_Not peculiar to this Department of the Science._--The difficulty in question, however, is one which, in reality, pertains to all mental science, and not to this department of it alone; and so Hume, in the passage cited by Mr. Stewart, seems to intend. It is true that while we are under the influence of any exciting emotion, we are in no mood, and in no suitable state to observe, with critical eye, the workings of our own minds; neither are we in any condition to do so when engaged in the less exciting, but not less absorbing _intellectual_ occupation of reasoning, or imagining, or remembering. The moment we begin to observe ourselves as thus engaged, the mind is no longer employed as before, the experiment which we wish to observe is interrupted, and instead of reasoning, imagining, or remembering, we are only observing ourselves. Our only resource, in either case, is to turn back and gather up, as well as we can from _memory_, the data of our mental activity and condition while thus and thus employed. And this we can do with regard to the action of the sensibilities, as well as of the intellect, provided only the degree of emotion and excitement is not so great as to interfere with the present consciousness, and so with the subsequent recollection of what was passing in our own minds. _Sources of Information._--Nor are we dependent entirely on self-observation. Our sources of information are twofold, the observation of our own minds, and of others. From the latter source we may learn much of the nature of this department of mental action. The sensibilities of others are more open to our inspection, and less readily mistaken, than their intellectual states. Nor do we meet, in this case, with the same difficulty; for however excited and incapable of self-inspection, at the moment, the subject of any strong emotion or passion may be, the spectator, at least, is able to observe the effect of that passion, and note its phenomena, with calm and careful eye. CHAPTER II. ANALYSIS AND CLASSIFICATION OF THE SENSIBILITIES. _Certain Distinctions may be noticed._--Including, under the term sensibility, according to the definition already given, whatever is of the nature of _feeling_, in distinction from thought or cognition, and limiting the term also to feelings strictly _mental_, in distinction from merely physical sensation, it is obvious that there are certain leading distinctions still to be observed in this class of our mental states, certain great and strongly marked divisions or differences, by which we shall do well to be guided in our arrangement and classification of them. Our feelings are many and various; it is impossible to enumerate or classify them with perfect precision; yet there are certain points of resemblance and difference among them, certain groups or classes into which they naturally divide themselves.