 Influenced by the empiricism of Bacon and Locke, Bentham held that all knowledge is derived from sensation: the intellect has no material to work with apart from that obtained by the senses. In the second half of the 17th century, the Royal Society had emphasized the role of experiment and empiricist epistemology in the development of the natural sciences. Suitably impressed by the progress made in this department of knowledge, Bentham carried over into moral science the basic principle that people can only know, in any certain or scientific sense of that term, that which can be observed and verified. He argued that legal science ought to be built on the same immovable basis of sensation and experience as that of medicine, declaring “what the physician is to the natural body, the legislator is to the political: legislation is the art of medicine exercised upon a grand scale” (UC xxxii, 168).