But man is subject to passions because he follows the order of nature. An affection can only be overcome by a stronger affection. Desire springing from the knowledge of good and evil can be restrained by desires originating in the affections by which we are agitated. Thus the effect of external causes on the mind may be far greater than that of the knowledge of good and evil. The desire springing from a knowledge of good and evil may be easily restrained by the desire of present objects.
Opinion exercises a more potent influence than reason.
Desire springing from joy preponderates over that springing from sorrow. Man is useful to man because two individuals of the same nature when in sympathy are stronger than one. Nothing could be so good for men as that all should so agree in everything as to form, as it were, a single body and mind, all seeking the good of all. Hence, men acting in accord with the dictates of reason, desire nothing for themselves but what they desire for all. This renders them just, faithful and honourable.