 Many of the pre-Socratic philosophers in fact had a concept of substance rather like that above attributed to chemistry: that is, their emphasis was on criterion (vi) above. They thought, that is, that the being of the universe (hence they were pursuing substance in sense (i)) consisted in some kind or kinds of stuff. Thales, for example, thought that everything was essentially water, and Anaximenes that everything was a form of air. For Anaximander, the ‘stuff’ in question was indeterminate, so that it could transmute into the various determinate stuffs such as water, air earth and fire. By contrast, atomists such as Democritus took those determinate particular objects they called ‘atoms’ to be the substance of the universe. Atoms are objects in our ordinary sense, though they are not our ordinary objects: they are not dogs and cats or tables and chairs. They are the subjects of predication, but they do not change their intrinsic properties. Classical atoms are, therefore, strong instances of (i) and (ii), but somewhat deviant cases of (iii) and (v).