If we could hear the endless material clatter of our bodies, the rustle of its elements one over another would hinder most efforts at communication. Much would be white noise, but some, and the most disturbing, would display the regularities of life, like the engine room hydraulics audible when lying in the bath with our ears beneath the waterline. It is fortunate that we so rarely catch even a fleeting half-heard fragment of this strain, which if not a dirge does suggest that, when all the variations have been worked through, the concert must come to an end.

The old, of course, are increasingly haunted by this music, while the young are happily insensitive to the physical and mechanical aspects of their perfectly functioning bodies and hear nothing but their own sweet voices. Consequently, the under thirties are the greatest enthusasts for the philosophy of spirit, which can only seem plausible when physical problems are fewest and the anaesthetic of dualism quite unnecessary. On the other hand, those who have the greatest need for a comforting division between mind and matter are denied an easy path into that view by the increasing racket of our functions, which throws before them the uncomfortable possibility that knocking pipes, creaking bone, and tearing muscle not only impinge on but constitute mental presence.