Wednesday, October 4, 2023

Two priority monisms

According to priority monism, the cosmos is fundamental, and everything is a metaphysically dependent part. Priority monism is distinguished from existence monism according to which there exists only one thing (say, the cosmos).

Interestingly, one can split priority monism into a weaker and stronger version, where I restrict quantification over objects and facts to concrete objects and facts:

  1. Weak priority monism: The existence and intrinsic features of the cosmos fully ground the existence of everything else.

  2. Strong priority monism: The existence and intrinsic features of the cosmos fully ground all other facts.

Strong priority monism implies weak priority monism. As far as I can tell from Jonathan Schaffer’s discussion of heterogeneity, he subscribes to strong priority monism. But I think it is worth thinking about merely weak priority monism, because it avoids a certain problem that its strong cousin has.

On strong priority monism, given the asymmetry of grounding, no intrinsic feature of the cosmos can be even partly grounded in facts about an entity other than the cosmos. But suppose that Alice and Bob are fundamental particles located at the same position x, but with Bob having more mass than Alice. Then on strong priority monism, Alice’s and Bob’s masses are fully grounded in (the existence and intrinsic features of) the cosmos. But it is difficult to see how the cosmos can ground the facts that Alice is the one with less mass and Bob is the one with more mass without some kind of dependence on Alice and Bob. If Alice and Bob were at different locations, we could ground the difference in the fact that the cosmos is more massive in one location and less massive in the other. (But then we would have another problem: What grounds the fact that Alice is at the one location and Bob at the other, rather than vice versa?)

On merely weak priority monism, however, we can say that Alice and Bob’s existence is fully grounded in the cosmos, but facts about the mass distribution of the cosmos are grounded in the masses of the secondary beings like Alice and Bob. In other words, we have a two-way dependence in different respects. What makes the cosmos green here is that there is grass here, and the grass is green. What makes the grass exist is facts about the cosmos.

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