 By stating that “all sensations and vibrations are infinitely divisible,” Hartley is elaborating on a point made by George Berkeley, in his Essay Towards a New Theory of Vision ([1709] 1948), that a being born “blind” to bodily feeling and possessing only sight would have no concept of space and would be unable to perceive a geometrically ordered world. To such a being, sensations would be “infinitely”—i.e., arbitrarily—divisible. No stable, repeatable “ideas” could arise from them.