"Mysticism consists, according to a beautiful definition I find in Plotinus], in seeing with closed eyes [...] in seeing with the eyes of the soul, while the eyes of the body are closed. The essential phenomenon of mysticism is what is called ecstasy, a state in which, with all communication with the external world interrupted, the soul has the sense of communicating with an internal object, which is the infinite being, God. (La psicologia del misticismo, pp. 58-59)"