For anyone who checks out my Jackson Barwis link I urge them to read up to the point in Dialogue One where he writes these two paragraphs, which I find not only persuasive but poetic:
"The innate principles of the soul, continued he, cannot, any more than those of the body, be propositions. They must be in us antecedently to all our reasonings about them, or they could never be in us at all: for we cannot, by reasoning, create any thing, the principles of which did not exist antecedently. We can, indeed, describe our innate sentiments and perceptions to each other; we can reason, and we can make propositions about them; but our reasonings neither are, nor can create in us, moral principles. They exist prior to, and independently of, all reasoning, and all propositions about them.
When we are told that benevolence is pleasing; that malevolence is painful; we are not convinced of these truths by reasoning, nor by forming them into propositions: but by an appeal to the innate internal affections of our souls: and if on such an appeal, we could not feel within the sentiment of benevolence, and the peculiar pleasure attending it; and that of malevolence and its concomitant pain, not all the reasoning in the world could ever make us sensible of them, or enable us to understand their nature."