In the more obscure scientific circles which I frequent, there is a legend circulating about a late, distinguished physicist who, in his declining years, persisted in wearing enormous padded boots much too large for him. He had developed, it seems, what to his fellows was a wholly irrational fear of falling through the interstices of that largely empty molecular space which common men in their folly speak of as the world. A stroll across his living room floor had become, for him, something as dizzily horrendous as the activities of a window washer on the Empire State building. Indeed, with equal reason, he could have passed an insubstantial hand through his own body.
The pulsing rivers of his blood, the awe-inspiring movement of his thoughts had become a vague cloud of electrons interspersed with the light-year distances that obtain between us and the furthest galaxies. This was the natural world which he had helped to create, and in which, at last, he found himself a lonely and imprisoned occupant. All around him the ignorant rushed on their way over the illusion of substantial floors, leaping, though they did not see it, from particle to particle over a bottomless abyss. There was even a question as to the reality of the particles that more them up. It did not, however, keep insubstantial newspapers from being sold nor insubstantial love from being made.