The subjects of every state ought to contribute toward the support of the government, as nearly as possible, in proportion to their respective abilities; that is, in proportion to the revenue which they respectively enjoy under the protection of the state ....[As Henry Home (Lord Kames) has written, [a goal of taxation should be to] 'remedy inequality of riches as much as possible, by relieving the poor and burdening the rich.'
It is not very unreasonable that the rich should contribute to the public expence, not only in proportion to their revenue, but something more than in that proportion.