Abstract: For Berkeley, a spirit is a substance, understood in the substratum way that he attacked where material substances are in question. He opposed solipsism, as did Descartes and Locke, on the grounds that some of his ideas came to him unbidden and were therefore caused by external things. Holding (as Reid did) the puzzling view that only spirits can be causes, Berkeley concludes that there are spirits other than himself; his conclusion that there are other finite spirits is not well argued for. Berkeley is committed to holding that the only events a spirit can cause are the beginnings of ideas within itself; he has no basis for holding—and only thinly and intermittently does hold—that we cause the movements of our bodies.

Keywords: Berkeley, Descartes, Locke, solipsism, spirit, substance, substratum,