Matias Slavov has a fascinating paper in the recent Hume Studies looking at what kind of mechanics, and in particular laws of dynamics, Hume assumes in some of his arguments ("Hume on the Laws of Dynamics: The Tacit Assumption of Mechanism", Hume Studies, Vol. 42, No. 1-2 (April/November 2016) pp. 113-116). He identifies five laws of dynamics that he thinks show up explicitly in Hume's discussions:
[I] A body at rest or in motion continues for ever in its present state, till put from it by some new cause.
[II] A body impelled takes as much motion from the impelling body as it acquires itself.
[III] The moment or force of any body in motion is in the compound ration or proportion of its solid contents and its velocity.
[IV] The equality of action and re-action
[V] Gravitation produces a motion from one thing to the other.
[I], of course, is the principle of inertia. [IV], which is Newton's Third Law, is mentioned only once (in the Dialogues) in order to argue against the possibility of mind affecting body; Slavov notes, however, that Hume seems to have a very different notion of force than Newton does. While Hume will occasionally talking about things that are interacting, he doesn't seem to countenance genuine interaction, in part because he takes causes and effects to be entirely separable in principle. For this to be the case, every interaction has to be something that can be broken down into two distinct happenings, each of which is attributed to one and only one thing. There is no genuinely shared action. As Slavov puts it:
Consider the following scenario explained by Newton's third law of motion. I press the table with my hand; the table presses my hand with equal and opposite force. What is the cause, and what is the effect in this scenario? Is my pressing of the table the cause, or the pressing coming from the table? In Newtonian dynamics forces are generated through interactions. Although Newton's second law is the causal law and his third law is rather a law of co-existence, it is still difficult to separate the supposed cause and supposed effect in dynamic interactions (for forces appear between mass points). But this is what Hume's separability principle requires. (pp.124-125)
(It is perhaps worth noting, to strengthen the point, that Newtonians often did interpret the Third Law as a causal law; William Whewell is in this tradition later when he uses the Third Law to argue that causation must be simultaneous. This last makes me wonder if it is not only the separability principle but also the principle that the cause must be temporally prior to the effect that makes a difference here. If one looks at Lady Mary Shepherd's causal theory, for instance, which is designed to handle interactions very well -- and in fact tends to treat all causation as interaction -- it's a theory that requires a fundamental commitment to simultaneity of causation. If cause and effect are separable, this means that interactions can be reduced to lower-order non-interactions; but one might think of them as hooking together somehow. If the cause must precede the effect in time, however, this means they are not only separable, they are actually separate. Simultaneity of causation is not enough to give you genuine interactions, but it seems to be a precondition for them.)
Slavov thus argues that Hume's view is in some sense mechanistic -- he has a mechanistic account of laws -- even though he rejects corpuscularianism, at least in the sense of being agnostic about most microstructural explanations, and so is not mechanistic in another sense. Mechanists in this latter sense treat laws as regularities of microstructure, whereas Hume treats laws as regularities of experiences that may or may not have much to do with any further microstructure. It also leads one to the conclusion that Hume, while in some sense Newtonian, is in a number of ways radically at odds with the Newtonian picture of the world. (Some things that Slavov says suggest that he thinks of Hume as lying somewhere between Cartesian physics and Newtonian physics.)
Various Links of Interest
* Aikin and Talisse have an interesting discussion of polarization and civic enmity (which they define as "the condition that prevails when democratic citizens lose the capacity to regard those with whom they disagree as entitled to an equal share of political power") at "3 Quarks Daily"
* Sandra Shapshay discusses the sublime at "Aeon"
* The Age of Metaphysical Revolution is a interesting project that looks at a letter from David Lewis each month as a way to look at his role in the transformation of analytic philosophy.
* Robert Paul Wolff on Alice Walker's The Color Purple
* Emily Thomas, Are spirits in space? Exploding spirits and absolute theories of space and time
* Thony Christie on Egnatio Danti: Cosmographer to a Grand Duke and a Pope
* Sebastian Musch, The Atomic Priesthood and Nuclear Waste Management - Religion, Sci-fi Literature and the End of our Civilization
* William Ewald, The Emergence of First-Order Logic, at the SEP
* Julien Dutant, The legend of the justified true belief analysis (PDF)
* Brian Kemple reviews Carrie Jenkins's What Love Is
* It looks like Newman is on his way toward canonization.
* John Brungardt on the possibility of a dispositional analysis for the principle of least action.
* Ricky Jay, often considered the best sleight-of-hand artist in the world and certainly its foremost historian, recently died. One of his personal assistants (not magic assistants) reflects on him.
* Rabbi Josh Yuter, "Love the Stranger" -- The Ger in Jewish Society
* Timothy Hsiao, The Moral Case for Corporal Punishment
* Megan Kimble, Austin's Fix for Homelessness: Tiny Houses, and Lots of Neighbors. It's a nice profile of Community First! Village, a charitable organization here in Central Texas. It's not a complete answer to homelessness, but it's a powerful one, because it recognizes that homelessness is not a lack of housing so much as it is a lack of community connection. I've occasionally had students who volunteered there for their service learning projects, and it seems to be a very solid idea. It's a sign of how a little ingenuity can go a long way in dealing with serious problems. Take someone off the urban street and put them in a village, with a little house and community gatherings and some ways to earn a small income, and sometimes they thrive.
* The collection of the Art Institute of Chicago, online.
Currently Reading
Jules Verne, The Lighthouse at the End of the World
Elaine Landry, ed., Categories for the Working Philosopher
Harry V. Jaffa, Thomism and Scholasticism
Gilles Emery, The Trinity
