Rational animal

History

While the Latin term itself originates in scholasticism, it reflects the Aristotelian view of man as a creature distinguished by a rational principle. In the Nicomachean Ethics I.13, Aristotle states that the human being has a rational principle (Greek: λόγον ἔχον), on top of the nutritive life shared with plants, and the instinctual life shared with other animals, i. e., the ability to carry out rationally formulated projects. That capacity for deliberative imagination was equally singled out as man's defining feature in De anima III.11. While seen by Aristotle as a universal human feature, the definition applied to wise and foolish alike, and did not in any way imply necessarily the making of rational choices, as opposed to the ability to make them.

The Neoplatonic philosopher Porphyry defined man as a "mortal rational animal", and also considered animals to have a (lesser) rationality of their own.

The definition of man as a rational animal was common in scholastical philosophy. Catholic Encyclopedia states that this definition means that "in the system of classification and definition shown in the Arbor Porphyriana, man is a substance, corporeal, living, sentient, and rational".

In Meditation II of Meditations on First Philosophy, Descartes considers and rejects the scholastic concept of the "rational animal":

Shall I say 'a rational animal'? No; for then I should have to inquire what an animal is, what rationality is, and in this one question would lead me down the slope to other harder ones.