  In a box of powder which is ground infinitely small and packed infinitely tightly, the slightest disturbance in one area will affect the most distant grains. If, however, the grains are relatively large and packed relatively loosely, one can imagine, for example, a circular motion of the grains in one area which does not affect even quite closely adjacent grains at all … Common notions of freewill and partial responsibility seem to involve a picture of the world rather like this…. The common notion assumes a ‘moderately’ loose packing in which there is elbow-room for a measure of free action, but in which we are sufficiently bound together by ‘necessity’ for us to have a measure of influence on one another and responsibility for one another.