Thanks, Eric! Eric writes:
> I think of the two (principle of least action (PoLA) and natural selection > (NS)) in completely decoupled thoughts. > Yes, but can they both be understood as "selection" principles? with PoLA as a "selection principle" in this sense: The principle of least action is the basic variational principle of particle and continuum systems. In Hamilton's formulation, a true dynamical trajectory of a system between an initial and final configuration in a specified time is found by imagining all possible trajectories that the system could conceivably take, computing the action (a functional of the trajectory) for each of these trajectories, and *selecting* one that makes the action locally stationary (traditionally called "least"). True trajectories are those that have least action. Scholarpedia <http://www.scholarpedia.org/article/Principle_of_least_action> ( http://www.scholarpedia.org/article/Principle_of_least_action) For now, not wanting to get hung up on technical use of principle vs law or theory nor that NS has more mechanism/algorithm defined in its principle than PoLA. If you're cool with PoLA as a selection principle, I have a follow up email question. -Stephen On Tue, Nov 6, 2018 at 12:58 PM Eric Smith <desm...@santafe.edu> wrote: > Steve, hi, > > > As we've discussed over the last few years, The Action Principle (energy > * time) and least (stationary) action may provide a more fundamental > selection principle in biology than natural selection and could be a > mathematical formulation you're asking for. Many applied problems in > complexity like ant algorithms using dual pheromone fields, level-set > methods, and route search on a road network using simultaneous floodflill > from both origins and destinations might be considered least action path > selection. I make the claim on intuition - I expect Eric Smith would reject > or accept this based on more formal understanding. > > I don’t want to just drop this, but I don’t know how to respond to it > usefully. I think of the two (principle of least action (PoLA) and natural > selection (NS)) in completely decoupled thoughts. For me, PoLA in the > classical form is equivalent in content to dynamical equations, but because > it formulates them as an extremization principle it more readily exposes > consequences of symmetry. In quantum mechanics, I can find the same thing > as a stationary-path consequence of interference of phase advances over > many paths. In statistical mechanics I can find a “stochastic effective > action” that captures stationarity through a similar kind of interference, > but no longer among quantum phases, rather in some interaction of > distributions with the shadows of late-time questions we might ask about > them. (Sorry that formulation is so cryptic; for those who prefer that one > just show what one means by calculating, there is this: > https://arxiv.org/abs/1102.3938 > ) > > For me, NS comes up in response to a completely different collection of > questions (which may or may not be about the same phenomena). I think of > NS as being about whatever it is that makes time different from just > another dimension of space, so that there is always something falling apart > that can only be maintained by being passed through a filter. I would > prefer to use NS (or maybe, better, “Darwinian selection”) as a subset of > the previous general sentence, to refer to phenomena that are organized in > architectures of individuals and populations, as distinct from simple > kinetic phenomena in general. Of course one does not have to draw the > boundary there, but I find it a good way to use a new word to distinguish > individual/population-based phenomena from general kinetic organization, > for which we have other terms already. Also NS is about information in the > same sense (exactly) as Bayesian filtering is about information. Sometimes > effects of any of these, as they act in populations, can be expressed in > terms of actions, but I don’t think of the service that action gives in > displaying the nature of a calculation as being the same thing as NS does > in declaring what kinds of phenomena we are talking about. > > Sorry I could not offer better, or more likely I am not understanding > where the conversation is. > > Best, > > Eric > > > > > > > > > > > > > > On Sun, Oct 28, 2018 at 12:32 PM Eric Charles < > eric.phillip.char...@gmail.com> wrote: > > Bob Shaw has spend a good chunk of his career trying to do this at what > I would call a "lower level of analysis" even though that might not be the > right term. His "intentional dynamics" are about trying to use > dynamic-systems math to try to say what "intentionality" looks like in the > topology of an action. Thus, when I say "lower level" I mean that he is > interested in how one moves through the room to accomplish a goal, rather > than that one is doing a move-through-the-room option, which is what Nick > tends to focus on. That said, both approaches connect strongly, I believe, > with E.B. Holt's assertion that a central task of psychology is to > determine what aspects of the world our behavior is a function of, i.e., > the assertion that one is "trying to leave the room" is a description about > how one is acting, contextualized by an array of actions that would result > in an array of various outcomes. > > > > https://commons.trincoll.edu/robertshaw/ > > https://www.youtube.com/watch?v=om0HV5TQkXw > > > > Bob's work might really appeal to some on the list, which is why I have > linked both to his webpage and a talk from a few years ago. Differential > geometry, Feynman path integral, system dynamics, etc. If you want to skip > the less contextualized technical stuff and get to the big picture of his > effort, regarding the relation between the math he is using and psychology, > you could start at minute 50 and watch for about 10 minutes. > > > > For a touch more context: Bob was a crucial player in the second > generation of "ecological psychologists", those who kept James J. Gibson's > work alive after his death. Gibson's work is now extremely influential in > the emerging fields of "embodied cognition" (often called "enactivisim" in > European contexts). That said, most researchers in the field aren't > mathematically sophisticated enough to connect with Bob's work, and it is > technically challenging to implement in experiments, as such, few are > working on the project besides Bob, which is unfortunate. > > > > > > ----------- > > Eric P. Charles, Ph.D. > > Supervisory Survey Statistician > > U.S. Marine Corps > > > > > > On Sun, Oct 28, 2018 at 6:53 AM ∄ uǝʃƃ <geprope...@gmail.com> wrote: > > This description suffers from the same criticism I made before: you're > assuming a *strict* hierarchy, where the higher order can only operate over > whole components from the lower order. I.e. the gun's algorithm 1st > chooses the type/medium of target (ballistic, air, water), then uses that > type to select the specific tracking sub-algorithm. > > > > And while this is mostly how it's done in artificial systems, I suspect > biology does NOT use strict hierarchies. A higher order function can > operate over a mixture of operands, some complex wholes in that higher > order and some from the lower orders. E.g. if the gun's higher order > selection is based not only on the 3 types (ballistic, air, water), but > also on a lower order measure like *speed*, then it may well use he same > sub-algorithm for both air and water. So, it takes both high order > constructs and low order constructs as its operands. > > > > You see your assumption of a strict hierarchy peeking through when you > say sex is the only motive that is ESSENTIALLY social. What do you mean by > "essentially"? Couldn't we say that *all* the behavior of all the social > animals is, in part, social? ... including following others to the water > hole? So, these functions would be mixed ... do not obey a strict > hierarchy. > > > > On 10/27/18 11:32 PM, Nick Thompson wrote: > > > But the function that connects the two arrays will be different in the > two kinds of gun because a surface target is capable of different sorts of > motion from an aerial target. > > > [...] > > > So, the gun would display two levels of design, the lower level that > relates trajectory to firing and the higher level that relates the lower > level design to target type. > > > [...] > > > This conception of multiple hierarchical layers of design is a useful > way to describe many of the phenomena that ethologists and socio-biologists > are required to explain. … > > > > > > > > > > > > -- > > ∄ uǝʃƃ > > > > ============================================================ > > FRIAM Applied Complexity Group listserv > > Meets Fridays 9a-11:30 at cafe at St. John's College > > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > > FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove > > ============================================================ > > FRIAM Applied Complexity Group listserv > > Meets Fridays 9a-11:30 at cafe at St. John's College > > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > > FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove > > ============================================================ > > FRIAM Applied Complexity Group listserv > > Meets Fridays 9a-11:30 at cafe at St. John's College > > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > > FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove > > > ============================================================ > FRIAM Applied Complexity Group listserv > Meets Fridays 9a-11:30 at cafe at St. John's College > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove >
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