 McTaggart conducts metaphysics almost entirely from the armchair. In the first chapter of Some Dogmas of Religion, McTaggart characterizes metaphysics as the systematic study of the ultimate nature of reality. He then argues that the empirical sciences, such as physics, cannot replace metaphysical inquiry. The argument is roughly as follows. First, the claim that some empirical science such as physics provides knowledge of ultimate reality is not itself a claim of physics, but rather a metaphysical claim made about physics. And as such the evaluation of this claim goes beyond the province of physics. Second, McTaggart claims that metaphysical materialists, dualists, Berkeleyian idealists, and Hegelians all accept the same system of scientific propositions, whilst differing amongst themselves on the issue of how these propositions are to be interpreted. McTaggart concludes from this claim that there are metaphysical issues remaining even after we have settled on our best scientific theory.