Which of Our Basic Physical Assumptions Are Wrong? by Georgina Parry

Georgina

It is not a matter of arguing, but proposing different views, with substantiation and trying to establish what is correct. Which includes saying, not to you personally, 'hang on a minute, Einstein said this about SR, and that about something else'. Though this is really not what is going on most of the time anyway. That is enough to deal with. You may not believe it, given the number of posts I put out, but I only type with one finger. Its hard work, as it is, without dwelling on all the things that are correct/good.

Paul

Georgina

Wearing my Astronomer hat; Brilliant, clear, logical and consistent. From the Optics viewpoint; a sight for sore eyes, and as an Architect; excellently constructed, beautifully presented and nicely original. You must also be used to teaching some students who are maybe not the sharpest tools in the box, not only as it is among the more readable and comprehensible but because your patience in explaining the concepts is itself commendable.

I'm glad you persisted when you got tired, and really hope you get into the finals this year. I plan to read it again and maybe raise points, but 'first reads' are hard to keep up with when time just keeps going faster as space expands (doesn't it?!?)

Good score coming from me for sure. Best of luck.

Peter

Hi Peter,

thank you so much for prompt administration of the antidote.It was nice to read your highly complimentary comments. I am glad that even with just a quick look you can see some good points worth mentioning. I'm hoping that the simplicity of the presentation does not make readers, especially those unfamiliar with my explanations on the various FQXi blog threads, think that the essay can not contain anything of significance.There are a lot of ideas, solutions and suggestions packed into it.

The explanatory framework is still just the "bones" that give a coherent structure to physics. They can be fleshed out by looking at all sorts of different areas of research and seeing how they fit on those "bones".This was only briefly mentioned at the end as there was not room to elaborate. George Ellis' competition entry is talking about top down control of development and seems highly relevant. Also there can be development of a mathematical or symbolic representation and further understanding of the mathematical relationships of different parts of the framework itself.

Some areas of physics will not fit with the explanatory framework.It is likely that- because so many other aspects of physics will fit, and so many problems are overcome, those that can not fit are based upon physical assumptions that are wrong. The structure of the essay enables the essay question to be handled using compelling evidence and to be answered with conviction.

I have uploaded a high definition version of the diagram which is much easier to read into this discussion thread.

Georgina,

I didn't know Peter Jackson had responded to your essay, as I had not accessed your forum until just now.

I had just posted a comment to Peter's essay (topic 1330) where I quoted a statement from your essay. See Frank Makinson wrote on Jul. 20, 2012 @ 16:14 GMT

Hi Again Georgina,

I recently was reminded of a quotation by David Deutsch which made me think about your views and about your essay. Unless I'm mistaken, this is consistent with your views:

"Like an explosive awaiting a spark, unimaginably numerous environments in the universe are waiting out there, for aeons on end, doing nothing at all or blindly generating evidence and storing it up or pouring it out into space. Almost any of them would, if the right knowledge ever reached it, instantly burst into a radically different type of physical activity: intense knowledge-creation, displaying all the various kinds of complexity, universality and reach that are inherent in the laws of nature, and transforming that environment from what is typical today into what could become typical in the future. If we want to, we could be that spark." (From 'The Beginning of Infinity,' p. 75) A nice thought.

Cheers,

jcns

Dear Georgina

I very much like the overall way you have done this essay, using de Bono's ideas as a framework, and your overall analysis of image and reality (which is a key issue).Just one comment on that part: Tegmark is a very capable physicist but when he says "Evolution has endowed us with intuition only for those aspects of physics that had survival value for our distant ancestors, such as the parabolic trajectories of flying rocks" he is wrong - he's buying into the myth of evolutionarily determined folk physics modules, which don't exist. Actually nature has endowed us with the ability to learn from our experiences, which eventually enable us to anticipate how rocks will move - it's not innate.

The crux of your argument is your interesting diagram (thanks for the high-res version) which is in effect a model of how we create our models of reality. Where I part with you is your section "So which of our basic physical assumptions are wrong?' To my mind it goes a bit too far in emphasizing subjectivity rather than objective reality. They both exist - the issue is the relation between them. But then I am with you again in Diagram 2 (which will not surprise you).

