity of interpretations toward QM.

 

[hypnagogue]

Before delving deeper into your articles,I am trying to ascertain whether you subscribe to the current school of thought which states that somethings are and will remain, beyond explanation, in non-hypothetical terms; or do you hold out some hope that a non-hypothetical interpretation will be found one day?
If the former then the universe is magical, or miraculous; if the later, then the universe is an evolutionary product subject to scientific (i.e. non-hypothetical) explanation. Either way the universe is truly amazing.

The physical interpretation of the mathematics of physics will always be hypothetical. For any given mathematical structure, there are multiple ontological frameworks that can generate (or are consistent with) the math. Principles such as Occam's Razor help us choose what seems to be the framework that most likely matches the math, but there's no final authority on the matter.

This does not imply, however, that the universe is not subject to scientific explanation. The formalisms of physics are not hypothetical. The interpretations of the formalisms are, but by necessity. No method will reveal to us, with certainty, the actual underlying framework of the universe; the best we can hope to do is infer it, whether we use science or not. Science just happens to be the most apt tool with which we can make such inferences.

 

[Locrian]

Stephen Hawking (A Brief History of Time) is only the latest of many leading physicists to point out that QT is not a science but a mathematical predicting hypothesis

By definition of the scientific method, QT is not a hypothesis, but a theory. It is therefore a mathematical predicting theory, which is most certainly a science. You should go back to basics and look more carefully at what defines science in the first place; it will aid you in determining the difference between theory and hypothesis.

 

[balkan]

loren, you claimed that you cannot interact with nor sense atoms and their constructs... are you serious? of course you can!

 

[Loren Booda]

balkan,

loren, you claimed that you cannot interact with nor sense atoms and their constructs... are you serious? of course you can!

Please remind me where I said just that.

 

[elas]

I wonder if any instantaneous equation, rather than one of process itself, can describe the physical "structure" behind quantum mechanics.

'SciAm' did a special issue on the need for a new theory. Hawking (BHOT) devotes several pages to the issue going as far as defining the rules for a new theory. Feymann implied in his lecture on electromagnetism that in his opinion a new theory was impossible. Richard Morris lists those things we do not know. Newton, Einstein and some recent writers are on record as believing that the final solution will be “a thing of great simplicity” (Newton’s words).
My contribution has been banned from PF and all threads mentioning it have been closed. I would not want to see this thread closed so I will go no further here, instead I am going to continue that fight on ground of my own choosing.
As to your original question I would say that the universe is not a product of some magical act, but it is an amazing, awesome, astounding product of infinity and that the method of its production is there to be understood together with the knowledge of each individual part, waves are of course, part of the answer, but a long way from being the whole answer.

 

[quantumdude]

I feel that Loren Booda is someone I might be able to have a debate with, but Tom is more interested in arguing or dissagreeing rather than given logical reasons for his statements and I need to separate the two.

You post such outrageous falsehoods that I am compelled to disagree.

And just because you can't understand the reasons for my disagreement, doesn't mean that I don't post them.

Stephen Hawking (A Brief History of Time) is only the latest of many leading physicists to point out that QT is not a science but a mathematical predicting hypothesis, others ad the term ‘philosophy’. In the introduction Hawking gives his opinion of what constitutes a theory, I have ‘consulted’ this and other books. Now for the intelligent reply.

What are you expecting? That book is not a textbook, nor is it a journal article. It's a watered down pop science book intended for laymen, and your quote does not do one thing to bolster your disagreement with either myself or Locrian. In fact, it does not address either of us in the slightest.

I pointed out real falsehoods in your statements, and a real inconsistency in your reasoning. You said that atomic physics is science and QM is not. The only statement you offered in support of that is that QM can't be witnessed. I informed you that atoms are not witnessed any more than QM phenomena, and I further informed you that atomic processes are QM phenomena.

