E3DA3
Definition of an Emotion — Part III
Latin
Tristitia est hominis transitio a majore ad minorem perfectionem.
Explicatio: Dico transitionem. Nam lætitia non est ipsa perfectio. Si enim homo cum perfectione ad quam transit nasceretur, ejusdem absque lætitiæ affectu compos esset; quod clarius apparet ex tristitiæ affectu qui huic est contrarius. Nam quod tristitia in transitione ad minorem perfectionem consistit, non autem in ipsa minore perfectione, nemo negare potest quandoquidem homo eatenus contristari nequit quatenus alicujus perfectionis est particeps. Nec dicere possumus quod tristitia in privatione majoris perfectionis consistat nam privatio nihil est; tristitiæ autem affectus actus est qui propterea nullus alius esse potest quam actus transeundi ad minorem perfectionem hoc est actus quo hominis agendi potentia minuitur vel coercetur (vide scholium propositionis 11 hujus). Cæterum definitiones hilaritatis, titillationis, melancholiæ et doloris omitto quia ad corpus potissimum referuntur et non nisi lætitiæ aut tristitiæ sunt species.
English (Elwes 1883)
Pain is the transition of a man from a greater to a less perfection.
Explanation: I say transition: for pleasure is not perfection itself. For, if man were born with the perfection to which he passes, he would possess the same, without the emotion of pleasure. This appears more clearly from the consideration of the contrary emotion, pain. No one can deny, that pain consists in the transition to a less perfection, and not in the less perfection itself: for a man cannot be pained, in so far as he partakes of perfection of any degree. Neither can we say, that pain consists in the absence of a greater perfection. For absence is nothing, whereas the emotion of pain is an activity; wherefore this activity can only be the activity of transition from a greater to a less perfection--in other words, it is an activity whereby a man's power of action is lessened or constrained (cf. III. xi. note). I pass over the definitions of merriment, stimulation, melancholy, and grief, because these terms are generally used in reference to the body, and are merely kinds of pleasure or pain.
Modern English
Sadness is a person's transition from a greater to a lesser perfection.
Explanation. I say transition. For joy is not perfection itself. If a person were born with the perfection to which they pass, they would possess it without the affect of joy. This is more clearly apparent from the contrary affect, sadness. No one can deny that sadness consists in the transition to a lesser perfection, not in the lesser perfection itself; for a person cannot be saddened insofar as they partake of some perfection. Nor can we say that sadness consists in the privation of a greater perfection, since privation is nothing; but the affect of sadness is an act, and therefore it can be nothing other than the act of passing to a lesser perfection, that is, the act by which a person's power of acting is diminished or restrained (E3P11S). As for the definitions of cheerfulness, titillation, melancholy, and pain, I leave these aside, since they are most properly referred to the body and are nothing but species of joy or sadness.