  Second, his position is not only Naturalist but also Materialist. This Materialism is not of the rather crude kind that supposes that every reality is composed of a solid, crunchy substance, the stuff that makes up the atoms of Greek speculation. Any spatio-temporal reality, whether an ‘insubstantial’ property, such as a color, or something as abstract as a relation, such as farther-away-than, or faster-than, so long as it takes its place as a spatio-temporal element at home in the world of physics, is accepted as part of this one great spatio-temporal world. Williams’s Materialism is thus one which can accept whatever physical theory posits as the most plausible foundation for the natural sciences, provided that it specifies a world which develops according to natural law, without any teleological (final) causes.