Augustin Louis Cauchy's Sept leçons de physique générale, delivered in Turin in 1833, give us his vision of the universe as a whole. The text, published in 1885, is of enormous interest. The author lays himself bare, contradictions and all. The mathematician was a man of science and broad learning, with an almost encyclopedic knowledge of the state of the art in his day. But he was also deeply religious, and therefore no heir to the Enlightenment. He declares as much in the very first lecture: "It is always in the name of the Enlightenment that doctrines are proclaimed which deal a death blow to intelligence or plunge it into the abyss of universal doubt." For Cauchy, a Christian above all, "we must unhesitatingly reject any hypothesis that contradicts revealed truths" (lecture 2).
The purpose of science ----------------------
What, then, is the purpose of science? The answer is simple: "the pursuit of truth" (lecture 1). But this pursuit is confined to the physical and mathematical sciences. Cauchy was convinced that only a tiny fraction of the truth is accessible to us here on earth. Human beings are certainly endowed with intelligence, but "everything revealed to them by their senses and intelligence is limited to a few of the properties with which beings have been endowed by the Creator" (lecture 2).
Taking two examples—the laws of gravity and the theory of light—he develops an experimental method that is strikingly modern given his convictions: "We must first study the facts, multiply our observations, seek to connect them through formulas, and thus identify the particular laws governing a certain class of phenomena." But "very often, the particular laws that physicists deduce from a large number of observations are not exact, but approximate". This remarkable method could not, however, encompass every field. Since "no facts are more indisputable than those on which the divinity of Christianity rests", Cauchy rejects, in particular, any notion of evolution—a hypothesis that Lamarck had already formulated several decades before Darwin's On the Origin of Species, published in 1859. For Cauchy, "the creation of human beings and animals cannot be the result of chance."