tag:blogger.com,1999:blog-22973357.post5748014091413667856..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: What is a System?Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger38125tag:blogger.com,1999:blog-22973357.post-78185805730067496542016-03-07T07:06:02.841-05:002016-03-07T07:06:02.841-05:00Well here is a thought. (More related to social sy...Well here is a thought. (More related to social systems though.) <br />How about defining a system as a group of people, let say between 2 and 5, that when they are together changes their behaviour.<br />In this instance, the system is created only when it brings forward a change in the individuals behaviour. Denis Pageauhttps://www.blogger.com/profile/09341650161979710866noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-67813618213792024912008-08-04T08:44:00.000-04:002008-08-04T08:44:00.000-04:00Hi DenDen,That is an interesting suggestion, and o...Hi DenDen,<BR/><BR/>That is an interesting suggestion, and one that goes into the direction of some thoughts I had, but not regarding systems generally, but already rather complex systems. See, if the behavior of that group doesn't change, I'd still call it a system. Though possibly a rather dull one. Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-62476693653083676582008-08-02T08:37:00.000-04:002008-08-02T08:37:00.000-04:00Well here is a thought. (More related to social sy...Well here is a thought. (More related to social systems though.) <BR/>How about defining a system as a group of people, let say between 2 and 5, that when they are together changes their behaviour.<BR/>In this instance, the system is created only when it brings forward a change in the individuals behaviour.Denis Pageauhttps://www.blogger.com/profile/09341650161979710866noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-122408050999612902008-06-21T14:20:00.000-04:002008-06-21T14:20:00.000-04:00Hi Anonymous,This indeed captures very well what I...Hi Anonymous,<BR/><BR/>This indeed captures very well what I meant to express. Just that when I thought about it I came to the conclusion that the concept of a 'single constituent' does on a fundamental level not make sense. There are always virtual particle pairs and self-interactions that make even a single particle system one in which interactions are relevant. Maybe one should make that what Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73913393936341402562008-06-20T16:17:00.000-04:002008-06-20T16:17:00.000-04:00How's this:"System": the behavior of anything at a...How's this:<BR/><BR/>"System": the behavior of anything at all, regarded as a whole (however arbitrarily the boundaries are defined) that is composed of more than one interacting constituent entities that by themselves are either completely different (or subsystems) or, at the most fundamental (quantum) level, don't do squat unless some interaction occurs.<BR/><BR/>In other words, an interaction Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-8590945785154464022008-06-20T08:02:00.000-04:002008-06-20T08:02:00.000-04:00Hi Phil,Well, it just isn't a fundamental concept ...Hi Phil,<BR/><BR/>Well, it just isn't a fundamental concept in any regard, and yes, there is an ambiguity in it. That doesn't mean it's a useless concept. You can e.g. study the question: If I have a system with properties X, Y, Z then what will happen in situation A, B, C? The next question is then of course, is this an actual description of nature and under which circumstances? But that's a Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23520288281831434012008-06-20T07:51:00.000-04:002008-06-20T07:51:00.000-04:00Hi Anonymous,I have explained previously elsewhere...Hi Anonymous,<BR/><BR/>I have explained previously elsewhere that in fact I don't believe in freedom of choice, so I am probably a fatalist then. That however doesn't follow from what I've explained here. That you can make predictions within a certain accuracy about a system doesn't mean its entire behavior is predetermined. Models typically apply only in certain limits or on certain timescales Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53744642946200409742008-06-20T06:50:00.000-04:002008-06-20T06:50:00.000-04:00Hi Bee,Yes I was aware of the context that J.S. Be...Hi Bee,<BR/><BR/>Yes I was aware of the context that J.S. Bell was talking about a ‘system’ in. The point being is that the word as a concept itself wherever used is a contrivance to a large degree and as such far too subjective to be taken