Let the Vat-Brains Speak for Themselves

It's pretty standard to find pretty compelling the claim that for all one can tell one may be a vat-brain: not least, to say the least, because it's a version of Descartes' demon thought-experiment in the First Meditation. Here I refute that claim. Like Descartes I start with the idea that one has an undeniable grip on most of what one is thinking. To this I add the idea that knowing thinking as thinking is being able to engage in it. Then I argue that one can't engage in the (purported) thinking of a vat-brain (there are various specimens of vat-brain to be considered). The essential point is that one cannot make anything of what a vat-brain's intended ontology would be, and how the brain might conceive of it. So one cannot engage with any vat-brain's (purported) thinking. Yet one engages with one's own. So one isn't any of them. I'm not, anyway: you can speak for yourself.