Abstract

Aquinas's account of law as an ordering of reason for the common good of a community depends on the mereology that covered his theory of parthood relations, including the relations of parts to parts and parts to wholes. Aquinas argued that 'all who are included in a community stand in relation to that community as parts to a whole', and 'every individual person is compared to the whole community as part to whole'. Aquinas held that the perfection of wholes through the proper ordering of their parts does not entail the elimination of diversity, but in many cases requires diversity. Aquinas argued that there are two ways of ordering parts within a whole. Firstly, the parts are ordered with respect to one another, and secondly, the parts are ordered toward an end. The ordering of a whole's parts to one another is always for the sake of the ordering of the whole to its extrinsic end. Aquinas argued that the good toward which the law directs a community is called the 'common good' of that community. The common good or common end toward which members of a community are ordered can be the sort of end that the agents bring into existence through their own actions such as justice within a community, or the sort of end that can exist apart from the actions of the agents.