Abelard's philosophy is the first example in the Western tradition of the cast of mind that is now called nominalism. Although his view that universals are mere words (nomina) is typically thought to justify the label, Abelard's nominalism - or better, his irrealism - is in fact the hallmark of his metaphysics. He is an irrealist not only about universals, but also about propositions, events, times other than the present, natural kinds, relations, wholes, absolute space, hylomorphic composites, and the like. Instead, Abelard holds that the concrete individual, in all its richness and variety, is more than enough to populate the world. He preferred reductive, atomist, and material explanations when he could get them; he devoted a great deal of effort to pouring cold water on the metaphysical excesses of his predecessors and contemporaries. Yet unlike modern philosophers, Abelard did not conceive of metaphysics as a distinct branch of philosophy. Following Boethius, he distinguishes philosophy into three branches: logic, concerned with devising and assessing argumentation, an activity also known as dialectic; physics, concerned with speculation on the natures of things and their causes; and ethics, concerned with the upright way of life.