Meeting 35

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DATE: Tuesday, April 27

TIME: 1 PM Princeton time (EST) / 8 PM Bucharest time (GMT+2)

PANEL: Leibniz on Laws and Spiritual Causation

SPEAKERS: J. Brian Pitts (University of Lincoln, University of Cambridge, University of South Carolina) & Andrew Chignell (Princeton University)


The Mind-Body Problem and Conservation Laws: An Outline in Light of the Growth of Physical Understanding

J. Brian Pitts

The success of science, especially physics, is often invoked as contrasting with the degeneration of world-views involving immaterial persons, whether purely spiritual or embodied.  A perennially popular question from the 17th century to the 21st is how, if at all, human minds can interact with bodies in light of physical conservation laws.  (Recently popular property dualism, if not epiphenomenalist, faces a similar question.)  This question has survived and helped to bring about a transition from a time in which educated opinion generally took interactionist mind-body dualism for granted to a time in which mind-body interactionism is widely rejected.  Leibniz was an early proponent of this objection in defense of a non-interactionist dualist view, pre-established harmony, a view popular in 18th century Germany for a time before the recovery of interactionism. 

This work aims to survey how this conservation law issue has been treated over the centuries, especially how it did (or did not) reflect relevant theoretical and experimental knowledge pertaining to conservation laws, as well as how well it worked as an argument (which, e.g., ought not to beg the question).  Leibniz’s Theodicy presents his objection as due to a growth in physical knowledge about conserved quantities since Descartes’s day: whereas Descartes accepted a conserved quantity of motion, Leibniz accepted a conservation of a directed vector quantity (momentum) as well as vis viva (an ancestor of energy), which was controversial.  In the 19th century, energy conservation was accepted.  In the later 19th century with the rise of electromagnetic waves, the handful of global conservation laws associated with point particles acting at a distance was replaced (in serious physics) with local conservation laws for each part of the world separately; in favorable circumstances the local laws can be integrated into a global law.  The local laws are (in those favorable circumstances) logically stronger, but they also permit milder failure modes.  In the 19th and 20th centuries, a connection between conserved quantities and symmetries of physical laws came to be understood, especially in connection with the principle of least action culminating in Noether’s work in 1918, which also included a converse:  a symmetry implies a conserved quantity and vice versa.  Also quantum mechanics appeared, with unclear implications.

Besides Leibniz, the issue engaged Euler, Kant, Maxwell, Helmholtz, Broad, and others, and continues to appear frequently in the contemporary philosophy of mind.  While the understanding available from physics has grown or in some cases changed, the philosophical treatment has remained largely static in roughly the physics of the 1860s among both friends and foes of interactionist dualism (with occasional exceptions).  General Relativity, now over a century old, also affects the discussion, albeit not in ways previously proposed.  This paper aims to survey the growth of knowledge on the conservation law mind-body issue. 

Leibniz on Miracles in the Best Possible World 

Andrew Chignell

Leibniz makes repeated efforts to stretch the frame of his rationalist-determinist picture to accommodate the traditional portrait of God as miraculously intervening in the natural world.  His goal is effectively to save the appearances of religious doctrine (or at least avoid direct conflict with biblical orthodoxy) while sticking to his metaphysical principles.  In this paper I consider Leibniz’s way of putting these two commitments together and argue that it is coherent: he can have his miracle doctrine and eat his deterministic cake too.  However, the combination results in a certain amount of epistemic inhospitableness, at least for finite minds.  This raises questions about whether it could really obtain in the best possible world. 

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