But there is another phenomenon in our mental history which has a direct bearing on the nature and succession of our conceptions. When any conception, through the influence of desire or emotion, becomes the prominent object, immediately other objects with which this has been associated in past experience begin to return and gather around it in new combinations. Thus a new picture is presented before the mind, from which it again selects an object according as _desire_ or _emotion_ regulates, which, under this influence, grows vivid and distinct. Around this new object immediately begin to cluster its past associates, till still another scene is fresh arrayed before the mind. In these new combinations, those objects which are least interesting continually disappear, while those most interesting are retained to form a part of the succeeding picture. Thus, in every mental picture, _desire_ or _emotion_ seems to call forth objects which start out, as it were, in bold relief from all others, and call from the shade of obscurity the companions of their former existence, which gather around them in new and varied combinations. Thus it is shown that the chief mode by which we regulate the nature and succession of our thoughts is by the _choices_ we make of our objects of pursuit. Whatever we choose as our _chief end_, or leading object of desire, becomes the regulator of our emotions, our desires and our thoughts. Thus we have power to control our thoughts aright only by choosing right objects of pursuit. We have power to regulate them in this way, and but very little power to control them in any other. The mere determination to think only on certain subjects in which we feel very little interest avails but for a short time. Speedily the mind returns to its natural course, and brings forward only those objects connected with our chief objects of desire and pursuit. CHAPTER XIV. NATURE OF MIND.—THE MORAL SENSE, OR MORAL SUSCEPTIBILITIES. Those susceptibilities of pleasure and pain which are affected by the conduct of ourselves or others, in reference to rules of _right_ and _wrong_, are called the _moral sense_, or the _moral susceptibilities_. In order to a more clear view of this part of the subject, it is important to inquire as to the manner in which the ideas of _right_ and _wrong_ seem to originate. The young child first notices that certain actions of its own are regarded with smiles and tones of love and approval, while other acts occasion frowns and tones of displeasure.