E4Cap30
Chapter — Part IV
Latin
Cum igitur res illæ sint bonæ quæ corporis partes juvant ut suo officio fungantur et lætitia in eo consistat quod hominis potentia quatenus mente et corpore constat, juvatur vel augetur, sunt ergo illa omnia quæ lætitiam afferunt, bona. Attamen quoniam contra non eum in finem res agunt ut nos lætitia afficiant nec earum agendi potentia ex nostra utilitate temperatur et denique quoniam lætitia plerumque ad unam corporis partem potissimum refertur, habent ergo plerumque lætitiæ affectus (nisi ratio et vigilantia adsit) et consequenter cupiditates etiam quæ ex iisdem generantur, excessum; ad quod accedit quod ex affectu id primum habeamus quod in præsentia suave est nec futura æquali animi affectu æstimare possumus. Vide scholium propositionis 44 et scholium propositionis 60 partis IV.
English (Elwes 1883)
As, therefore, those things are good which assist the various parts of the body, and enable them to perform their functions; and as pleasure consists in an increase of, or aid to, man's power, in so far as he is composed of mind and body; it follows that all those things which bring pleasure are good. But seeing that things do not work with the object of giving us pleasure, and that their power of action is not tempered to suit our advantage, and, lastly, that pleasure is generally referred to one part of the body more than to the other parts; therefore most emotions of pleasure (unless reason and watchfulness be at hand), and consequently the desires arising therefrom, may become excessive. Moreover we may add that emotion leads us to pay most regard to what is agreeable in the present, nor can we estimate what is future with emotions equally vivid. (IV. xliv. note, and lx. note.)
Modern English
Since those things are good that assist the parts of the body in performing their functions, and since joy consists in the fact that a person's power — insofar as he is composed of mind and body — is aided or increased, all things that bring joy are good. Yet because things do not act for the sake of bringing us joy, and because their power of acting is not calibrated to our advantage, and because joy is mostly referred to one part of the body more than the rest, most joy-affects — unless reason and alertness are present — and consequently the desires generated by them will tend to excess. To this must be added that we are led by affect to value most what is agreeable now, and cannot weigh what is future with the same intensity of feeling. See the Scholium of Proposition 44 and the Scholium of Proposition 60 of Part IV (E4P44S) (E4P60S).