Scottish philosopher. The daughter of the third early of Rosebery and largely self-taught, Shepherd was a friend of Charles Babbage. She published two major philosophical works: An Essay upon the Relation of Cause and Effect (1824) and Essays on the Perception of an External Universe, and Other Subjects (1827). The first is an attack on Hume on causation, apparently occasioned by an Edinburgh uproar over whether John Leslie could be a suitable candidate for a chair in mathemics, given that he adhered to Hume's views of causation, and was therefore likely to be an infidel and atheist. She was much admired by Whewell, who is supposed to have used her treatise as a textbook; Sir Charles Lyell, the geologist, called her an ‘unanswerable logician’.