One final comment: you say "Stephen Wolfram's cellular automata show that complexity can arise from certain inputs and certain sets of rules, reiterated upon the output" Actually the level of complexity that can so arise is very limited. Yes his patterns are fun: but they don't begin to compare with a single living cell. They are about as complex as you can get by bottom-up processes alone. Genuine complexity requires some kind of organising principle which is in essence equivalent to a top-down effect (I know it won't surprise you that I claim this).

Best wishes

George

Dear George,

thank you so much for reading my essay and taking the time to work out what the diagram 1. is showing. I would not myself word it as image and reality, but appreciate that you can see the important separation that is being made. I have, over a long time talking about these ideas on FQXi blog threads, worked out a precise way of consistently communicating the particular ideas. Object reality, exists independently of the process of observation and Image reality, that we experience as reality, is fabricated via the processes of observation.

The quote you picked out from Max Tegmark is, to my mind, above all amusing. I like his writing very much. It is taken out of the context of his essay but in both situations it is being used to say that we can not rely upon human intuition alone to answer the difficult problems of physics.Its not really IMHO a serious comment about how we come to have that intuition. I don't think it is saying that intuition is instinctive rather then learned but I see that it could be interpreted to mean that. Let me say then (combining Max Tegmark's and your arguments) that; evolution has endowed us with the ability to learn from the physics happening around us and thus to have intuition about what is happening or going to happen, shooting a hand out automatically to catch a ball in flight; but that doesn't help answer all of the difficult questions and problems of physics.

You said "To my mind it goes a bit too far in emphasizing subjectivity rather than objective reality. They both exist - the issue is the relation between them."

The explanatory framework I have set out (summarised in diagram 1.) is all about the correct relationship between them. Its not really objective and subjective as those terms are regularly used in science but unobservable, observer independent, reality and the observer's fabricated output reality from received sensory data. The explanatory framework, containing two different facets of reality and the data pool that bridges the two, is able to answer numerous long standing physics questions, overcome the paradoxes of relativity and prevent serious philosophical and theological problems.

In the section "So which of our basic physical assumptions are wrong" I have pointed out those basic assumptions that have to be wrong if the explanatory framework is correct, for example space-time is not independent external reality. There is sensory data distributed within the uni-temporal space but that is not space-time itself; it becomes space-time when the data is processed by the observer.

From what I have seen, and I have not read all of Stephen Wolfram's book about cellular automata, I agree with you that they don't have the complexity of a living cell but some are remarkably patterned. It is an interesting, different way to start modelling the material aspect of nature. I think complexity can be rapidly introduced into very simple models and that is one avenue that I am beginning to explore. In complex life forms there are many pattern generation controls operating together. Shape, surfaces and concentration gradients will all be able to affect the operation of the growth processes and a selection process will operate on the outputs culling defective patterns from the population.I mentioned natural selection as a larger scale pattern control mechanism in my essay. Above that, operating on every material thing at all scales is continual Object universal change and motion. (Missing from the space-time continuum model.)

I am really grateful for your feedback, and glad that there is some overlap in our viewpoints. Thank you.

Hi Georgina

It was nice to read your essay, I found it very clever and creative in the way how you exposed your points. I think you touch some important topics. Certainly I must confess that you touch so many topics which due to the lack of space it is impossible to treat them in more detail. I just would like to make some comments about the topics that you touch.

You have listed many of the inconsistencies found in physics by making a comparison between theory and the "observed" reality. It seems to me that you have noticed that physicists some times make non-sense assumptions. If you have read my essay I am sure that you have understood the why. Some times it is very difficult to model in mathematical terms the reality and theorists must resort to weird assumptions and oversimplifications of observations or data.

On the other hand, I would like to make clear something about the following. I think that there is some misconception with respect to QM. For instance

You say: Einstein's relativity is completely deterministic but QM relies upon probabilities and so is

non deterministic.

Relativity is certainly deterministic, and it is deterministic because it deals with macroscopic systems which are not considerably affected by the process of measurement. But however, QM has two components. If you take a look at the Schrodinger equation you will realize that the equation has a deterministic character. While doing the calculations of a particular system one assumes that reality is deterministic. The harmonic oscillator, the hydrogen atom etc. are treated formally as deterministic problems. The probabilistic part arises from the measurement problem, the uncertainty principle etc.. So one can consider that QM assumes a deterministic reality but however the measurement problem makes this deterministic reality non-deterministic because the measurement affects the system under study. Recall what I mentioned in my essay with respect to this assumption. If the measurements on macroscopic scale affected considerably the system under study relativity theory would most probably become non deterministic. I hope you have gotten my point. What I said is highly connect it with this:

You say: Classical physics can't explain; the probabilistic physiological effect of radiation, the

photoelectric effect, line spectra, black body radiation, wave properties of the electron. QM

can.

