The medical philosophers are independent thinkers from medical training, who assume the Hippocratic-Galenic doctrine of typological differences based on constitution and temperament as the cause of psychological behaviour.

Gómez Pereira (1500-1560)

Gómez Pereira was a Castilian doctor who can be considered a precursor, almost a century ahead of Descartes. In his work ” Antoniana Margarita “, he makes thought the essence of the soul and defends the automatism of animals. The following sentence, previous to the famous Cartesian “cógito”, may give an idea: ” I know that I know something, and who knows exists: therefore I exist “.

Olive Sabuco from Nantes

Oliva’s work ” New philosophy of the nature of man ” (1587) was attributed to his father, Miguel, who was blind, which gives an idea of how unusual it is for a woman to sign a scientific work.

It is written in the form of a colloquium between three pastors and can be considered a treatise on the passions and their relationship with physiological life. It establishes the psycho-somatic or psycho-physiological interaction as an explanation of all kinds of human behaviour. It also defends the effectiveness of verbal therapy together with other organic therapies.

Juan Huarte de San Juan (1529-1585)

Patron of psychology in our country, he is one of the Spanish authors who has achieved greater universal projection through his work ” Examination of ingenuity for the sciences “, published in 1575. Huarte’s work was translated into Latin, English, French, Italian and Dutch, and was reprinted in some of these languages.

It starts from the doctrine that all souls are equal, with the cerebral temperament being the cause of man’s different abilities, according to the predominance in him of the primary qualities (heat, humidity and dryness). Dryness favours wisdom or intelligence, humidity favours memory, and heat favours imagination.

Huarte describes himself as a “natural philosopher” and as such he wants to look for the particular causes of any effect. While recognizing that God is the ultimate cause, he is interested in natural causes, and avoids explanations of a supernatural nature. It will be up to the scientist to discover the cause-effect relationship between things ” because there are ordered and manifest causes from which such an effect can be born “.

Huarte is an empiricist thinker. He therefore adopts the Aristotelian-Thomistic stance by defending the idea that if souls are equal, individual differences appear due to the difference between bodies. Matter thus becomes the differentiating principle. Huarte rejects the previous existence of a soul capable of knowing the Ideas. He recognises, however, that the soul – both in its rational aspect and in its sensitive and vegetative aspect – is wise, without being taught by anyone. It establishes a mediatic instrument in the brain regarding the abilities of the soul, which affects all kinds of skills.

He is the creator of a first evolutionary psychology by admitting that the temperament of childhood is more convenient to sensitive and vegetative souls than to rational ones, in order to gradually acquire a temperament more inclined to imagine, understand and remember. In the old ones, understanding dominates because they have a lot of dryness and little humidity, whose scarcity causes their little memory, while the young ones would have the opposite, that is why childhood would be more suitable for learning languages, an activity that according to Huarte depends on memory.

Huarte can also be considered a pioneer of eugenics , since the temperament would depend on the seed of the parents and, later, on the regime of life.

The notion of temperament goes back to Greek thinkers. Hippocrates , in the 5th century B.C., explains health as the balance of four humors: blood, black bile, yellow bile and phlegm. If heat and humidity (air) predominate, a blood temperament results. If the cold and dryness (earth), characteristic of phlegm, is phlegmatic; if the heat and dryness (fire), characteristic of yellow bile, the temperament will be choleric, and if the cold and dampness of black bile (water) predominates, the temperament will be melancholic. (See Table 1).

Huarte combines the theory of the Humours of Hippocrates with the powers of the “rational soul” established by Aristotle: memory, imagination and understanding.

The memory passively receives and retains the data. For the brain to be a good instrument of this faculty, humidity must predominate in it . The imaginative, according to the Aristotelian notion, is the one that writes in the memory the figures of things, and is in charge of introducing them and recovering them from memory. For the brain to be a good instrument of this faculty, heat must predominate in it: “Heat raises the figures and makes them boil, through which one discovers all that is to be seen in them”.

Understanding needs the brain to be dry and composed of very subtle and delicate parts. It is the task of understanding to infer, distinguish and choose.

These three powers are mutually exclusive: with memory and the predominance of humidity, understanding is lost, which requires dryness and heat, and vice versa. The one who has a great imagination will not be able to have much understanding either because the heat that it requires “consumes the most delicate part of the brain, and leaves it hard and dry”.

Huarte refutes Cicero’s opinion that all the arts could be achieved through study, as they are based on principles that can be learned. For Huarte there are three types of ingenuity : the intelligent, the memorable and the imaginative. Each trade, on the other hand, will require a certain type of ingenuity.

A preacher needs understanding to reach the truth, memory to quote others’ phrases and good imagination to be able to teach eloquently and attract attention, so a good preacher should have great understanding and a lot of imagination. However, since great imagination predisposes one to pride, gluttony and lust, he recommends that the preacher not be overly imaginative, since he could incur evil and drag the faithful into it.

A good lawyer or judge will need great memory to learn the many laws and good understanding to distinguish, infer, reason and choose . Although it is always preferable for a lawyer to have a lot of understanding and little memory than the opposite.

Medicine also needs good understanding and memory, although it requires the imagination of the clinical eye, the conjectures of medicine, and the right causes and remedies for each patient.

The military profession requires a certain amount of malice, which requires a special kind of imagination that confers the ability to guess the “tricks that come under some cover”. In his opinion the game of chess is one of the most imaginative games.

Finally, the office of king would find its ideal temperament in a ” temperate man “, that is to say, with a balanced or equilibrated temperament. This is accompanied by a hair that grows golden with age, and by grace, grace and a good figure. Other signs of this temperament are virtue and good manners.

If cold and wetness predominate in the engendered body, it will be a woman. In her life she will manifest poorly the qualities that the soul possesses to the highest degree. If heat and dryness predominate, a man will be born, whose qualities will be ability and ingenuity. Variations in the body’s temperament result in greater or lesser clumsiness in women and greater or lesser ingenuity and skill in men.

Huarte gathers from Aristotle the idea that desire, imagination and movements during the carnal act contribute to generate good children. According to this doctrine, wise parents tend to have foolish children, because they are clumsy for the sexual act, while the foolish and instinctive, being more skilful, can generate ingenious children.

Huarte is considered a pioneer in different fields: for Menéndez Pelayo is the father of phrenology ; he can also be considered the forerunner of the approach to differential psychology and professional orientation and selection. He is also a pioneer, as we said, of eugenics and the psychology of ages.