Thomas Aquinas

“ On the other hand, the desire or study in pursuing the knowledge of truth may be right or wrong. First, when one tends by his study to the knowledge of truth as having evil accidentally annexed to it, for instance those who study to know the truth that they may take pride in their knowledge. ”

“ On the contrary, Augustine says (De Vera Relig. 38) that "concupiscence of the eyes makes men curious." Now according to Bede (Comment. in 1 Jn. 2:16) "concupiscence of the eyes refers not only to the learning of magic arts, but also to sight-seeing, and to the discovery and dispraise of our neighbor's faults," and all these are particular objects of sense. Therefore since concupiscence of the eves is a sin, even as concupiscence of the flesh and pride of life, which are members of the same division (1 Jn. 2:16) , it seems that the vice of curiosity is about the knowledge of sensible things. ”

“ In the second place, it is directed in a manner special to man, to intellective knowledge, whether speculative or practical. Accordingly to employ study for the purpose of knowing sensible things may be sinful in two ways. First, when the sensitive knowledge is not directed to something useful, but turns man away from some useful consideration. ”