Galen on the functional expression of the soul by the brain

Galen lived in the philosophical atmosphere of the Hellenistic era under the influence of the theological syncretism, the Aristotelian and Platonic doctrines, and the new tendencies of stoicism, skepticism and neo-Platonism and the preponderance of the mainstream of policy for a unilingual cospopolitan man. He attempted to associate the Hippocratic medical pragmatism with the stoicism and Neo-Platonism, accepting at the same time the majority of the Aristotelian doctrines. Galen based his medical principles on superb anatomical studies and detailed observations of the functions of the parts and organs of the body in animals. According to Galen the body is the instrument of the soul and it is adapted to the habits and faculties of the soul. The use of the various organs depends on the soul. Every soul on the other hand is the first realization of the human body serving it as an instrument. The functions of the soul are continuously renewed, since they are generated and grow by the steady production of the cerebral spirit (pneuma) under the influence of the respiration and blood flow. The human soul grows untill death, when it is consumed by the fever and the body perishes. The reasoning faculty of the soul is mortal since it is created by the mixture of various humors of the brain. Galen clamed that the anterior part of the brain is softer than the other areas and particular able to receive sensations, to form imaginations and to apprehend any kind of thoughts. However Galen attributed great importance in the posterior part, particularly the brain stem and the fourth ventricle for the maintenance of life. At the same time he attributed all the brain faculties to the interaction of the brain and its pneuma. The sensus communis is perceptive to new impressions and able to support the creation of new thoughts by the association of the current perceptions with those of the past. The coordinating action of the sensus communis depends ultimately upon the sense impressions. Abnormal sense perception may result to illusions and hallucinations. When the thinking faculty is paralyzed the patient suffers from anoia (dementia), whereas if the thinking movements are defective he suffers from moria or morosis. Galen stated that all the psychic organs require physical maintenance, a fact which highlights the psychosomatic integration of the human being. The degree of awareness depends mainly on the state and the condition of the brain itself. Memory is the retention and conservation of those impressions, which soul discerned at an earlier time. Memory can operate only at high levels of consciousness. Memory and reasoning can be lost at low levels of awareness, such as lethargos, stupor and coma.Virtue seems to require an act of good will. Reason must be trained in order to control the erroneous thoughts and the inappropriate behaviour. Emotional and rational activities are mutually related. Anger and desire are regarded as afflictions of the soul. They may be restrained and controlled by the judgment of the reason. Moreover the power of reason may modify the physical condition mainly by regulating the emotions. Galen considered that body and soul are in continuous and ceaseless mutual interaction. He attempted to correlate psychological traits with the humoral doctrine, claiming that the faculties of the soul correspond to the humoral composition of the body. When melancholic symptoms affect the brain faculties, then depression, fear and erroneous impressions arise along with the desire to die. Moreover depression and anxiety are the foremost manifestations of the toxic effect of black bile on the human brain. Dietary habits and physical therapy could modify the production of the black bile and ameliorate the psychological condition of the patients. Galen in addition to pharmaceutical treatment introduced psychotherapy, physical therapy and proper education, claiming that lifetime training of the reasoning power will eventually lead to a state of mental and physical health.

Key words: Galen, soul, brain, psychosomatic integration, Hellenistic medicine, philosophy.