If we follow Descartes, we cannot be certain of things “outside” the mind, which are otherwise “objectively present,” though the subjective content of the mind qua mind is minimally certain. Cogito ergo sum.
How is it that I know I am not psychotic, then, if the only content of my mind to speak of appears to me as objectively present? In other words, where is the minimal distance that separates truth from illusion, real from unreal, inside from outside?
Let’s make it clear by thinking of how people usually talk about The Matrix. They talk about being-in-the-Matrix as being different from being-not-in-the-Matrix, or rather, the kind of being of being-in-the-Matrix is different from the kind of being of being-not-in-the-Matrix. Where/what is the difference, but more difficultly where am I going when I traverse the fantasy of that difference?
UPDATE: Being-not-in-the-Matrix is, as far as I’m concerned, an absurd way to talk. Rather, for the sake of having a coherent sense of the world, we should talk about not-being-in-the-Matrix. There is a structural ambiguity here though: how are we to understand the difference between NOT being-in-the-Matrix and NOT-BEING (that is) in-the-Matrix? Is this difference simply a replay of the one I already considered. If the difference alludes you, think of at least two different ways to understand “he saw her with binoculars.” If that alludes you, you’re on the wrong blog.