Abstract

Both Thomas Aquinas and John Duns Scotus were committed to the view that effects with a contingent modality exist in the created world. This is to say that there are things that could have been otherwise. This chapter explores their respective accounts of the ontological reason for why there are effects with a contingent modality. Leibniz considered Aquinas’s and Scotus’s views on this issue, concluding that they were in fundamental disagreement about the ‘root of contingency.’ This chapter first makes a distinction between two different senses in which an object can have a contingent modality, one having to do with causation and the other with modes of existence. Then it applies this distinction to Aquinas’s and Scotus’s texts to show that their views on why there is contingency in creation are in fact quite similar.