Depth is of great psychological significance, and it is relevant that in schizophrenia, which simulates an overactive left-hemisphere state, there is, as Louis Sass has shown, a perspectival slippage, a loss of grip on the frame of reference.24 Attention ceases to be paid to, say, the scene pictured on the paper, and is transferred to the plane of the paper itself. There is a loss of precisely the transparency that operates when we understand something in the normal way.
