Optimalism and logical possibility

Optimalism holds that, of metaphysical necessity, the best world is actualized.

There are two ways to understand “the best world”: (1) the best of all metaphysically possible worlds and (2) the best of all (narrowly) logically possible worlds.

If we understand it in sense (1), then the best world is the best out of a class of one, and hence it’s also the worst world in the same class. So on reading (1), optimalism=pessimalism.

So sense (2) seems to be a better choice. But here is an argument against (2). It seems to be an a posteriori truth that I am living life L_AP (the life in our world associated with the name “Alexander Pruss”) and that Napoleon is living life L_NB (the life in our world associated with the name “Napoleon Bonaparte”). There seems to be a narrowly logically possible world just like this one where I live L_NB and Napoleon lives L_AP. That world with me and Napoleon swapped is neither better nor worse than this one. Hence our world is not the best one. It is tied or incommensurable with a whole bunch of worlds where the identities of individuals are permuted.

Maybe my identity is logically tied to certain aspects of my life, though? Leibniz certainly thought so—he thought it was tied to all the aspects of my life. But this is a controversial view.

Energy conservation

On a Humean metaphysics, energy conservation implies a vast conspiracy in the arrangement of things throughout spacetime, somewhat like this:

1. Wherever there is a change in energy in one region there is a corresponding balancing change in another region.

In an Aristotelian causal powers metaphysics, energy conservation implies a fact like the following about every physical substance x:

2. Every causal power of x whose content includes an effect on the energy of one or more substances also includes a balancing reverse effect on x’s own energy.

That no physical substance simply has a power to affect the energy of another substance, without the content of that power having to include a balancing effect on one’s own energy, is deeply surprising. It is a conspiracy almost as surprising as (1).

These conspiracies strongly suggest that neither the Humean nor the Aristotelian metaphysics is the whole story about energy conservation. The conspiracies desperately call for explanation. I know of two putative explanations: an optimalist one (on which reality strives for value, and mathematically expressible patterns are a part of the value) and a theistic one. Both of these explanations, however, really do great violence to the spirit behind Humean metaphysics. But Aristotelian metaphysics with optimalism or theism explaining the conspiracy in (2) works just fine.

Of course, the problem can also be solved by a different metaphysics, one on which the behavior of objects is explained by pushy global laws. But it is harder to fit human freedom and agency into that metaphysics than into the Aristotelian one.