medicine
The Natural Faculties (Powers of the Body)
δυνάμεις φυσικαί
Why does the body nourish and grow itself? Galen answers: each organ wields innate powers — to attract, hold, transform, and expel.
Galen taught that living bodies are not mere machines but are animated by inborn "faculties" — powers that belong to each organ and tissue. He named four key ones: an attractive power that draws in what the part needs, a retentive power that holds it, an alterative power that transforms it (as the stomach concocts food), and an expulsive power that voids what is useless. Against atomists who explained the body by blind matter in motion, Galen insisted these purposeful powers prove that Nature does nothing in vain.
Where this idea shows up
1 Greek sourceWhere to read it
- Quaestiones Convivales120 CEPlutarch· Chaeronea