Psychology is one of the youngest sciences, but that does not mean that it has not been developed over centuries, or even millennia.

In fact, some of the great questions you are trying to answer began to generate theories more than 2,000 years ago. The theory of the four moods, related to the different personality classes that we can find in human beings, is an example of this. It was proposed by the Greek Hippocrates.

The origins of the theory of the four humors

By the fifth century BC, Ancient Greece, which was the cradle of what would become Western civilization, was already beginning to forge theories about why we are the way we are and do what we do. In fact this kind of theoretical proposals had also appeared before in other areas of the planet, but the Greek case was of special importance because there the technical advances of Asia and Egypt were joined with the philosophy and the powerful cultural and philosophical activity of the area.

Greece was a region where knowledge was disseminated much more freely than, for example, in the Persian Empire, where the teaching of writing was highly centralized and used primarily for trade and administration.

This explains why, in only three centuries, Ancient Greece could become a reference point for the development of philosophy and the sciences (in its most embryonic phase). But Greek science, like what was happening in other parts of the world, was mixed with religions and a vision of the world still based on old myths. That is what explains the appearance of the theory of the four moods .

What is the four moods theory?

Originally, the theory of the four humors, first proposed by the Greek physician Hippocrates, was based on the assumption that the human body is composed of four basic substances (the so-called “humors”) and that the balances and imbalances in the amounts of these substances in an organism determine the health of the organism.

These moods corresponded to the elements air, fire, earth and water , which a few years earlier had been pointed out by the philosopher Empedocles as the raw materials of all that exists.

So the theory of the four humors was not isolated from the way reality was understood in Ancient Greece, but it was connected with a belief in the origin of the planet and of the cosmos in general; supposedly, all reality was a combination of different quantities of these four elements, and from this the theory of the four humors emerged. The properties of these four elements, in turn, were reflected in the characteristics of the four humors which, according to Hippocrates, flowed through the human body.

The different moods according to Hippocrates

And what were these moods? Each of them expresses specific physical characteristics, in line with the thinkers of the time, who tried to describe reality based on everyday and easily identifiable material properties.Explained far above, they were these:

1. Black bile

Substance linked to the element earth , whose properties were cold and dry.

2. Yellow bile

Humor corresponding to the fire element . Its qualities were warmth and dryness.

3. Blood

The substance linked to the element of air , whose properties were warmth and humidity.

4. Phlegm

The water-related substance , whose properties are cold and wet.

Moods and Personality

For Hippocrates and a good number of the physicians who assimilated the theories of the former during the following centuries, the theory of the four humors offered a basis on which to work in medicine, however precarious it might be . Thus, many treatments for diseases consisted of modifying the diet of patients so that, by eating certain foods, their humoral levels were balanced. In some cases, bleeding was performed to allow patients to lose fluid for the same purpose.

But this basis for medicine was not the only thing that emerged from the four-humour theory. Some thinkers expanded it to be able to explain not only people’s health, but also trends in their behavior and mental life. Among these researchers, Galen of Pergamon, a Roman physician and philosopher born in the second century A.D., stood out .

Galen’s ideas

For Galen, the imbalances in the amounts of humors had an influence on the way we think, feel and act . In other words, their proportions were the basis of people’s temperament. Naturally, each individual has levels of moods that are rarely fully proportionate, and that is what explains the differences in personality.

When black bile humor predominates, for example, I thought that the person tended to be melancholic and prone to sadness and the expression of intense emotions, while in individuals with a higher proportion of phlegm than other substances, their temperament would be characterized by their tendency to rationally analyze situations and their ease in keeping calm.

The personality types were as follows

As we have seen, according to this humoral vision of the human being, health was found in the balance of these substances (the logic of balances between fundamental elements was very frequent at that time). It was believed that some illnesses or special situations could make this disproportion grow, aggravating the person’s health and/or making his temperament more extreme and discordant with respect to the way of being of others.

1. Sanguine

It corresponded to cheerful and optimistic people , with a tendency to express their affection for others and with self-confidence. It corresponded to the substance of blood.

2. Melancholic

Temperament defined by the presence of a large amount of black bile, its associated temperament is sad, with artistic sensitivity and easy to move .

3. Phlegmatic

Corresponding to the mood of phlegm, people associated with this temperament would be cold and rational .

4. Choleric

Temperament related to the yellow bile, would be expressed in passionate, easily angry people with great energy .

The theory of the four temperaments, today

The theory born with Empedocles and Hippocrates and expanded by Galen was one of the pillars of medicine until the time of the Renaissance. Beyond this historical stage, however, it has inspired some psychologists interested in the study of individual differences and personality, among them Hans Eysenck.

It should be noted that this classification system has no scientific value ; in any case, it can serve to inspire when developing theories and hypotheses that, in time, will come to have empirical evidence in their favour.