Gersonides on Jacob's Pathognomic Dream

Levi ben Gershom (Gersonides, 1288–1344), scientist and philosopher, authored an extensive commentary on the Pentateuch, where he applies his scientific expertise and inquisitiveness much as he does in his other writings. Following Maimonides, he interprets the narrative of Genesis 32.25–30, which describes the patriarch Jacob's mysterious wrestling match with an unnamed opponent, leaving Jacob with a sensible limp, as a prophetic dream. Going beyond Maimonides, Gersonides inquires as to how a dream could induce an orthopedic injury, and suggests, as one avenue, that the dream was pathognomic: Jacob acted out in a dream the tussle he feared he would have with his brother Esau. Though "medical dreams" were much discussed in premodern medicine, and "sleepfighting" was described by some Christian contemporaries, Gersonides' analyses stand out in their originality and detail.