seriously as to be an element of anything that is to form the foundations of any fundamental concept one wishes to study and understand in terms of Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-67074671386915859952008-06-20T03:58:00.000-04:002008-06-20T03:58:00.000-04:00Bee said:Well, I'd have said a human being is a sy...Bee said:<BR/>Well, I'd have said a human being is a system. Why does this make me a fatalist? Best,<BR/><BR/>> Well, according to my characterization of system as something that behaves without freedom of choice, if you call man a system then you're endorsing the old fatalist thinking from XVIII century in a way, because then man would operate following a system, probably within the reach of Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-22235044630874329742008-06-20T00:42:00.000-04:002008-06-20T00:42:00.000-04:00Hi Bee,“Well, Dany, the fact that I'm a theoretica...Hi Bee,<BR/><BR/>“Well, Dany, the fact that I'm a theoretical physicist doesn't mean that theoretical physics is the only thing I'm interested in and write about.”<BR/><BR/>I referred to that:<BR/><BR/>“Asking myself how I and most of my colleagues seem to use the word, I would have said the system is that what is described by a model (see also: Models and Theories).”<BR/><BR/>You didn’t refer onAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5898503359736461032008-06-19T16:36:00.000-04:002008-06-19T16:36:00.000-04:00I'm not vexed. I was just looking for a definition...I'm not vexed. I was just looking for a definition of 'system' that works well with the way it is actually used, and I was wondering what people mean with 'complex systems' or 'political systems'. Sure, a system can have boundaries, I don't know what you're aiming at.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-37473862006562201052008-06-19T16:12:00.000-04:002008-06-19T16:12:00.000-04:00Anonymous tried, but then lapsed into some sad sol...Anonymous tried, but then lapsed into some sad solipsism. Freedom, indeed. Sheesh.<BR/><BR/>Phil's getting warm on what to address, here. Essentially, that part is 'context' and 'boundary conditions'.<BR/><BR/>However, the real question to ask, the question to ask you, Bee, and the question you might ask yourself is: what are you vexed over?<BR/><BR/>A potential following question is, what bellamyhttps://www.blogger.com/profile/12243108422389386105noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12435419018958698322008-06-19T14:06:00.000-04:002008-06-19T14:06:00.000-04:00Well, Dany, the fact that I'm a theoretical physic...Well, Dany, the fact that I'm a theoretical physicist doesn't mean that theoretical physics is the only thing I'm interested in and write about. I have never declared this a 'theoretical physics' blog, it just happened to be written by somebody working in this area. If you don't like that, nobody forces you to read what I write.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-34614853043960455372008-06-19T13:53:00.000-04:002008-06-19T13:53:00.000-04:00Hi Bee,“What I had in mind indeed had nothing to d...Hi Bee,<BR/><BR/>“What I had in mind indeed had nothing to do with physics whatsoever.”<BR/><BR/>“Events on the world lines of two theoretical physicists”<BR/><BR/>I have nothing to add.<BR/><BR/>Regards, Dany.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-68201952667620360082008-06-19T13:25:00.000-04:002008-06-19T13:25:00.000-04:00Hi Dany,I still don’t understand what the blogosph...Hi Dany,<BR/><BR/><I>I still don’t understand what the blogosphere is and what the purpose of discussions initiated by your posts is (to avoid misinterpretations I consider them and the comments very interesting and enjoy reading). However, you consistently DO NOT refer to the mainstream achievements of the theoretical physics (foundations of physics). </I><BR/><BR/>Well, this post just isn't Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35274902908956806462008-06-19T13:19:00.000-04:002008-06-19T13:19:00.000-04:00Hi Phil,Bell is talking about the QM aspect of a '...Hi Phil,<BR/><BR/>Bell is talking about the QM aspect of a 'system'. It is true that many of these concepts remain vague, esp. the question of what is the system and what is the environment. What I was aiming at here however wasn't QM, I was concerned with well, as I said, what do we mean with a political system, a social system, a biological system and so on, trying to figure out what 'General Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-68881358132752713102008-06-19T12:49:00.000-04:002008-06-19T12:49:00.000-04:00Hi