We argue that prevailing definitions of Berkeley’s idealism fail to rule out a nearby Spinozist rival view that we call ‘mind-body identity panpsychism.’ Since Berkeley certainly does not agree with Spinoza on this issue, we call for more care in defining Berkeley’s view. After we propose our own definition of Berkeley’s idealism, we survey two Berkeleyan strategies to block the mind-body identity panpsychist and establish his idealism. We argue that Berkeley should follow Leibniz and further develop his account of the (...) mind’s unity. Unity—not activity—is the best way for Berkeley to establish his view at the expense of his panpsychist competitors. (shrink)