Galen's Nine Temperaments: The Missing Centre of the Four

In On Mixtures Galen laid out nine states of the body: one perfectly balanced centre and eight ways of leaning off it. The four temperaments everyone knows are only four of the eight, and the balanced ninth was the one he prized most.

Somewhere in the second book of On Mixtures, Galen stops describing patients and describes a man. This man's flesh is midway between hard and soft. His skin is neither hot nor cold to a hand laid on it, his build neither fat nor lean. He warms quickly to exercise and blushes easily. He is not sick, and Galen is not treating him. He is the measure. Galen calls him the best mixed body, the eukratos, the standard against which every other body in the book is judged.

That figure is the reason the four temperaments were never really four.

The scheme had a centre

Galen wrote Peri kraseon, known in Latin as De temperamentis, in Rome in the later second century. The word krasis means a blending, and the thing being blended is a set of paired qualities: hot and cold, dry and wet. Every living body is some mixture of them. One mixture is balanced, with no quality winning out. Galen calls this eukrasia, good mixture. Every other mixture is a dyskrasia, an imbalance, and he counts eight of them.

Four are simple. A body can run too hot, too cold, too dry, or too wet, with a single quality in excess while its opposite stays near neutral. Four are compound, two qualities pulling at once: hot and dry, hot and wet, cold and dry, cold and wet. Add the balanced centre and the total is nine. One point of health and eight ways of leaning off it.

Where the familiar four are hiding

The temperaments everyone knows are only the four compounds. Hot and dry is the choleric mixture, tied to yellow bile. Hot and wet is sanguine, tied to blood. Cold and dry is melancholic, tied to black bile. Cold and wet is phlegmatic, tied to phlegm. The wheel of four that later became a personality chart is simply Galen's four double imbalances, lifted out of a longer list and given names.

Galen himself was more cautious than the wheel suggests. He wrote mostly about qualities and humors and degrees, not about four fixed characters you could sort people into. The tidy named quartet hardened later, in the medieval schools and their handbooks, where it was easier to teach and easier to draw. If you want the longer story of how the humoral picture was assembled and passed down, it runs through Hippocrates and Galen and the wider history of the four humors.

The missing centre was the point

Here is what the simplification lost. For a physician, the eukratos was not one option among nine. It was the aim of the whole art. Health was good mixture, illness was mixture gone wrong, and treatment meant nudging a body back toward the balanced middle. The four simple imbalances and, above all, the temperate centre were the working part of the scheme, the part a doctor actually cared about. The four compounds were only the corners you tried to lead a patient away from.

So the popular version kept the corners and threw out the goal. It kept the four vivid types and dropped the one state Galen prized most, the person in whom nothing dominates. You can still meet the idea in a quiet way when you take the test and find your two strongest leanings sitting almost level. That near-level reading is the old centre showing through.

A blend is a step back toward it

This is why blends matter more than they first seem. When someone comes out as sanguine and phlegmatic in almost equal measure, the popular scheme has no word for it and treats it as a muddle between two boxes. Galen's scheme has an exact place for it. It is a body moving back toward eukrasia, away from any single compound and toward the balanced middle. A blend is not a failure to be a type. It is a partial return to the centre the four temperaments left out. There is a fuller account in the piece on temperament blends.

Why nine collapsed into four

The reasons are ordinary. Four is a shape that fits other fours: four seasons, four elements, four ages of life, four winds. The compounds could be lined up with all of them and drawn as a neat square. The temperate centre fits none of it. It has no season, no colour, no matching element, nothing to pin on the diagram. A thing that cannot be drawn tends to fall out of the drawing.

So the tradition kept the memorable four and let the subtler nine fade, and with the nine went its quiet ideal. It is worth remembering when the four temperaments are handed to you as the whole of the old theory. They are the four corners of a room whose centre was the part that mattered. Galen built the room around a man standing in the middle of it, perfectly balanced, and it is his own scheme that later forgot he was there.