 The early modern causation debate revolved around a family of “nearly synonymous” key ideas, the most prominent of which were the ideas of power and necessary connection. For Hume, “there are no ideas, which occur in metaphysics, more obscure and uncertain”. He showcases the critical and constructive uses of his account of definition as he attempts “to fix … the precise meaning of these terms”, in order to “remove some part of that obscurity, which is so much complained of in this species of philosophy” (EHU 7.1.3/61–62).