The brain is wider than the sky, wrote Emily Dickinson, that other great philosopher-saint of selfhood. But, as Augustine observed, it is also wider than itself. We exceed our own boundaries; we are more and other than we know ourselves to be.
It feels mysterious, but the answer is that the mind can only contain a model of itself, like it contains models of other minds. The model of one's own mind is in greater detail, but cannot be a perfect copy. And even if it were a copy, this would imply little about such a model's predictive power, which depends on having the correct reductive abstraction. To have a reductive model of our own minds at all—which we do—means that the reality of our own minds is guaranteed to be mysterious to us. We can’t possibly know ourselves.
