“One of the marks of our obliviousness, one of the countless signs that our thinking minds have grown estranged from the intelligence of our sensing bodies, is that today a great many people seem to believe that shadows are flat. If I am strolling along a street on a cloudless afternoon and I notice a shapeshifting patch of darkness accompanying me as I walk, splayed out on the road perpendicular to my upright self, its appendages stretching and shrinking with the swinging of my limbs, I instantly identify this horizontal swath as my shadow. As though a shadow was merely this flatness, this kinetic pancake, this creature of two dimensions whom one might peel off the street and drape over the nearest telephone wire. We identify our shadow, in other words, with that visible shape we see projected on the pavement or the whitewashed wall. Since what we glimpse there is a being without depth, we naturally assume that shadows themselves are basically flat—and if we are asked, by a curious child, about the life of shadows we are apt to reply that their lives exist only in two dimensions. Suppose,”