Cartesianism was incapable of an Æsthetic of imagination. The _Traité du beau_ by the eclectic Cartesian J. P. de Crousaz (1715), maintained the dependence of beauty not upon pleasure or feeling, matters about which there can be no difference of opinion, but upon that which can be _approved_ and therefore reduced to ideas. He enumerates five such ideas: variety, unity, regularity, order and proportion, observing, "_La variété tempérée par l'unité, la régularité, l'ordre et la proportion, ne sont pas assurément des chimères; elles ne sont pas du ressort de la fantaisie, ce n'est pas le caprice qui en décide_": for him, that is to say, they were real qualities of the beautiful founded in nature and truth. He discovered similar characteristics of the beautiful in the individual beauties of the sciences (geometry, algebra, astronomy, physics, history), of virtue, eloquence and religion, finding in each the qualities laid down above.[5] Another Cartesian, the Jesuit André (1742),[6] distinguished between an _essential_ beauty, independent of every institution, human and even divine; a _natural_ beauty, independent of the opinions of mankind; and, lastly, a beauty to a certain extent _arbitrary_ and of human invention: the first composed of regularity, order, proportion and symmetry (here André relied upon Plato and also as an afterthought brought in St. Augustine's definition): the second having its principal measure in the light which generates colours (as a good Cartesian, he took full advantage of Newton's discoveries): the third belonging to fashion and convention, but never at liberty to violate essential beauty. Each of these three forms of beauty was subdivided into _sensible_ beauty pertaining to bodies, and _intelligible_ beauty of soul. [Sidenote: _The English: Locke, Shaftesbury, Hutcheson and the Scottish School._]