Contra Leon on Wave Function Realism

Felipe Leon thinks that wave-function realism should lead us to conclude that "ordinary perceptual experience is massively unreliable." He gives the following argument for this conclusion:

[It's] not at all clear how the ordinary three dimensions of our experience can be accounted for [given WFR]. In fact, some (e.g., Alyssa Ney) have argued that they probably can't, in which case there is non-trivial epistemic pressure to think the three dimensions of ordinary experience are, in an important sense, mirage-like.

Leon then argues that this leads to "troubling epistemic consequences for theism," because "if God exists, then God designed us in such a way as to ensure that our perceptual faculties reliably track the truth about the world." But if three-dimensional reality is illusory, then our perceptual faculties don't reliability track the truth, and as such, it is unlikely that God exists.

I think Leon is simply mistaken on this issue. To see why, take a look at this interview with philosopher of science Jill North (whom Leon also cites):

But ordinary 3-D space is not just an illusion, says North. “I think that 3-D space exists, and our talk about it is true. It’s just that this space is nonfundamental. Similarly, ordinary particles exist but are nonfundamental. They are more like tables and chairs: made up out of fundamental stuff, not themselves in the fundamental inventory.” 3-D space is a separate thing that is in some sense “made up out of” the higher-dimensional space, just as particles are ultimately “made up out of” the wave function.

Similarly, in a recent paper on wave-function realism and the place of 3D-space in a high-dimension world, Theodore Sider writes:

[High-dimensionalism] might suggest that rocks, trees, subatomic particles, and other three-dimensionalia are illusions, or intellectual mistakes, akin to phlogiston and phrenology, and should be purged from our cognitive lives. But high-dimensionalists cannot, and do not, take this hard line. In addition to being literally unbelievable, the view would be self-undermining. The empirical evidence for any scientific theory is three-dimensional, consisting of observations of pointer positions, computer readouts, and the like. If quantum mechanics implies that statements about pointer positions and the rest are all false, it does not imply any of our evidence, and thus it is incapable of empirical confirmation.

Accordingly, what high-dimensionalists say is not that three-dimensional matters are unreal, but merely that they are nonfundamental. High-dimensional fundamental reality “gives rise to” a nonfundamental three dimensional world. Thus high-dimensional quantum theories do, after all, imply facts about the three-dimensional evidence, and are therefore capable of confirmation.

Interestingly, Sider himself argues for a view on which high-dimensionalism is closer to what Leon supposes it to be (though he still accepts that our talk about 3D space is, in some sense, true). However, the point is that most defenders of higher-dimensionalism would reject the claim that 3D space is unreal.

As such, it seems that Leon is wrong to say that three-dimensional reality is "mirage-like." It may be nonfundamental, but it is not fictitious or unreal. This takes away most of the force from Leon's atheistic argument; after all, why should we expect God to give us accurate perception of fundamental reality? Isn't it enough that we perceive the level of reality on which we operate? One might as well say that our perceptions are misleading because we cannot see the individual atoms that make up the world around us! (NOTE: This is to say nothing of my own preferred view, on which reality is fundamentally an idea in the mind of God. What it would mean to "accurately perceive" this fact—and therefore. to have "reliable faculties" in Leon's preferred sense—is a mystery to me.)