De plantis

Life is found in animals and plants; but while in animalsit is clearly manifest, in plants it is hidden and less evident. But before we can assert the presence of life in plants, a long inquiry must be held as to whether plants possess a soul and a distinguishing capacity for desire and pleasure and pain. Now Anaxagoras and Empedocles say that they are influenced by desire; they also assert that they have sensation and sadness and pleasure. Anaxagoras declared that plants are animals and feel joy and sadness, deducing this from the bending of their foliage; while Empedocles held the opinion that sex has a place in their composition. Plato indeed declares that they feel desire only on account of their compelling need of nutriment. If this be granted, it will follow that they also feel joy and sadness and have sensation. I should also like to reach some conclusion as to whether they are refreshed by sleep and wake up again, and also whether they breathe, and whether they have sex through the mingling of the sexes or not. But the great diversity of opinion on these subjects involves too long an inquiry, and the best course is to pass over these topics and not to waste time on the unprofitable investigation of details. Some have asserted that plants have souls, because they have seen that they come to birth and receive nutriment and grow, and have the bloom of youth and the dissolution of old age—characteristics which nothing inanimate shares with plants; if plants possess these characteristics, they believed them also to be affected by desire.