Physiognomy's basic claim, that stable features of the face and body reveal a person's inner character, has an unusually long continuous history in Western thought. The earliest surviving systematic treatment, the Physiognomonica, attributed to Aristotle's school rather than to Aristotle himself, argued that a person's character could be inferred by comparing their features to those of animals whose temperament was already assumed, a lion-like brow supposedly signaling courage, and so on; the method combined careful, almost naturalistic observation with reasoning that modern readers would recognize as circular. The practice persisted through antiquity and the Middle Ages as a minor branch of natural philosophy, taken up again seriously in the Renaissance by writers including Giambattista della Porta, whose 1586 De Humana Physiognomonia illustrated human faces alongside animal comparisons in the same tradition.
Physiognomy reached its widest audience with Johann Kaspar Lavater, a Swiss pastor whose four-volume Physiognomische Fragmente, published from 1775 to 1778, was read across Europe, including by Goethe, Schiller, and Kant, and went through more than fifty editions and translations. Lavater treated physiognomy as a serious moral and even religious discipline, a way of discerning God's design legible in the human face, and his enormous popularity helped keep the practice culturally significant even as its scientific standing remained shaky throughout. That same era also saw physiognomy's darker turn, as its logic of reading fixed inner worth from outward appearance fed directly into nineteenth century racial pseudoscience and, through Cesare Lombroso's criminal anthropology, into claims that facial and cranial features could mark someone as a born criminal.