  Relaxing the criteria for inclusion in the “rationalist” camp also invites us to appropriately situate the rationalism of Scottish philosopher Mary Shepherd. Shepherd was a sharp critic of Hume’s endorsement of the causal system we might call “Malebranche without God”. Shepherd raised her objections to Hume’s theory on the basis of her commitment to the superiority of reason for knowledge, and in particular knowledge of the truths of causation. Here we see that she shares at least one characteristic of those typically ascribed to rationalists, the exaltation of reason over the senses in knowledge acquisition. In An Essay Upon the Relation of Cause and Effect (1824), Shepherd seeks to dismantle Hume’s causal theory of constant conjunction by arguing that we can indeed have intuitive knowledge that everything that exists requires a cause. Moreover, on her view, it is reason, not “custom” or “habit”, that is our chief guide in the understanding of our daily lives (27–28). Shepherd’s critique of Hume is important in its own right as a valuable contribution to the philosophical conversation of her age. It is also, however, representative of the way that the rationalist perspective was being articulated in the first quarter of the 19th century. As such, it marks a moment in the history of rationalism. Putting Shepherd into conversation with her fellow rationalists across time only serves to deepen and broaden our understanding of this line of thinking.