In the Preface he indicates the general scope of the work. Morality has its root in the Common Nature of Man; a scheme of Morality must conform to the _Common Sense_ of mankind, in so far as that is consistent with itself. Now, this Common Sense of Mankind has in every age led to two seemingly opposite schemes of Morality, the one making _Virtue_, and the other making _Pleasure_, the rule of action. On the one side, men urge the claims of Rectitude, Duty, Conscience, the Moral Faculty; on the other, they declare Utility, Expediency, Interest, Enjoyment, to be the proper guides. Both systems are liable to objections. Against the scheme of Pleasure, it is urged that we never, in fact, identify virtue as merely useful. Against the scheme of Virtue, it is maintained that virtue is a matter of opinion, and that Conscience varies in different ages, countries, and persons. It is necessary that a scheme of Morality should surmount both classes of objections; and the author therefore attempts a reconciliation of the two opposing theories. He prepares the way by asking, whether there are any actions, or qualities of actions, universally approved; and whether there are any moral rules accepted by the Common Sense of mankind as universally valid? The reply is that there are such, as, for example, the virtues termed Veracity, Justice, Benevolence. He does not enquire _why_ these are approved; he accepts the fact of the approval, and considers that here we have the basis of a Moral System, not liable to either of the opposing objections above recited. He supposes, however, that the alleged agreement may be challenged, _first_, as not existing; and _next_, as insufficient to reason from. 1. It may be maintained that the excellence of the three virtues named is not universally assented to; departures from them being allowed both in practice and in theory. The answer is, that the principles may be admitted, although the interpretation varies. Men allow Fidelity and Kindness to be virtues, although in an early stage of moral progress they do not make the application beyond their own friends; it is only at an advanced stage that they include enemies. The Romans at first held stranger and enemy to be synonymous; but afterwards they applauded the sentiment of the poet, _homo sum_, &c. Moral principles must be what we approve of, when we speak in the name of the whole human species. 2. It may be said that such principles are too vague and loose to reason from. A verbal agreement in employing the terms _truthful, just, humane_, does not prove a real agreement as to the actions; and the particulars must be held as explaining the generalities. The author holds this objection to be erroneous; and the scheme of his work is intended to meet it. He proceeds as follows:--