Theories of universals and essences were strongly affected by the seventeenth-century mechanist movement, in large part because it replaced the scholastic-Aristotelian analysis of substance with the view that matter (and perhaps immaterial mind) is substance in its own right. By mid-century, the mediaeval problem of universals, concerned with the metaphysical composition of individual substances, disappeared from philosophical discourse. For Francis Suárez, an abstracted form remains particular. To have a general concept, intellect must compare a number of particular concepts and abstract from singulars. The movement away from Aristotelian science replaced various species of material things as paradigmatic subjects of necessary truths; mathematics and, perhaps, the laws of physics became the prime examples. To ground necessary truths, one could no longer appeal to essences that exist as ingredients in actual things. Many philosophers took the view that essences (qua archetypes) are eternal and directly dependent on some aspect or other of God.