 Modern philosophers thought of themselves as scientific revolutionaries because they rejected Aristotle’s account of causation. Even so, they accepted his distinction between knowledge and belief, and regarded causal inference as an exercise of reason, which aimed at demonstrating the necessary connection between cause and effect. Malebranche (1638–1715), and others following Descartes (1596–1650), were optimistic about the possibility of demonstrative scientific knowledge, while those in the British experimental tradition were more pessimistic. Locke was sufficiently sceptical about what knowledge we can attain that he constructed one of the first accounts of probable inference to show that belief can meet standards of rationality that make experimental natural philosophy intellectually respectable.