The argument supposes the continuity of matter, that is to say, that the ultimate elements of matter are extended solids without interstices of vacuum. The dynamist theory on the other hand supposes that points, centres of attractive or repulsive force, are indissolubly bound up in primitive molecules, which molecules are extended, but not solidly continuous, there being vacuum between point and point of the multitudinous points which make up the molecule. In this theory, action takes place from each point, or centre of force, upon all points within the sphere of activity, accordingly to the law of the inverse square of the distance from the point, or centre of activity, attractive or repulsive. Thus every point is in immediate virtual contact with endless other points, but not in physical contact with any. Dynamism may be tenable or untenable: either way it is well worth the psychologist's while to consider what physical theory any argument of his presupposes, and what it excludes; and conversely, what physical theory, if established, would necessitate a modification of his argoment.

Of God and His Creatures: 2.56