I did contrive to say civil things to Dr. Brown; but the wonder of the crowd, and the persons who sucked us all in turn into their vortex, were Professor Spurzheim and Lady M. Shepherd. Her ladyship fairly threw down the gauntlet, and was as luminous, as deep, as clever in her observations and questions, and in her display of previous knowledge of Gall's theory and Hartley's, as any professor could have been, and convinced me, at least, that when Mr. Tierney had said, of Lady Mary, she was almost the best metaphysician he ever knew, and the most logical woman, by far, he ever met with, he was probably right. The professor looked alarmed, and put on his pins; and Lady Mary began her dialogue at ten, and it was not over at a little past twelve.
Dr. Brown listened occasionally, and with an anatomizing eye, for he does not like literary women; therefore a woman, entering his own arena, must have called forth all his reviewer bitterness. L. M. had assured Dr. B. our parties were mixed ones, and nothing like science or learning displayed; and on his first introduction he meets with a scene like this! (pp. 150-151)
This event occurred in late May of 1814, so Lady Mary was about twenty-seven at the time. The "Dr. Brown" is Thomas Brown; as Opie says of him, he is "the Dr. Brown, professor and lecturer on moral philosophy, the successor of Dugald Stewart, the Edinburgh Reviewer" (p. 150). Brown's best-known philosophical work is his Inquiry into the Relation of Cause and Effect, a defense of Hume. Lady Mary criticizes this work at great length in her An Essay upon the Relation of Cause and Effect, which is a brilliant attack on all Humean theories of causation. The "Professor Spurzheim" is Johann Spurzheim, the phrenologist, a former associate of Gall's who was primarily responsible for popularizing him, and, indeed, coined the word 'phrenology'. Shepherd no doubt raised more than a few serious questions about it.
When Opie saw Lady Mary next she was self-conscious about it: "She was nervous about her display on Sunday last; but I assured her she was thought to talk well, though I could have added, but not by Dr. Brown" (p. 152).
C. L. Brightwell, ed., Memorials of the Life of Amelia Opie
Thomas Brown, Inquiry into the Relation of Cause and Effect
Lady Mary Shepherd, An Essay upon the Relation of Cause and Effect
Johann Spurzheim, A View of the Elementary Principles of Education
[Cross-posted at Houyhnhnm Land]