In his “Platonic Theology on the Immortality of Souls” (1482), Marsilio Ficino defended the idea of the world’s universal animation. In this purpose, he especially developed a ‘Platonic’ interpretation of spontaneous generation, relying not only on the notions of Ideas and the World-Soul but also on his own theory of the ‘earth’s soul’ (anima terrae), which influenced a number of natural philosophers in the end of the Renaissance such as Giordano Bruno and Johannes Kepler. This study analyzes the Ficinian theory in the mirror of the criticism formulated by Fortunio Liceti in his “On the Spontaneous Generation of Living Beings” (1618).

1. Introduction
2. Liceti’s “De spontaneo viventium ortu” (1618)
3. Junior Platonicists and the World-Soul
4. Major Platonists and the Ideas
5. Ficino and the Earth’s Soul
6. Cicero’s “De natura deorum” as the source of Ficino?