I noticed these two verses the other day:
The fear of the Lord is the beginning of wisdom. (Ps. 111:10)
The fool says in his heart, "There is no God." (Ps. 14:1, 53:1)
The Psalmist in these verses talks about two extremes: folly and wisdom, either a great knowledge or a lack of knowledge. Yet in each verse, they are related to something the affective realm. The fool is not merely one who says or thinks that God does not exist, but the one who says it in his heart, one who has denied God from the very core (Latin of heart: cor) of his being. Definitely not a good idea..
As for wisdom, it is obvious that one needs to know about God (the principle and cause of the order of all things) in order to be wise, yet the Psalmist does not speak about knowledge, but fear, which belongs to the affections. So before one can draw near to the Lord and eventually become wise, there must be some fear of the Lord, some interior disposition by which he can incline toward God and listen to him..
Here's an article on intellectual customs which makes a similar point about the beginning of the intellectual life: http://classicalhomeschooling.com/classical-homeschooling-fourth-issue/adlers-influence-on-thomas-aquinas-college/
And it's probably good to remember that a significant chunk of I-II of the Summa Theologiae is spent considering the passions/affections/emotions, since these are a integral part of us and the ordering of them (that is, the acquiring of virtue) is essential if we are to attain wisdom.
Blessed the pure of heart, for they shall see God. (Mt. 5)