The ontological necessity of soul according to Marsilio Ficino
(Rodrigo Peñaloza, 16/4/2017)

Here I present quite succinctly the neoplatonic argument for the existence of soul as summarized by Marsilio Ficino (1433–1499) in his Theologia Platonica de Immortalitate Animorum. The main line of the argument relies on Aristotle’s four causes.

There are four kinds of causes, according to Aristotle: efficient, final, material, and formal. When applied to Man, the efficient cause is Nature, the final cause is happiness, the material cause is body, and the formal cause is the soul. As pointed out by Marsilio Ficino:

Physicists [those who investigate or think about Nature] enumerate four causes: efficient, final, material, and formal. The efficient cause of man is universal Nature and man; the final cause is human happiness; the material cause is body, and the formal one is soul”. (Quattuor naturalium rerum causae a physicis numerantur, efficiens, finis, materia, forma. Efficiens hominis causa est natura universalis et homo; finis humana felicitas; materia corpus; forma est anima). — Marsilio Ficino, Theologia Platonica de Immortalitate Animorum, V, cap. 5, 1. (Insertion in brackets is mine).

In the ancient texts, the concept of soul is given by the anima or ψυχή (psyché) in the Aristotelian sense of animic principle, vital force, which is divided into vegetative, animal, and rational soul. If something exists without cause, it is said to exist per se. Only God is causeless, thus only God exists per se. On the other hand, body needs all four causes, because of its passive nature, often symbolized by the image of a receptacle or cup (patera, κράτηρ [kráter]) ready to receive. Then matter exists “omnino per alia”, absolutely through other things.

God and Matter are, therefore, two opposite extremes in causal terms: while God is causeless, Matter needs them all. Then, there must be something between God and Matter, something which is neither per se neither omnino per alia. This intermediate being is soul (anima). Indeed, as Marsilio Ficino writes:

The third essence, though independent of matter — made, nevertheless, far from God and close to matter -, somehow tends to it [i.e., matter], and because of such tendency, it is called soul. In spite of it, it does not depend on matter”. (Essentia tertia, licet a materia non dependeat, tamen a deo facta longinquior et propinqua materiae, ad eam quodammodo inclinatur, ob quam inclinationem anima nuncupatur. Et licet inclinetur, non tamen ab ipsa dependet). — Marsilio Ficino, Theologia Platonica de Immortalitate Animorum, V, cap. 5, 5.