After Kripke, pretty much everyone nowadays accepts moderate mental externalism: the content of our thoughts depends on the extra-mental world. On earth where the predominant colorless liquid with such-and-such properties, the word “water” refers to water (i.e., H2O), while on twin-earth where it is XYZ that has these properties, the word “water” refers to XYZ, and the thoughts that are expressed with sentences using “water” have a content involving water and XYZ, respectively, even if they are grounded in the same internal states of the brain and/or soul.
But there are stronger forms of mental externalism. First, we could have much more radical mental content externalism. Perhaps in one world the very same internal state means that there is water in the lake and in another world it means that the lake is dry but full of elephants. Second, we could have externalism about the subjective experience—the qualia—of mental activity. Thus, perhaps, depending on how extra-mental reality is, in one world one has the experience of seeing a red cube and in other that of smelling a daisy, despite having the same internal state in both worlds.
These stronger forms of mental externalism are rather counterintuitive and strange.
The point of this post, however, is that those of us who accept classical theism should take them much more seriously than we have tended to do. For on classical theism, God is simple and yet knows contingent extra-mental reality. This means that in different worlds God has different knowledge, while yet by simplicity remaining exactly internally the same. Hence we have an extremely strong mental content externism in the case of God: the very same state could mean that the universe consists of a lake with water and that it consists of a mountain covered by elephants. Moreover, if we add—as surely we should—that God’s knowledge is a conscious “vision” of reality, we also have to admit that externalism about subjective exerience is true of God.
Now, we cannot simply go from these externalisms being true of God to their being true of us. But I think we should take the externalisms in our case to be a very serious possibility.
A first attempt at exploring this kind of externalism in the case of subjective experience is here.