You also said that: There seems to be an arrow of time that is inexplicable by Einstein's relativity or QM

I think that the cause of this lack of explanation has to do precisely with some of the false assumptions that I point out in my essay. If you consider thermodynamics, in particular the second law teaches us that the entropy of a system always increases, this means that no process is reversible. One can interpret this as if no event is repeatable, that is, that a given event cannot repeat again in exactly the same way. This suggest that there is an arrow of time pointing in just one direction. Therefore, relativity and QM cannot explain this asymmetry because they were designed to describe only reversible processes. The asymmetry arises due to the construction of the equations that allows to repeat the events in any direction of time. Consider for instance, Newton equation, F=am=md^2x/dt^2, if you change t for -t you will get again the same equation. This same thing happens with Einsteins equations and the Schodinger equation. What I want to make clear is that these 3 equations again are describing an ideal universe that in reality does not exists, actually they describe a very simplify universe but these equations are useful to make the practical calculations required for technological applications.

Finally, I would like to say that to a certain degree Max Tegmark is right. His task is to try to find the correct mathematical structures to get rid of the baggage. He assumes that for every physical element of reality there most be a mathematical one. I think that this may be possible for quantitative explanations (this is why mathematics is used in physics) but not for qualitative matters in which the baggage is fundamental to understand our ideas.

I wish good luck in the contest

Israel

Dear Israel,

thank you for reading my essay and for your explanations. I'm glad you liked the form of presentation. I hoped to write something with much greater clarity and ease of reading than last years FQXi essay, and that other essay I sent to you. I think I have improved my writing by reading "The craft of scientific writing" by Michael alley, listening to your advice and looking at the examples of well written papers. Concentrating especially on setting out the points clearly and using simple language, grammar and sentence structure.

It was not my intention to deal with all of the points touched upon, but to answer the essay question using my own explanatory framework, (which you have seen before) as the means to accomplish that task. There is also a high resolution version of the diagram in this discussion thread. To me that framework is the most important thing in the essay. I was limited, as we all have been, by the permitted character count and so could not develop ideas or discuss them more comprehensively. Without a character limit I could easily have written an essay twice as long. However then it would then have become rambling and tedious rather than concise and enjoyable. It benefits from being less.

I've taken Brendan Foster's advice, that he gave on the blog threads, which was to the effect -if including own work to show how it is relevant and to show development. I also cited your essay, (that you sent me to look at), after my essay with other useful background material because it contains a large number of important "foundational" ideas that are clearly explained.

You make an interesting point about the difference between quantitative and qualitative matters. That other essay of mine, ( you asked me to send to you) was saying that philosophy should not be divorced from science. That it is important to find the correct relationship of ideas not just matters of fact. However I think that having the correct relationship of ideas and the matters of fact they can then be expressed in a formal symbolic way, if not a mathematical way. More so than diagram 1. Though some qualitative products of the human sensory system such as -subjective experience- of colours, sensations and emotions might not be adequately expressed through formal symbolism. These are probably not within the scope of physics. Such matters may be better left to poets, lyricists and artists whose work is able to stimulate the imagination and recreate the sensations and emotions they have expressed through their language or visual art.

Hi Georgina

No problem, I think that this contest is good for all of us in the sense that one can interchange ideas, improve the quality of our works and stimulate our imagination, there is no doubt about it. This contest also makes you realize what your weak and strong points are. Indeed, I noticed that you cited my work, thanks for that I appreciate it.

I agree with you that philosophy should not be divorce from science, in particular physics. But for physicists mathematical matters are more important due to the quantitative character of this science. As I mention in my essay, what matters for science are quantitative predictions because this leads to technological applications. And this is related to the fact of how scientists work. If you would like to understand in more detail this I suggest you should read two important books from the philosophy of science: (1) The structure of scientific revolutions, the author is Thomas Kuhn and (2) Against Method, Paul Feyerabend. The first book focuses on how the changes of thought and paradigms take place in science. The second one deals with the fact that science does not follows rules. Feyerabend argues that for science to make progress, scientists have to be anarchic. A theory gains his popularity not only because it is plausible but also because it is highly promoted.