As both myself and Locrian have told you, atomic physics is quantum mechanics. It it quantum mechanics applied to electrons moving in an Coulomb potential.

And your reply? "You just like to disagree, rather than present evidence. Hawking said..."

Pfffft...

 

[elas]

Tom
Of all the professional citicisms of BHOT I have read, I cannot recall one that agrees with your point of view, can you refer to one?
Your comments on particle physics and QT are open to question but as they do not get to the core of out dissagreement let that be put aside for the time being.
At present we know nothing about the internal structure of fundamental particles. (I give a reference to support that statement). QT is a hypothetical model whose accuracy is not in question. I quote Hawking as the latest (but by no means the only) physicist to point out the need for a theory that explains what the entities used in QT really are, and why they exist in their particular quantities.
One can not explain the cause of entities in a hypothetical model by using the hypothesis itself, but by arriving at the same conclusion as the hypothesis using a different route.
To this end I have taking data from the hundreds of experiments listed by the Particle Data Group and arranged the data in a mathematical manner that explains why particles have some (but not all) of their particular properties.
In as far as I have gone I have attempted to provided a bridge between what is found by experiment and what (I am happy to concede) is a brilliant predicitve model.
In order to avoid this thread being closed, like all the other threads on this subject, I would prefer that you use your authority to transfer our dissagreement to a new thread or alternatively we can agree to dissagree. I have stated my intention to continue the struggle on grounds of my own choice (away from censorship), but would be happy to have a reasoned debate on 'what constitutes a theory' and/or the value of my contribution.

 

[quantumdude]

Tom
Of all the professional citicisms of BHOT I have read, I cannot recall one that agrees with your point of view, can you refer to one?

Please elas, get real. The reason you cannot find a professional criticism that says that Hawking's book is a watered down reference for laymen is because that is supposed to be obvious. Professional reviewers would not think to mention that the book is not to be used as a substitute for a textbook in physics, because that too is supposed to be obvious.

And when I ask if you have consulted a textbook or journal article, it is supposed to be obvious that a reference to Hawking's pop science book is not satisfactory.

Your comments on particle physics and QT are open to question but as they do not get to the core of out dissagreement let that be put aside for the time being.

My comments on particle physics and QT were simply that particle physics is an application of QT. That is not open to question. Feel free to consult any elementary textbook on the subject (hint: not Hawking). Try Halzen and Martin, Griffiths, Frauenfelder and Henley, or Huang.

At present we know nothing about the internal structure of fundamental particles. (I give a reference to support that statement).

No kidding. That's why we call those particles "fundamental"! If we knew their structure, we would call some other particles "fundamental".

QT is a hypothetical model whose accuracy is not in question.

I regard this statement as a self-contradiction. A hypothetical model is a model that is assumed. QT was a hypothesis. But as you correctly note, its accuracy is well known. That means that it is no longer assumed, and therefore no longer hypothetical.

I quote Hawking as the latest (but by no means the only) physicist to point out the need for a theory that explains what the entities used in QT really are, and why they exist in their particular quantities.

But you don't even understand what you are quoting. There is a progression of "quantum theories" that becomes ever more sophisticated. It goes from quantum mechanics, to quantum field theory, to strings. If you were to ask Hawking, you would find that the theory he describes is quantum theoretic. The answer is not to abandon QT, the answer is to embrace it.

One can not explain the cause of entities in a hypothetical model by using the hypothesis itself, but by arriving at the same conclusion as the hypothesis using a different route.

Of course, any theory is going to have unexplainable elements. This is an inevitable consequence of the fact that the universe is known a posteriori. I don't know why you will not let go of your notion that the universe is known otherwise.

But you can be assured that any theory--yours included--will of necessity axiomatically contain fundamental, primitive, unexplained degrees of freedom. You are seriously deluding yourself if you think otherwise.

