Dear philosophers-physicists, As it turns out, I will not be able to make the first meeting of the philphys reading group on Tuesday. (I should have no problem attending future meetings.) But, since I read Wilson's article, I figured I would go ahead and give y'all some of my comments and questions, which may help foster discussion. (What I say here may give the impression that I was not impressed with the article; that impression would be correct.) 1. I found the discussion of Newton's Second Law in section 2 particularly disappointing. Given that Wilson in several places makes reference to Newton's own views on various matters, I find it incredible that he did not discuss Newton's original formulation of the Second Law, which is *quite* different in important conceptual and mathematical ways from the more familiar, Eulerian F=ma. Most importantly, and to speak somewhat anachronistically, Newton's formulation is an integral equation, relating integrated acceleration to what we would today call impulse. This is particularly important in the context of several questions Wilson does discuss, as it allows for the consistent treatment of the collision of perfectly inelastic point particles, which F=ma does not. There also should at least have been mention of the issues that depend on the class of mathematical functions one will accept as representations of possible forces. If one allows, e.g., distributional forces, then one can get discontinuities even in the time-evolution of the position of a particle, not just its velocity and acceleration. And yet, for many purposes, it seems difficult to do without distributional forces, at least for pragmatic reasons. 2. section 3, p. 6: Wilson is just wrong that Newton "had no notion that energy conservation holds." The last paragraph of the Scholium to the Laws in *Principia* very clearly states a conservation principle for energy, though, obviously, Newton does not describe it as such. 3. section 4, p. 8: I have no idea why Wilson says that, on the point-mass approach, "it becomes difficult to see how Newton's laws could be shown *false*; at best, they might prove an *inconvenient* series of approximations to utilize." Putting aside the fact that Wilson must have meant "at worst" and not "at best", he seems here to be doing nothing more than advertising his well known predilection for---prejudice in favor of---continuum readings of classical mechanics. He makes no real arguments in favor of the claim, and there seems to be an obvious counter-argument: if finer and finer approximations turn out worse and worse, then the most natural reaction would be to reject Newton's laws as false. 4. section 5, p. 9: I find his discussion of the supposed incompatibility of the point-mass approach and the existence of constraints to be, at best, baffling, and, at worst, deeply confused. His claim that the wire must be able to "see" the bead's velocity before the bead approaches a given point, in order to know the force needed to keep the bead on the wire as it passes that point, is just the deeply mistaken teleological reading of Newton's Second Law. The wire doesn't "know" or "see" anything. If the bead stays on the wire as it passes a given point with a given velocity, then we know the force the wire exerted on the bead at that point. That's all there is to say. And, in any event, even if one were to be able to make sense of what the hell Wilson is talking about here, *nothing* in the discussion indicates that it is in any way peculiar to the behavior of *point-masses*. If there is a real problem here, it arises for extended bodies as well. This is just, once again, Wilson's irrational prejudice against pointilliste readings of classical mechanics. (It's not that I'm a particular fan of pointilliste readings of classical mechanics---it's just that nothing Wilson says against them seems cogent or relevant.) 5. section 5, p. 11: "once the basic 'particles' of mechanics are granted any spatial extension at all, they are likely to lose their postulated rigidity"---Wilson seems to assume without argument or remark that this is a bad thing for the 'basic-particle' view. The only reason I can see for his thinking so is, again, his prejudice in favor of continuum-interpretations of classical mechanics. 6. section 5, p. 12: he says that, infinitesimal readings of F=ma, though common in textbooks, are a mistake, and that "the considered modern opinion" is that F=ma should apply only to extended parts of a continuous body. I have *no fucking idea* what he is talking about. First, I have read many works on classical mechanics, and I have never once seen that view expressed, by a physicist, by a mathematician, or by a philosopher---with the exception of Mark Wilson. I know he thinks highly of himself, but surely even he doesn't think that his saying so by itself automatically transforms a statement into "the considered modern opinion". Second, I don't even know what the view means. The only way I can begin to try to make sense of it is to interpret F and a in not obvious and highly unorthodox ways, and even then it seems highly likely that it just won't hold true most of the time, no matter what one does. 7. section 7, p. 14: The question that opens section 7 is silly. Nothing else. Why would any serious philosopher, historian or physicist think it is even a well posed question in the first place, much more one with an answer? E -- Erik Curiel Postdoctoral Fellow Munich Center for Mathematical Philosophy Lehrstuhl für Wissenschaftstheorie Fakultät für Philosophie, Wissenschaftstheorie und Religionswissenschaft Ludwig-Maximilians-Universität Ludwigstraße 31 80539 München, Deutschland http://strangebeautiful.com

Great. Actually I have the honor to be one of the editors of that extended manuscript. so it is NOT unpublished. It appeared in M. Stoeltzner, P. Weingartner (eds.), Formal Teleology and Causality in Physics, Paderborn: Mentis 2004. And I am really sorry that I have to be in Wuppertal for the final meeting in setting up a DFG Forschergruppe. Michael On 10/17/2014 10:17 AM, Fletcher, Samuel wrote:

Dear Colleagues,

Our next meeting will run from 14:15-16:00 on the date indicated. Erik Curiel will lead discussion on the first three sections of J. Butterfield's manuscript, "Between Laws and Models: Some Philosophical Morals of Lagrangian Mechanics." You can find the most up-to-date version of it on the Pitt PhilSci Archive (http://philsci-archive.pitt.edu/1937/) or on the arXiv (http://arxiv.org/abs/physics/0409030).