Bee,I still don’t understand what the blogosphe...Hi Bee,<BR/><BR/>I still don’t understand what the blogosphere is and what the purpose of discussions initiated by your posts is (to avoid misinterpretations I consider them and the comments very interesting and enjoy reading). However, you consistently DO NOT refer to the mainstream achievements of the theoretical physics (foundations of physics). I think that at least the presentation of them Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-37501943815144350612008-06-19T12:42:00.000-04:002008-06-19T12:42:00.000-04:00Hi Fh,Thanks, this is interesting! I will have a l...Hi Fh,<BR/><BR/>Thanks, this is interesting! I will have a look at this.<BR/>Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-13402807003108938092008-06-19T12:41:00.000-04:002008-06-19T12:41:00.000-04:00Hi Anonymous,Well, I'd have said a human being is ...Hi Anonymous,<BR/><BR/>Well, I'd have said a human being is a system. Why does this make me a fatalist? Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-36382384257639122972008-06-19T10:22:00.000-04:002008-06-19T10:22:00.000-04:00Hi Bee, I think the expression in Ireland and the ...Hi Bee, I think the expression in Ireland and the UK is 'to buck the system', rehter more polite! <BR/>It has the connotation of achieving an outcome not quite intended by those who constructed the original system<BR/>(Example: Irish farmers squeezing subsidies out of the EU under all sorts of pretexts)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-57868529722596277392008-06-19T03:23:00.000-04:002008-06-19T03:23:00.000-04:00Surely the semantic bit that you have to consider,...Surely the semantic bit that you have to consider, my dear lost soul, to isolate a system is that when you're under one you have no freedom of choice, were you an elementary particle, a proteine in a chain of chemical reactions, an insect in its colony or a true believer in some sect. What's not a system? Man is not a system (even most animals aren't)or are you a fatalist?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56519348950323969812008-06-19T00:26:00.000-04:002008-06-19T00:26:00.000-04:00Hi Bee,You Said:"And then you go make models of th...Hi Bee,<BR/><BR/>You Said:"And then you go make models of these systems, find suitable variables, extract relevant parameters to try to understand the system and make predictions."<BR/><BR/>Simply as J.S. Bell would have reminded that the word ‘system’ is one of several words that should never be used in terms of a serious discussion:<BR/><BR/>“Why not look it up in a good book? But which good Phil Warnellhttps://www.blogger.com/profile/15671311338712852659noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35107788259953151402008-06-18T21:51:00.000-04:002008-06-18T21:51:00.000-04:00If you are familiar with some of contemporary Germ...If you are familiar with some of contemporary German philosophy/sociology you might find Luhmans theory of social systems interesting:<BR/><BR/>e.g.:<BR/><BR/>Georg Kneer / Armin Nassehi, Niklas Luhmanns Theorie sozialer Systeme, 4. Auflage, Utb, 2000, ISBN 3-8252-1751-5<BR/><BR/>http://de.wikipedia.org/wiki/Soziologische_Systemtheorie<BR/><BR/>http://de.wikipedia.org/wiki/Systemtheorie_(Luhmann)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-27163404611669607772008-06-18T20:16:00.000-04:002008-06-18T20:16:00.000-04:00Hi S1mplex,Well, the point that I tried to make is...Hi S1mplex,<BR/><BR/>Well, the point that I tried to make is that you can have some sort of set without any relation but this will only be an approximation. That might be an arbitrary good approximation, but it's always a matter of the range of parameters the model is good in. E.g. you could say that processes in your brain are in no relation to the star's constellation. But in fact there is someSabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-22445673518472640712008-06-18T16:31:00.000-04:002008-06-18T16:31:00.000-04:00Bee: The only example I can think of where one cou...Bee: <I>The only example I can think of where one could have, in Nature, a set of somethings without any relation (interaction) between the somethings is some sort of multiverse.</I><BR/><BR/>What about the "system" of primary and secondary properties? For example, what is the relation/interaction between a specific wavelength of light, and the color we perceive? Or, between a specific brain Anonymousnoreply@blogger.com