Prof. Bain (_Mind_, No. 53) insists that ideas tend to actualise themselves by neutral intensity or excitement, which is feeling; or rather, he says, a “facing-both-ways condition.” This last expression is certainly not very helpful or satisfactory. Prof. Bain admits that typical will is incited by pleasure and pain, but he maintains that sometimes, as notably in imitation, will is stimulated by purely neutral excitement or feeling. In the discussion of this subject much has been said about excitement, and, as Mr. Sully has suggested, this requires careful definition. Reflection assures us that every mental activity has a certain intensity, and the word Excitement may, in the most general sense, denote this intensity. The intensity may be so slight as to be unnoticed by the subject, and remain wholly unindicated to the keenest observer; or it may be so strong as to be perfectly evident to both; or it may be evident to the subject and not to the observer, or _vice versâ_. Thus the obvious division of Excitement from this point of view is into subjective, where it is immediately recognised and felt in the consciousness of the subject, and objective, where it is unnoticed, or noticed only by observer. Classifying by another principle, we may distinguish Cognition-intensity, Feeling-intensity and Will-intensity, and the natural subdivisions under these according to the accepted subdivisions of mental activities. Excitement is not, however, generally used in the large sense we have just mentioned, but as denoting intensity of a high degree so as to be very noticeable to the subject, or observer, or both. It is plain that Excitement, as subjective intensity, is the only kind which bears on the question under discussion. It is with excitement as a feeling, _viz._, the feeling of intensity, and not with excitement as quality of feeling, that is, intensity, that we have to deal, and it is necessary that this distinction be clearly borne in mind. One may be excited but not feel excited, may have intensity of feeling but not feeling of intensity. Using the term, then, as equivalent to feeling of intensity, it is to be noted that it is a reflex or secondary mental state. It is the feeling resulting from consciousness of intensity of consciousness. The intensity of any consciousness may increase to such a point that it pushes itself into consciousness, first as mere recognition of intensity, but immediately and most manifestly as feeling of intensity. In rapid alternations of contrasted states, as of hope and fear, intensity soon rises to such a degree that it forces its way into consciousness as feeling of intensity. This feeling of intensity may be itself either weak or intense. In very reflective natures, the cognition and feeling of intensity may be reflex at any power: there may be cognition of the intensity of cognition-of-intensity, etc., in indefinite regression. Most persons stop with the single step in the regression.