 The utmost justification for this unibility is the intellective soul’s natural capacity to know everything—an application of the Aristotelian principle that human beings desire to know everything. The rational soul is born (nata est) to know things in a twofold manner. The intellect can turn itself to the eternal, superior reasons, but can also turn its attention both to the images of sensible things received through the senses and abstracted from the phantasms (DSF 25; QLIII2S 24, 84). In so far as knowledge of material things depends on the use of the senses, the intellective soul can only fulfill its perfection by means of its union with the body (QLIIS 8, 32).