Thomas Aquinas,
Summa Theologiae — Question 156 - OF INCONTINNENCE…
“ On the other hand, ignorance in the reason sometimes follows the inclination of the appetite, and then such like ignorance, the greater it is, the graver the sin, because the inclination of the appetite is shown thereby to be greater. Now in both the incontinent and the intemperate man, ignorance arises from the appetite being inclined to something, either by passion, as in the incontinent, or by habit, as in the intemperate. ”
