Hume’s conclusion as to the practical attitude of the positivist toward life can best be stated in his own words (_Treatise_, Book I, Conclusion): “Shall we then establish it for a general maxim, that no refined or elaborate reasoning is ever to be received? If we embrace this principle, we run into the most manifest absurdities. If we reject it in favor of those reasonings, we subvert entirely the human understanding. We have, therefore, no choice left, but between a false reason and none at all. Most fortunately it happens that since reason is incapable of dispelling these clouds, nature suffices to that purpose, and cures me of this philosophical melancholy. I dine, I play a game of backgammon, I converse, and am merry with my friends.――No: If I must be a fool, as all who reason or believe anything certainly are, my follies shall at least be natural and agreeable. In all the incidents of life we ought still to preserve our skepticism. Where reason is lively and mixes itself with some propensity it ought to be assented to.” =The Origin of Ideas.= Locke did not proceed to the construction of his theory of knowledge until he had disclaimed at length his belief in the existence of innate ideas. Berkeley went further and made his polemic against the existence of all abstract ideas. Hume went still further and denied that any ideas existed except those derived from impressions. Locke’s attack upon innate ideas was an attack upon unverified tradition; Berkeley’s attack upon abstract ideas was an attack upon materialism; Hume made a general attack upon rationalism. The psychology of Hume is thus made simple. It is a cancellation of the factors incompatible with strict empiricism――the factors which he found in Locke and Berkeley. Hume’s empirical psychology is simply this: _every idea is the image or copy of an impression_. What is an impression? Impressions are of two classes: (1) sensations or outer impressions; (2) feelings or emotions or inner impressions. Impressions are never mistaken, because they always have a very lively and vivid character. What is an idea? It is the copy of an impression. An idea should never be mistaken for an impression, because it is fainter and more feeble than the impression of which it is the copy. For example, the sensation of yellow is more vigorous than the thought of yellow; the feeling of anger more vivid than the thought of anger. Impressions are simple and elemental. Can we go back of them and find their origin? We cannot. We receive impressions; echoes of impressions linger as ideas; ideas may be compounded with other ideas. Hume deals in his criticism mostly with the compounding or combining of ideas, but this is the sum and substance of his psychological analysis of our mental life. The following table will help us.