Potter (1977: 92) refines the argument. We say that A is nearer to D than to F because there are more intervening objects between A and F than there are between A and D. Suppose however that between D and F there is no chain of material objects. How is it that we can still say “A is nearer to D than to F”? Potter answers: “In order to provide the material to explain this comparative judgement we must postulate an intervening series of entities, and these must be spatial”. Note that this explains