Ariel Melamedoff

In her 1824 monograph An Essay upon the Relation of Cause and Effect, Lady Mary Shepherd presents a rich theory of causation that radically departs from the standard mechanistic causal model of the Early Modern period. I argue for interpreting Shepherd’s causal relation as the relation of metaphysical emergence. Shepherd’s aims, commitments, and historical context indicate that she holds an emergentist position on causation and the foundations of science, rejecting the popular reductionist paradigm of Early Modern philosophy. To motivate the project, I raise a puzzle about Shepherd's apparent commitment to the identity of causes and effects. This would entail that effects are their own causes, which violates Shepherd's fundamental principle that nothing can "begin of itself." I then argue that Shepherd endorses six metaphysical commitments that nearly all emergentists agree on, providing strong abductive evidence that she is thinking of causation from an emergentist perspective. This connection is also backed up by her historical context. Through an examination of Shepherd's texts and those of her interlocutors and correspondents, I argue that she saw the incorporation of chemical reactions into a theory of causation as a central problem in the foundations of science. This puts her in line with the British Emergentists of the 19th Century, who saw chemistry as the sharpest challenge to mechanistic reductionism.

At the start of his discussion of causation, Hume claims to demonstrate that simultaneous causation is absolutely impossible; all causes must precede their effects in time. I argue that considering Hume’s modal theory can reveal two important and previously unaddressed features of this argument. First, his modal metaphysics resolves one of the most pressing extant interpretive issues: how Hume is able to infer from the claim that it is possible for some object to be simultaneously caused to the claim that it is possible for all objects to be simultaneously caused. This step, I argue, is justified by Hume’s theory of relations. Based on an analysis of the representational capacities of the imagination in the Treatise, I develop a modal theory for relations that supports inferences of this kind. Second, his distinction between absolute and natural modality raises a problem that has not yet been identified in the literature. Hume is trying to conclude that something is metaphysically impossible, but one of his premises relies on a mere natural impossibility (that no object can begin to exist uncaused). I argue that this is an intractable problem: Hume cannot get the conclusion he wants because it depends on an equivocation between two strengths of modality.