Abstract

Metaphysics has been rejected as nonsense by some philosophers (notably Hume and Ayer) because metaphysical systems cannot be tested empirically. This paper argues that these systems can still usefully be compared by using such criteria as: 1) Scope; 2) Not denying basic data; 3) Plausibility; 4) The minimum number of brute facts needed; 5) Engagement with and consistency with current science; 6) Lack of ‘promissory notes’; 7) Elegance and simplicity; 8) Clarity versus fudge. Berkeley’s Idealism and Physicalism (in both qualia realist and non-realist variants) are taken as examples and compared according to these criteria. Physicalism fares surprisingly poorly. It is all but inevitable that each person will possess a metaphysical system – and act upon it. If we fail to research alternatives then we are liable to assume a weak position implicitly (typically physicalism), and be reluctant to give it up.