We perceive sights and sounds through eyes and ears, scents and taste through nose and tongue, texture and heat through fingertips. All that comes to us is filtered through the flesh. This is our phenomenal world.

Is it real? No – it’s sieved through neural mechanisms, as through the fabric of a veil.

Is it any more real to conceive sights and sounds as waves in fields and air, scents and taste as emitted molecules, touch as van der Waals forces, as science would do? No, these theories are creatures of the brain, aided by the left-brain integrator. Even our flesh and brain are imaginary pre- or con- cepts, not ultimately real.

We are forever cut off from reality – Popper’s World I – by an impenetrable wall. We no more know what the world is than we know who God is.

There are shadows on the cave wall that help us navigate in the real world, enough to ensure survival. Shadows are two-dimensional, while the world (we can suppose) is three-dimensional, or four if we take time into account. But not really. String theory postulates 10 dimensions, possibly 26, most of them “curled up”, whatever that means.

Why 10 or 26 rather than other numbers? (Phase space can have any number of dimensions, including infinity.) They follow from mathematical theories; again, how real? Angels are said to exist in more than four dimensions (space and time), how many we cannot know. To ask how many angels can dance on the head of a pin is not a nonsensical question. However, it is an unanwerable one.

Ich weiss dass wir nichts wissen konnen.
Das magt mir wohl das Herz verbrennen.
(Doktor Faustus. W. Goethe.)

Yet I am comfortable among the shadows, except when I think, often, with astonishment, “What IS this all ABOUT?”