To this end I have taking data from the hundreds of experiments listed by the Particle Data Group and arranged the data in a mathematical manner that explains why particles have some (but not all) of their particular properties.
In as far as I have gone I have attempted to provided a bridge between what is found by experiment and what (I am happy to concede) is a brilliant predicitve model.

Where is the model? I've checked your website as recently as last week, and it was not to be found.

In order to avoid this thread being closed, like all the other threads on this subject, I would prefer that you use your authority to transfer our dissagreement to a new thread or alternatively we can agree to dissagree.

Tell you what: First post the theory on your website. As of now, no real theory is displayed there. If I think that it has merit, then I will open a thread on it myself in the Nuclear and Particle Physics Forum.

I have stated my intention to continue the struggle on grounds of my own choice (away from censorship), but would be happy to have a reasoned debate on 'what constitutes a theory' and/or the value of my contribution.

As far as "what constitutes a scientific theory", I am in agreement with Popper: A theory is scientific if it is contingent. That is, it must be both confirmable--and most importantly--falsifiable.

QM qualifies as a scientific theory in this sense, and you have not provided any reason to think otherwise.

 

[elas]

Loren Booda

Sorry to attract my antagonist to this thread. To avoid further outburst, I will settle for the Hawking definition that QT is a 'scientific hypothesis'.
I disagree with the use of words like “miracle, belief and magic” because they imply that some acts are both beyond explanation and perhaps, attributable to a personal power. I regard magic and miracles as a measure of our ignorance and possibly some other persons greater intellectual and/or scientific abilities.
Perhaps we can move on a step. What are your views on the particle/wave nature of fundamental particles? Are quarks and leptons particles, waves, or both at the same or different times?

 

[Loren Booda]

I think the subatomic wave-particle nature is well established, but may be difficult, if not impossible, to humanly interpret in a deeper sense. Measurement establishes the observed complementary properties of a quantum. You might try to listen to what Tom has to say; he's more an authority on physics than I.

I had meant by "magic" mostly physical phenomena that fascinate, but are not easily explained logically.

 

[elas]

Thanks for your reply, I admit that I was rather hoping that you new more than Tom and I agree that the sub-atomic wave particle nature is well established but, I also believe that it is possible to interpret in it in a deeper sense.
We analyze molecules, atoms and baryons by dividing them into their component parts; usually by finding the parts or (below the atomic level) indirect evidence of the existence of the parts, but in some cases (quarks for one example) by creating hypothetical parts and then looking for indirect evidence of the hypothetical parts existence.
I am suggesting that the ‘parts’ that make up a particle wave are force and anti-force. I have supported this proposal by showing that fundamental particles can be divided into three groups where all particles in the each group have the same total force spread over different volumes. I have also shown how this structure can determine the charge. This of course is hypothetical conjecture, but so also was the original concept of atoms and quarks and I cannot understand why such conjecture is dismissed out of hand by Tom. Fortunately not everyone has dismissed it in such an offhand manner and I now have to find another place to keep in touch with those willing to debate the merits or otherwise of my proposal.
But even Tom’s rejection has demonstrated two points that I shall need to enlarge on in the next revision. These are ‘what is the correct classification of QT’ and ‘what constitutes a theory’. A quick check on both these question (made because of Tom’s submission to this thread) shows that even among leading physicists, there is considerable differences of opinion on both questions; these need summarizing and including in the introduction so that readers can make up their own mind as to how my proposal measures up to each definition.
elas
PS Looking back on the Sakharof paper I quoted from ages ago, it occurs to me that a large part of the problem maybe my use of Newton's linear method in place of wave mechanics but for me, the name of the game is simplicity.
I will rewrite my proposal using only papers from Physics Review as references.

 

[quantumdude]

Thanks for your reply, I admit that I was rather hoping that you new more than Tom and I agree that the sub-atomic wave particle nature is well established but, I also believe that it is possible to interpret in it in a deeper sense.

Why were you hoping that? Because he is more amenable to your reasoning than I am?

What's the point of simply looking for people to agree with you?

