The following excerpt from Hume's An Enquiry Concerning the Principles of Morals indicates the 'scientific' path he will follow to uncover the foundation of Ethics:

"we shall endeavour to follow a very simple method: We shall analyse that complication of mental qualities, which form what, in common life, we call PERSONAL MERIT: We shall consider every attribute of the mind, which renders a man an object either of esteem and affection, or of hatred and contempt; every habit or sentiment or faculty, which, if ascribed to any person, implies either praise or blame, and may enter into any panegyric or satire of his character and manners. The quick sensibility, which, on this head, is so universal among mankind, gives a philosopher sufficient assurance, that he can never be considerably mistaken in framing the catalogue, or incur any danger of misplacing the objects of his contemplation: He needs only to enter into his own breast for a moment, and consider whether or not he should desire to have this or that quality ascribed to him, and whether such or such an imputation would proceed from a friend or an enemy. The very nature of language guides us almost infallibly in forming a judgment of this nature; and as every tongue possesses one set of words which are taken in a good sense, and another in the opposite, the least acquaintance with the idiom suffices, without any reasoning, to direct us in collecting and arranging the estimable or blameable qualities of men. The only object of reasoning is to discover the circumstances on both sides, which are common to these qualities; to observe that particular in which the estimable qualities agree on the one hand, and the blameable on the other; and thence to reach the foundation of ethics, and find those universal principles, from which all censure or approbation is ultimately derived. As this is a question of fact, not of abstract science, we can only expect success, by following the experimental method, and deducing general maxims from a comparison of particular instances. The other scientifical method; where a general abstract principle is first established, and is afterwards branched out into a variety of inferences and conclusions, may be more perfect in itself, but suits less the imperfection of human nature, and is a common source of illusion and mistake in this as well as in other subjects. Men are now cured of their passion for hypotheses and systems in natural philosophy, and will hearken to no arguments but those which are derived from experience. It is full time they should attempt a like reformation in all moral disquisitions; and reject every system of ethics, however subtle or ingenious, which is not founded on fact and observation."

The following excerpt from David Hume's Enquiry describes the moral qualities that one would naturally 'see' in a person. The color coded sections exemplify the following categories: (1) qualities useful to others, (2) qualities useful to the person himself, (3) qualities immediately agreeable to others, and (4) qualities immediately agreeable to the person himself.

What so natural, for instance, as the following dialogue? You are very happy, we shall suppose one to say, addressing himself to another, that you have given your daughter to Cleanthes. (1) He is a man of honour and humanity. Every one, who [knows] him, is sure of fair and kind treatment. (2) I congratulate you too, says another, on the promising expectations of this son-in-law; whose assiduous application to the study of the laws, whose quick [understanding] and early knowledge both of men and business, prognosticate the greatest honours and advancement. You surprise me, replies a third, when you talk of Cleanthes as a man of business and application. I met him lately in a circle of the [liveliest] company, and (3) he was the very life and soul of our conversation: so much ingenious knowledge so genteelly delivered, I have never before observed in any one. You would admire him still more, says a fourth, if you knew him more familiarly. (4) That cheerfulness, which you might remark in him, is not a sudden flash struck out by company: it runs through the whole tenor of his life, and preserves a perpetual serenity on his countenance, and tranquillity in his soul. He has met with severe trials, misfortunes as well as dangers; and by his greatness of mind, was still superior to all of them.

To appreciate Hume's point, imagine that you are a personnel manager and that you are looking over two sets of letters of recommendation. One set contains a list of postive qualities, the other a list of their opposites. Which person would you hire and how would you defend your decision?