Good luck in the contest

Israel

my dear Georgina, I saw that you answered already to Bobby Gilbertson on the thread of my essay of last year. I am awaiting now the acceptance of my new essay "THE CONSCIOUSNESS CONNECTION" which I hope will be soon, I am sure that is a lot to discuss together, both our perceptions of "reality" are touching each other but also flying far away. Wilhelmus

Dear Georgina,

I posted new paper in vixra.org, it is http://vixra.org/abs/1208.0018

in my new paper I discuss my MSRT in more comprehensive sense. How can we understand Lorentz transformation equations by a different way from Einstein SR. How my new interpretation is agreed with quantum field theory, and then how can we solving the contradiction between quantum field theory and GR by the modified General relativity according to my MSRT. In my paper I answered the question if Light bending by gravity or refracted? this is the lost key in order to unifying between quantum gravity and relativity.

(As I have mentioned in my message to Daniel Wagner Fonteles Alves on his essay thread "Absolute or Relative Motion... or Something Else?") This paper ALGEBRAS, QUANTUM THEORY AND PRE-SPACE F. A. M. FRESCURA and B. J. HILEY Department of Physics, Birkbeck College, London WC1E 7HX UK (Received In February, 22, 1984) like my own framework, argues for different facets of reality.Called in that paper implicate and explicate order not Object and Image realities. The explicate order is emergent. I think the most important passage starts-

Quote:"For Bohr, this was an indication that the principle of complementarity, a principle that he had previously known to appear extensively in other intellectual disciplines but which did not appear in classical physics, should be adopted as a universal principle. The Cartesian view was thus limited and had to be replaced by a very different outlook which was to be justified by the principle of complementarity in which complementary views, which at a classical level are contradictory, enter the description of nature in a necessary and essential way." End Quote

I agree, as what something -is- and -does- is ('spread over') all scales that might be considered not just at the singular scale of one observer (or class of observers of same type) It is also the parent/source of the data that has the potential to be everything that it might be observed to be, not just one viewpoint.

THAT is what needs to be considered to get the probability of a particular outcome or manifestation in Image reality.The something in Object reality is everything it might become known to be, not just what it is seen to be in one detection.

That paper ALGEBRAS, QUANTUM THEORY AND PRE-SPACE F. A. M. FRESCURA and B. J. HILEY Department of Physics, Birkbeck College, London WC1E 7HX UK (Received In February, 22, 1984),is all very interesting, further on it says-

Quote "What then becomes a fundamental form of description is the relation between the implicate and the explicate orders. In this view, space-time itself must be part of an explicate order. When this order is in its implicate form, it is called pre-space (Bohm and Hi1ey [6]). In this view, the space-time manifold is not a priori given. Rather it is to be abstracted from a deeper pre-space.

In this pre-space, the notion of locality is not primary but is a relationship in pre-space which, in an appropriate explicate order, becomes a local order in the explicate space-time. Exactly what links this explicate order with our classical view of space-time is not complete1y understood yet....."End Quote (the spelling "complete1y" reproduced from the original)

The reference [6]is to this 6. Bohm D. and Hiley B., Generalisation of the Twistor to Clifford Algebras as a Basis for Geometry, Revista Brasileira de Physica, Volume Especial, Os 70 anos de Mario Schonberg, 1-26, 1984. These references are also very relevant 4. Bohm D., Wholeness and the Implicate Order (Routledge and Kegan Paul, London, 1980).5. Bohr N., Atomic Physics and Human Knowledge (Science Editions New York, 1961).

There is a parallel between the concept being described and what the explanatory framework I have set out is. Object reality is implicate, Image reality is explicate and the bridge is the potential sensory data within the (object reality)environment that allows fabrication of the explicate image reality by the observer. That is also what I am referring to in the essay when I indicate there may be some overlap with Roger Penroses' quaternion description of the light cone and Joy Christian's recent work.I think they relate to a specific aspect of reality, the bridge between implicate and explicate, not reality in toto.

