A stimulus then must not be conceived as an alien intruder which thrusts itself upon us and, after worming a devious way through our organism as through a piece of cheese, emerges at the other end as an act. Stimuli are only received if they serve some need of the organism and the form which the response to them takes depends only in part upon the nature of the stimulus, and much more upon what the organism ‘wants’, i.e. the state of equilibrium of its multifarious activities. Thus experience has two sources which in different cases have very different importance. So far as we are thinking about or referring to certain definite things our behaviour in all probability will only be appropriate (i.e. our thoughts true) in so far as it is determined by the nature of the present and past stimuli we have received from those things and things like them. So far as we are satisfying our needs and desires a much less strict connection between stimulus and response is sufficient. A baby howls at first in much the same way, whatever the cause of his unrest, and older persons behave not unlike him. Any occasion may be sufficient for taking exercise, or for a quarrel, for falling in love or having a drink. To this partial independence of behaviour (from stimulus) is due the sometimes distressing fact that views, opinions and beliefs vary so much with our differing moods. Such variation shows that the view, belief or opinion is not a purely intellectual product, is not due to thinking in the narrower sense, of response that is governed by stimuli, present or past, but is an attitude adopted to satisfy some desire, temporary or lasting. Thought in the strictest sense varies only with evidence: but attitudes and feelings change for all manner of reasons. The threefold division between the causes, character and consequences of a mental event, conscious or unconscious, corresponds, with certain qualifications, to the usual division in traditional psychology of thought (or cognition), feeling, and will (or conation). To be cognisant of anything, to know it, is to be influenced by it; to desire, to seek, to will anything is to act towards it. In between these two are the conscious accompaniments, if any, of the whole process. These last, the conscious characters of the mental event, include evidently both sensations and feelings. (Cf. Chapter XVL, pp. 125-128.)