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. (shrink)