Hi again Georgina,

I awoke earlier than usual this morning (my best time of day to attempt what passes here as clear thinking) and felt a burning desire to read something logical, so I read your essay again. The term "tour de force" is an apt description of your essay. And thus far it has stood the test of time.

Of course, all these words of praise should not be taken to mean that I'm in total lockstep with each and every one of your specific conclusions (I must admit to being agnostic with regard to your conclusions about gravity and space-time curvature, for example. I fear that gravity has a much firmer hold on me than I have on it), but the overall impression one is left with after reading your essay is one of having read the work of a clear thinker.

You wrote, "There is no reason to assume that the Object universe does not have an eternal history. It is always only the newest iteration of itself but containing data generated within earlier iterations." I like that. It's my own view, fwiw, that the universe has one, and only one, real history, albeit one which necessarily will be perceived differently by different observers. James Gleick, in his fascinating book 'The Information,' commented that "the universe computes its own destiny."

While I obviously can't speak for anyone else, I find myself living in an evolving three-dimensional universe. Space-time, for me, is a potentially useful but also potentially misleading mathematical abstraction having no ontological reality. It arises partly as a consequence of a faulty view regarding the fundamental purpose of clocks, which, in turn, leads to a faulty view regarding the fundamental nature of time. But as you well know, you really don't want to get me started on all that.

Always nice to drop by! Thanks again for the refreshing essay.

Cheers,

jcns

Hi J.C.N Smith,

I am so glad you did pop by because it has been very quiet here. I will happily discuss why those particular conclusions are a necessary consequence of the explanatory framework I am using. If you look at the diagram 1., (there is a high resolution version in this thread), you can see two different facets of reality shown on different levels. One which is observer independent and the other which is fabricated by the observer from received sensory data. One is source of the data, the other is output from data processing, and the data is the bridge between them.

I do not know if the previous post I left here is useful to you.That paper ALGEBRAS, QUANTUM THEORY AND PRE-SPACE F. A. M. FRESCURA and B. J. HILEY Department of Physics, Birkbeck College, London WC1E 7HX UK (Received In February, 22, 1984) Quote "What then becomes a fundamental form of description is the relation between the implicate and the explicate orders. In this view, space-time itself must be part of an explicate order. When this order is in its implicate form, it is called pre-space (Bohm and Hi1ey [6]). In this view, the space-time manifold is not a priori given. Rather it is to be abstracted from a deeper pre-space."

That is precisely in line with the framework I have developed independently. My Source or Object reality is within what Bohm is calling pre-space and the output reality is a space-time manifestation, a representation of what exists formed from the data received, equivalent to the explicate order.

Since the space time is a fabrication from data, like a virtual reality simulation, it can not be curvature of space-time causing gravity. It is I suggest distortion of the environment of the unobserved Object reality (pre-space).The distortion is due to the motion of the Earth or other body under consideration, not merely its presence. The distortion alters the paths of light rays affecting when the data will be received and subsequently fabricated into the experienced reality. Which gives the emergent effect, the appearance of apparent curved space-time.

The motion responsible for gravity is also a likely candidate for a number of other phenomena, the sequential iteration or continual change giving passage of time at the foundational 'pre-space' level; the problematic red shift (moving away from the origin source of the sensory data detected); the matter antimatter inequality, matter going easily with the continual flow of most Object universal paths minimising potential energy, antimatter attempting to going against it.

For everyday purposes of safe locomotion and navigation, thinking of the observed reality as 3 dimensional is sufficient. However on further consideration it is clear that it takes more time (more arrangements or iterations) for light emitted from very distant objects to reach the observer than near ones. It is the data that is formed into the observed reality not the source objects. The data transmission and processing delay leads to the emergent effect of space-time.Remember we are seeing the output manifestations and not the actualised source objects.

It is really nice to hear that you still like my essay and thought it worth another read. Thank you very much. There are now very many good ones in the competition and no doubt yet more to come. Georgina

Hi Georgina,

"For everyday purposes of safe locomotion and navigation, thinking of the observed reality as 3 dimensional is sufficient. However on further consideration it is clear that it takes more time (more arrangements or iterations) for light emitted from very distant objects to reach the observer than near ones. It is the data that is formed into the observed reality not the source objects. The data transmission and processing delay leads to the emergent effect of space-time.Remember we are seeing the output manifestations and not the actualised source objects."

