METAPHYSICS the underlying reality is the inWnity of animate monads; for Berkeley, it is the single all-comprehending God Hume on Causation If neither of these two philosophies is in the end credible, this is not due to any lack of ingenuity in their inventors Rather, the defects in each system can be traced back to a single root: the confused epistemology of ideas, which was bequeathed to rationalists by Descartes and to empiricists by Locke The philosopher in whose work we can see most fully the consequences of such an epistemology is David Hume His oYcial system, according to which everything whatever is a mere collection of ideas and impressions, is nothing less than absurd Nonetheless, Hume’s genius is such that despite the distortions and constraints which his system imposed upon him, he was able to make highly signiWcant contributions to philosophy Nowhere is this more evident than in his treatment of causality Prior to Hume, the following propositions about causes were very widely held by philosophers: Every contingent being must have a cause Cause and eVect must resemble each other Given a cause, its eVect must necessarily follow The Wrst two propositions were common ground between Aristotelian philosophers and their opponents Paradigm examples of Aristotelian eYcient causes were the generation of living beings and the operation of the four elements Every animal has parents, and parents and oVspring resemble each other: dog begets dog and cat begets cat, and in general like begets like Fire burns and water dampens: that is, a hot thing makes other things hot and a wet thing makes other things wet; once again, like causes like Early modern philosophers oVered other more subtle examples of causal relations, but they continued to subscribe to propositions (1) and (2) The third proposition was not quite such a simple matter Spinoza stated ‘Given a determinate cause, the eVect follows of necessity’ (E I,3), and Hobbes claimed that when all causal elements of a situation are present, ‘it cannot be understood but that the eVect is produced’ Aristotle, however, was not so determinist as Spinoza and Hobbes were, and he made a 204