Arrow Dynamics of time

A deep look at science shows that time and causality don’t work the way most of us intuitively think they do.  For example, some models of cosmology such as the one advocated by Sean Carroll in From Eternity to Here, claim that at some time in our past the (ancestor of our) universe was at minimum entropy.  At still further times from ours, its entropy was larger than that, and in its daughter universes on that other side of the minimum, entropy may grow as one goes further into (what we consider) the past.  So far, no big deal.  However, as Sean Carroll also argues, it appears that everything we experience as making time “flow” in one direction can be explained by the gradient of entropy.  As far as we know, it is physically possible that at some time intelligent beings exist(ed) in those daughter universes and perceive time to flow in the opposite direction. And their viewpoint is just as valid as ours.

Which direction the arrow of time points, depends on where and when you sit.  Arrow dynamics.  I will go a long way for a pun.

This – and other strange and wonderful discoveries of science – obviously have serious potential to change some philosophical thinking.  The area of philosophy I am most interested in, in this connection, is “the problem of free will and determinism”.  Most of the classic statements of this problem assume things about causality that find no place in modern science.  So here I list some resources that shed light on these issues.

Carl Hoefer points out that well known scientific deterministic theories are bidirectional in time: that is, they allow us to infer from the present or future to the past, just as easily as from past to future.

Huw Price and Ken Wharton explain how “retrocausal” QM theory can account for known violations of Bell’s Theorem.

Yakir Aharonov and Lev Vaidman discuss the Two State Vector Formalism (TSVF), an empirically equivalent formulation of standard QM that wears its time symmetry on its sleeve; and Aharonov et al apply TSVF to explain weak measurement experiments.  Guido Bacciagaluppi uses an alternative formalism to argue that a time-directed interpretation of probabilities, if adopted, should be both contingent and perspectival.

E. T. Jaynes partially explains the relationship between entropy and information.

Eric Lutz and Sergio Ciliberto discuss experiments on information storage and entropy changes.

Steven Savitt explores Being and Becoming in Modern Physics.

Larry Sklar says that “The great problem remains in trying to show that the entropic asymmetry is explanatorily adequate to account for all the other [time] asymmetries in the way that the gravitational asymmetry can account for the distinction of up and down.”

Craig Callender discusses the relationships between the thermodynamic (entropic) arrow of time, and other intuitively appealing arrows like epistemic (memory), mutability (our actions affect the future), and explanatory.

Mlodinow and Brun show that given plausible physical assumptions, recording and then reading a robust memory always proceeds in the direction of increasing entropy.  H. M. Doss places their work in a larger context.

In a tour de force, Jenann Ismael explains (0:55:00 – 1:38:00) why we see the past as fixed and the future as something we can bring about.  This one requires Microsoft Silverlight to view, which is a pain, but worth it.


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