There was no formal discipline called psychology in the Middle Ages, but a number of medieval writers, particularly those from the thirteenth century, discussed concerns similar to those of present-day psychologists. More important, at least a few, for example, Avicenna and Albertus Magnus (1193-1280), seem to have been genuinely interested in psychological theory It is possible to discern at least two important psychological traditions in the writing of this period: a medical and a philosophical one, both stemming from ancient predecessors.
The medical tradition stemmed from the works of ancient physicians such as Hippocrates of Cos (c. 460-377 BCE), Galen (c. 130-200 CE), and Caelus Aurelianus (c. 255-320 CE). This tradition was carried on by Islamic and Jewish physicians such as Haly Abbas (died c. 994 CE), Avicenna, Averroes, and Maimonides. Constantinus Africanus (c. 1015-1087 CE) translated a number of Arabic medical texts into Latin, and later Christian physicians (e.g., st. Hildegard of Bingen, 1098-1179 CE; Arnold of Villanova, c. 1234-1311 CE) added their own ideas. From the point of view of psychology, the medical tradition is probably most important for its views on mental illness, but the theory of the humors and the theory of the inner senses both arose from this tradition as well.
The philosophical tradition clearly originated with Plato (c. 427-347 BCE), and Aristotle (c. 384-322 BCE), with the latter predominant in the later Middle Ages. In Christian Europe, the thinking of St. Augustine (354-430 CE) was also of great importance, and ensured that the European philosophical tradition also had a strong religious element. A number of thirteenth-century philosophers who were also members of religious orders wrote about psychological issues, paying particular attention to perception, cognitive psychology, emotions, and the will. Such writers included Albertus Magnus, St. Thomas Aquinas (1225-1274 CE), Roger Bacon (1214-1292 CE), and William of Ockham (c. 1285-1349 CE). The philosophical tradition, especially Aristotle’s account, also provided the framework for the medieval view of the human being as a whole.
It would be a mistake to see the medical and philosophical traditions as conflicting. Avicenna and Averroes were exponents of both traditions, and although medieval Christians were sometimes easier to assign to one or another tradition, educated people were often well versed in both. The career of Petrus Hispanus (c. 1215-1277 CE) serves as an example. He received medical training, wrote widely on medical, philosophical, and philosophical issues, and became personal physician to Pope Gregory X; after Gregory’s death, he became pope himself (John XXI).
Medieval writers discussed a variety of psychological topics. For example, the theologian Aquinas gave a detailed theory of the emotions. Most ancient theorists had held to theories of vision in which some quality was emitted by the eyes. Islamic scholars such as Avicenna and Alhazen (c. 965-1039 CE) pointed out the weaknesses of such theories and produced coherent accounts of visual perception in which the eyes were recipients of information. The remainder of this article concentrates on medieval theories of cognitive psychology, an area scholars of the time saw as of central significance, and on ideas about mental illness, because these have so often been misrepresented in modern times.