Francis Bacon’s (1561–1626) requirements for causal explanations were universally accepted as the basic principles of methodology in the new science. In the nineteenth century, the empiricist philosopher John Stuart Mill (1806–1873) restated them as the basis of scientific investigation in his time. Bacon’s aspirations for an association of scientists were eventually realized in the British Royal Society. Bacon’s methodological principles, combined with Kepler’s theory of elliptical orbits, were built on by Isaac Newton (1643–1727) for his culminating scientific system of the fundamental structure and operating laws of the universe. And Newton’s work was to hold at least until Albert Einstein’s (1879–1955) theories in the early twentieth century.