Next he shows how, in the rational or intellectual recognition of naturally existent relations amongst things (he always means persons chiefly), there is contained an obligation.  When God, in his Omniscience and absolute freedom from error, is found determining his Will always according to this eternal reason of things, it is very unreasonable and blameworthy in the intelligent creatures whom he has made so far like himself, not to govern their actions by the same eternal rule of Reason, but to suffer themselves to depart from it through negligent misunderstanding or wilful passion.  Herein lies obligation:  a man ought to act according to the Law of Reason, because he can as little refrain from assenting to the reasonableness and fitness of guiding his actions by it, as refuse his assent to a geometrical demonstration when he understands the terms.  The original obligation of all is the eternal Reason of Things; the sanction of Rewards and Punishments (though ’truly the most effectual means of keeping creatures in their duty’) is only a secondary and additional obligation.  Proof of his position he finds in men’s judgment of their own actions, better still in their judgments of others’ actions, best of all in their judgment of injuries inflicted on themselves.  Nor does any objection hold from the ignorance of savages in matters of morality:  they are equally ignorant of the plainest mathematical truths; the need of instruction does not take away the necessary difference of moral Good and Evil, any more than it takes away the necessary proportions of numbers.  He, then, instead of deducing all our several duties as he might, contents himself with mentioning the three great branches of them, (a) Duties in respect of God, consisting of sentiments and acts (Veneration, Love, Worship, &c.) called forth by the consideration of his attributes, and having a character of Fitness far beyond any that is visible in applying equal geometrical figures to one another, (b) Duties in respect of our Fellow-creatures: (1) Justice and Equity, the doing as we would be done by.  Iniquity is the very same in Action, as Falsity or Contradiction in Theory; what makes the one absurd makes the other unreasonable; ’it would be impossible for men not to be as much (!) ashamed of doing Iniquity, as they are of believing Contradictions;’ (2) Universal Love or Benevolence, the promoting the welfare or happiness of all, which is obligatory on various grounds:  the Good being the fit and reasonable, the greatest Good is the most fit and reasonable; by this God’s action is determined, and so ought ours; no Duty affords a more ample pleasure; besides having a ‘certain natural affection’ for those most closely connected with us, we desire to multiply affinities, which means to found society, for the sake of the more comfortable life that mutual good offices bring. [This is a very confused deduction of an obligation.’] (c) Duties in respect to our Selves, viz., self-preservation, temperance, contentment, &c.; for not being authors of our being, we have no just power or authority to take it away directly, or, by abuse of our faculties, indirectly.