As a reminder, here is the schedule of meetings we (tentatively) agreed upon for the rest of the term: 28 Oct, 11 Nov, 25 Nov, 16 Dec, 13 Jan, 27 Jan.

For those who were not able to be present for the first meeting on Tuesday, I've attached a document with a list of possible topics we can cover. When we finish #4 (which is just the above manuscript by Butterfield), we'll vote on the next one. Also for those folks: please leave a bit of extra time to reach the seminar room, E341 in the main university building. The only entrance is from a special door accessible from the southern courtyard, which leads to a large stairwell. (The door is marked for E341.) One then reaches the room only after many flights of stairs. I'm sorry for the inconvenient location, but unfortunately it was the only room nearby available at our requested time.

Best wishes, ~Sam

Apologies for messing that up. You are right. Still a pity that I cannot come. Maybe I do the same as Erik did last time and send you some comments. Michael On 10/17/2014 2:42 PM, Samuel Fletcher wrote:

Hi Michael,

Aren't you thinking of "Some Aspects of Modality in Analytical Mechanics"? That is listed under topic #10, but it's not what we're reading for the next meeting.

Best, ~Sam

On Fri, Oct 17, 2014 at 2:28 PM, Michael Stoeltzner <stoeltzn@mailbox.sc.edu <mailto:stoeltzn@mailbox.sc.edu>> wrote:

Great. Actually I have the honor to be one of the editors of that extended manuscript. so it is NOT unpublished. It appeared in M. Stoeltzner, P. Weingartner (eds.), Formal Teleology and Causality in Physics, Paderborn: Mentis 2004. And I am really sorry that I have to be in Wuppertal for the final meeting in setting up a DFG Forschergruppe.

Michael

On 10/17/2014 10:17 AM, Fletcher, Samuel wrote:

Dear Colleagues,

Our next meeting will run from 14:15-16:00 on the date indicated. Erik Curiel will lead discussion on the first three sections of J. Butterfield's manuscript, "Between Laws and Models: Some Philosophical Morals of Lagrangian Mechanics." You can find the most up-to-date version of it on the Pitt PhilSci Archive (http://philsci-archive.pitt.edu/1937/) or on the arXiv (http://arxiv.org/abs/physics/0409030).

As a reminder, here is the schedule of meetings we (tentatively) agreed upon for the rest of the term: 28 Oct, 11 Nov, 25 Nov, 16 Dec, 13 Jan, 27 Jan.

For those who were not able to be present for the first meeting on Tuesday, I've attached a document with a list of possible topics we can cover. When we finish #4 (which is just the above manuscript by Butterfield), we'll vote on the next one. Also for those folks: please leave a bit of extra time to reach the seminar room, E341 in the main university building. The only entrance is from a special door accessible from the southern courtyard, which leads to a large stairwell. (The door is marked for E341.) One then reaches the room only after many flights of stairs. I'm sorry for the inconvenient location, but unfortunately it was the only room nearby available at our requested time.

Best wishes, ~Sam

Dear Colleagues, This is just a reminder that we'll be meeting tomorrow at the usual time. Over the weekend I fell ill and am still recovering, so there's a chance I won't be able to attend, in which case I'll appoint someone else to administer the vote on which topic to cover in the next meeting on 16 Dec. Best, ~Sam On 2014-11-12 15:26, Fletcher, Samuel wrote:

Dear Colleagues,

Our next meeting will run from 14:15-15:45 on the date indicated in E341 of the main university building. Mario Hubert will lead discussion on the topic of "Newtonian Forces," the reading for which will be the following:

1. John Bigelow, Brian Ellis and Robert Pargetter. "Forces," Philosophy of Science, Vol. 55, No. 4 (Dec., 1988), pp. 614-630. 2. Jessica Wilson. "Newtonian Forces," British Journal for the Philosophy of Science, Vol. 58, No. 2 (Jun., 2007), pp. 173-205.

These correspond to papers 3.1 and 3.3 on the "Possible Topics" handout, attached again to this email. Please contact me if you have trouble downloading copies of these articles. Also, be prepared again to vote on the topic for our following meeting (16 Dec.), keeping in mind that in January we will be discussing topic 7: "The Principle of Least Action and Dispositions".

Best wishes, ~Sam