It is much harder to make this distinction when the action accords with duty and the subject has besides a direct inclination to it. For example, it is always a matter of duty that a dealer should not over charge an inexperienced purchaser; and wherever there is much commerce the prudent tradesman does not overcharge, but keeps a fixed price for everyone, so that a child buys of him as well as any other. Men are thus honestly served; but this is not enough to make us believe that the tradesman has so acted from duty and from principles of honesty: his own advantage required it; it is out of the question in this case to suppose that he might besides have a direct inclination in favour of the buyers, so that, as it were, from love he should give no advantage to one over another.

Accordingly the action was done neither from