Any imaginative hypothesis must be seminal, and Jonathan Harvey's is no exception. As he points out, a number of composers have been fascinated by the idea of harmonic structures radiating above and below a central axis in reflecting intervals. He says ‘from either side’ rather than ‘above and below’, and perhaps advisedly, for as soon as the concept of ‘below’ is permitted, so is that of gravity. The thesis depends on the removal of gravity in what is essentially a placeless, directionless space, without perceptible ups, downs, or sides. Swedenborg's rarified and not altogether realistic ideas come from a mysticism that is unclear about the nature of space. There are relative directions in space; it has dimensions; it is full of energy and radiation; in it gravity is inescapable. A man floating between earth and moon may not be aware of it, but he will drift in one direction or the other, according to which gravitational pull is the stronger. We can estimate at least roughly the distances between the galaxies, and their relative positions, their rates of movement away from each other if they do not belong to the same group. If the theory that in music the bass has moved to the middle refers to the apparent absence of an absolute bottom to the universe, it can be regarded as at least plausible, though without much basis in actual experience, and scarcely susceptible to proof. Where is this axis from which things radiate? It is not, presumably, a fixed and all too audible persistent internal pedal. No doubt it was there at the beginning, like the Big Bang, to be afterwards detected only by means of some residual musical radiation. It becomes an imaginary, or remembered, point.