besides what I have already prov'd, that even in human nature no relation can ever alone produce any action; besides this, I say, it has been shewn, in treating of the understanding, that there is no connexion of cause and effect, such as this is suppos'd to be, which is discoverable otherwise than by experience, and of which we can pretend to have any security by the simple consideration of the objects. All beings in the universe, consider'd in themselves, appear entirely loose and independent of each other. 'Tis only by experience we learn their influence and connexion; and this influence we ought never to extend beyond experience. Thus it will be impossible to fulfil the first condition required to the system of eternal rational measures of right and wrong; because it is impossible to shew those relations, upon which such a distinction may be founded: And 'tis as impossible to fulfil the second condition; because we cannot prove a priori, that these relations, if they really existed and were perceiv'd, wou'd be universally forcible and obligatory.
But to make these general reflections more clear and convincing, we may illustrate them by some particular instances, wherein this character of moral good or evil is the most universally acknowledged. Of all crimes that human creatures are capable of committing, the most horrid and unnatural is ingratitude, especially when it is committed against parents, and appears in the more flagrant instances of wounds and death. This is acknowledge'd by all mankind, philosophers as well as the people; the question only arises among philosophers, whether the guilt or moral deformity of this action be discover'd by demonstrative reasoning, or be felt by an internal sense, and by means of some sentiment, which the reflecting on such an action naturally occasions. This question will soon be decided against the former opinion, if we can shew the same relations in other objects, without the notion of any guilt or iniquity attending them. Reason or science is nothing but the comparing of ideas, and the discovery of their relations; and if the same relations