Yes, of course. You're preaching to the choir. We're in total agreement on this. When I said I find myself living in an evolving three-dimensional universe, this is of course exactly what I'm talking about. In spite of all this, however, it's still an evolving three-dimensional universe. Let's not lose sight of that fundamental fact either.

Unfortunately, the configuration of this evolving three-dimensional universe is intrinsically unknowable to us except through sensory data as discussed in your essay. The best we can ever hope for, therefore, is our accustomed ration of out-of-date, best approximations of objective reality. But we manage to muddle through amazingly well in spite of this handicap. We're accustomed to this condition, having never experienced anything other. Had we not learned to compensate and make the best of a less than ideal situation, we'd not be here.

Cheers,

jcns

Hi J.C. N. Smith ,

I'm sorry for telling you what you know well yourself. I am so accustomed to repeating it. (John might say banging my head against the wall.)

Whether it is best thought of as a 3 dimensional universe at the foundational level (ie. in Object reality or pre-space) is debatable. It can be thought of as such as it matches our understanding of reality from experience. However, many different observers equidistant from an object could simultaneously look at it and see it differently. Each is receiving different data emitted from the source object and imposing their own 3 dimensional structure onto the manifestation. The source object has to be the parent of all of the manifestaions not any one.

So is it a 3 dimensional source object in a single 3 dimensional space? How are the dimensions to be oriented? I don't think they can be put in one absolute orientation.John has argued for a long time that there must be infinitely many dimensions. I just think that perhaps the 3 dimensional description is inadequate and it may be better to think of objects spread out in all directions from their centres of gravity.

You make a good point about compensation for the imperfect knowledge we obtain via our senses. I think it was one of the FQXi conference lectures that touched on the way in which the human brain compensates for the mismatch of visual and auditory inputs. Might have been David Eagleman's but I will have to check that.

Yes it was "David Eagleman on Choice" Its on You tube and on this FQXi site somewhere.

Hi Georgina,

"So is it a 3 dimensional source object in a single 3 dimensional space? How are the dimensions to be oriented?"

From the perspective of my incredibly simplistic view of the universe, this question is too complicated. Here's my simple view, fwiw:

1.) The universe is comprised of a whole big bunch of "stuff" bumping around "out there" (i.e., apart from the bits and pieces which are myself, myself being just an infinitesimally tiny portion of the totality of the stuff).

2.) There is some real, evolving relationship among all the various bits and pieces (and yes, EM data are a part of all the stuff).

3.) The instantaneous nature of these evolving relationships is intrinsically unknowable to me, *not* because the instantaneous relationships do not exist, but solely because of limitations imposed on me by the nature of sensory data for which I'm equipped to be conscious/aware).

4.) The relationships among all the various bits and pieces appear *not* to evolve randomly; rather, this evolution appears to be governed by rules with we strive to understand and which we refer to as the laws of physics.

5.) Regardless of whether this evolution progresses in quantum steps or continuously (still to be determined), this evolution constitutes the "history" of the universe.

6.) Empirical observations available to me lead me to conclude that the universe has one, and only one, real history.

7.) Due solely to limitations imposed by sensory data (as discussed in point 3 above), every observer of the universe will *perceive* its evolution differently.

8.) Observers such as human beings have developed the ability to think about and to interpret their empirical observations and to communicate these interpretations with one another in a way which allows them to form, incrementally, increasingly better understandings of the universe in which they find themselves.

This has been an incredibly complicated way to convey to you what is an incredibly simple view of the universe. But sometimes it's useful to spell things out carefully; we may take for granted that these things are "obvious," but they may not be obvious to others, who may think that what is obvious to them is contradictory to what is obvious to us. The only way to get to the root of it is to use our words carefully.

"The way to converge with each other is to converge upon the truth." (David Deutsch, 'The Beginning of Infinity')

I'll close by sharing another favorite quote:

"What guarantees the objectivity of the world in which we live is that this world is common to us with other thinking beings. Through the communications that we have with other men, we receive from them ready-made reasonings; we know that these reasonings do not come from us and at the same time we recognize in them the work of reasonable beings like ourselves. And as these reasonings appear to fit the world of our sensations, we think we may infer that these reasonable beings have seen the same thing as we; thus it is we know we have not been dreaming." (Henri Poincare, 'The Value of Science,' published in 1913.)

Cheers,

jcns