Elle est dure et carrée : cela signifie encore qu’étant poussée, puis parcourue par la main, elle y suscitera deux espèces distinctes de sensations musculaires. […] The Law of Causation, the recognition of which is the main pillar of inductive science, is but the familiar truth, that invariability of succession is found by observation to obtain between every fact in nature and some other fact which has preceded it ; independently of all consideration respecting the ultimate mode of production of phenomena, and of every other question regarding the nature of “Things in themselves ”.