E4P43D
Demonstration — Part IV
Latin
Titillatio est lætitia quæ quatenus ad corpus refertur, in hoc consistit quod una vel aliquot ejus partes præ reliquis afficiuntur (vide ejus definitionem in scholio propositionis 11 partis III) cujus affectus potentia tanta esse potest ut reliquas corporis actiones superet (per propositionem 6 hujus) eique pertinaciter adhæreat atque adeo impediat quominus corpus aptum sit ut plurimis aliis modis afficiatur adeoque (per propositionem 38 hujus) mala esse potest. Deinde dolor qui contra tristitia est, in se solo consideratus non potest esse bonus (per propositionem 41 hujus). Verum quia ejus vis et incrementum definitur potentia causæ externæ cum nostra comparata (per propositionem 5 hujus) possumus ergo hujus affectus infinitos virium concipere gradus et modos (per propositionem 3 hujus) atque adeo eundem talem concipere qui titillationem possit coercere ut excessum non habeat et eatenus (per primam partem propositionis hujus) efficere ne corpus minus aptum reddatur ac proinde eatenus erit bonus. Q.E.D.
English (Elwes 1883)
Localized pleasure or stimulation (titillatio) is pleasure, which, in so far as it is referred to the body, consists in one or some of its parts being affected more than the rest (see its Definition, III. xi. note); the power of this emotion may be sufficient to overcome other actions of the body (IV. vi.), and may remain obstinately fixed therein, thus rendering it incapable of being affected in a variety of other ways: therefore (IV. xxxviii.) it may be bad. Again, grief, which is pain, cannot as such be good (IV. xli.). But, as its force and increase is defined by the power of an external cause compared with our own (IV. v.), we can conceive infinite degrees and modes of strength in this emotion (IV. iii.); we can, therefore, conceive it as capable of restraining stimulation, and preventing its becoming excessive, and hindering the body's capabilities; thus, to this extent, it will be good. Q.E.D.
Modern English
Localized pleasure is joy that, insofar as it is referred to the body, consists in one or a few of its parts being affected more than the rest (see its definition in the Scholium of E3P11). The power of this affect can be so great as to overwhelm the other actions of the body (E4P6) and adhere to it persistently, preventing the body from being capable of being affected in many other ways. Therefore (E4P38) it can be bad. Now pain, which is sadness, cannot on its own be good (E4P41). But because its force and increase is determined by the power of an external cause compared with our own (E4P5), we can conceive of endless degrees and modes of strength in this affect (E4P3). We can therefore conceive of it as strong enough to restrain localized pleasure so that it does not become excessive, and to that extent (E4P43) to prevent the body from being rendered less capable. To that extent, then, pain is good. Q.E.D.