3p59d.md (551B)
1 All emotions can be referred to desire, pleasure, or 2 pain, as their definitions, already given, show. Now by pain we 3 mean that the mind's power of thinking is diminished or checked 4 (III. xi. and note); therefore, in so far as the mind feels 5 pain, its power of understanding, that is, of activity, is 6 diminished or checked (III. i.); therefore, no painful emotions 7 can be attributed to the mind in virtue of its being active, but 8 only emotions of pleasure and desire, which (by the last Prop.) 9 are attributable to the mind in that condition. Q.E.D. 10 11