We analyze molecules, atoms and baryons by dividing them into their component parts; usually by finding the parts or (below the atomic level) indirect evidence of the existence of the parts, but in some cases (quarks for one example) by creating hypothetical parts and then looking for indirect evidence of the hypothetical parts existence.

We don't create quarks. Nature took care of that for us. And the evidence is not indirect at all, it comes from scattering experiments. That is no more indirect than any other evidence we have from the subatomic world, where all evidence comes from either scattering or decay experiments.

I am suggesting that the ‘parts’ that make up a particle wave are force and anti-force.

You know that we aren't hosting overly speculative theories here any more. I am not going to remind you again.

I have supported this proposal by showing that fundamental particles can be divided into three groups where all particles in the each group have the same total force spread over different volumes. I have also shown how this structure can determine the charge.

You have not shown anything compelling reason to think that your idea is true.

This of course is hypothetical conjecture, but so also was the original concept of atoms and quarks and I cannot understand why such conjecture is dismissed out of hand by Tom.

I didn't say that I dismissed it, I said that you don't have a theory yet. The proposals of atoms and quarks were not pure conjecture, they were actually required to make sense of what was known at the time.

And as for dismissing things out of hand, I say you should look in the mirror. You have ignored just about everything I have ever said to you, dismissing it with irrelevant references from Hawking or the Encyclopedia Britannica. The fact is, I have spent more time looking at your website than you have spent looking at real physics. There's just not much of anything there to look at.

Fortunately not everyone has dismissed it in such an offhand manner and I now have to find another place to keep in touch with those willing to debate the merits or otherwise of my proposal.

If you have collaborators, then it should not be difficult for you to keep in touch with them via email. You might also try http://www.sciforums.com . They're well known to be left-of-center when it comes to conjecture.

 

[quantumdude]

PS Looking back on the Sakharof paper I quoted from ages ago, it occurs to me that a large part of the problem maybe my use of Newton's linear method in place of wave mechanics but for me, the name of the game is simplicity.

I think you are also having problems with the concept of "simplicity" in its scientific usage. I get the feeling that you think one scientific theory is "simpler" than another if its mathematical equations are easier to understand or if the objects in the theory have some (at least mentally) visual representation. That is not the case. One theory is simpler than another if it relies on fewer axioms. Typically, this sort of simplicity necessitates the use of more sophisticated concepts and mathematics. Since you are looking in exactly the other direction for simplicity, it's no wonder that it looks to you like physicists are going in the wrong direction.

The fact of the matter is that physicists are advancing in leaps and bounds, but it doesn't look that way to you because you are watching the car zoom away in your rear view mirror.

I will rewrite my proposal using only papers from Physics Review as references.

I think you mean Physical Review Letters.

 

[elas]

Tom

I think for the first time you have correctly sumed up my views in a dispassionate manner. We now clearly understand each other. I still think that I have given a clear explanation of the cause of mass, charge and energy conservation in a linear manner. As this is not yet possible using wave mechanics, I feel I am entitled to a hearing, you are entitled to dissagree.
I have decided where to go next and will only return to this subject on PF if I have more success elsewhere. That probably pleases you as much as it saddens me, but that's life,
thanks for your helpful comments, regards
elas

 

[russ_watters]

Being a little bit of a Hawking fan and someone who has read the book a number of times, I feel compelled to defend him here: elas has not provided a quote and admitted he's added his own interpretations. I'm don't feel compelled to accept that interpretation at face value. It'd surprise me greatly if Hawking said, or even implied, that QT is not science. Do you have a quote, elas (I'll attempt to find one tonight)?

Further, none of the quotes from other sources that elas did post support his position. He's implying his own spin and interpreting them differently than a scientist would.

 

[elas]

Have just recovered from several days of ISP problems. Will give considered reply as soon as possible. Have revised introduction to webpage; Table explanation will be revised next. Delighted to see debate continues.