On all other accounts the relation between an awareness and what it is aware of is a mystery. We can name the relation as we please, apprehension, presentation, cognition or knowledge, but there we have to leave the matter. On this account we make use of the fact that an awareness, say of a variety of black marks on this page, is caused in a certain peculiar way, namely through impressions on a part of the brain (the retina) and various complicated connected goings on in other parts of the brain. To say that the mental (neural) event so caused is aware of the black marks is to say that it is caused by them, and here ‘aware of’ = ‘caused by’. The two statements are merely alternative formulations. In extending this account to more complicated situations where we know or, less ambiguously, _refer to_ things which are past or future we have to make use of the fact that impressions are commonly _signs_, have effects which depend not on themselves alone but upon the other impressions which have co-operated with them in the past. A sign[40] is something which has once been a member of a context or configuration that worked in the mind as a whole. When it reappears its effects are as though the rest of the context were present. In analysing complex events of referring we have to break them up artificially into the simpler sign-situations out of which they arise; not forgetting meanwhile how interdependent the parts of any interpretation of a complex sign are. The detail of this procedure is most easily studied in connection with the use of words. We shall deal with it therefore in Chapter XVI, where the reading of a poem is discussed. Here only the general principle matters that to know anything is to be influenced by it, directly when we sense it, indirectly when the effects of past conjunctions of impressions come into play. More will be added later, in connection with the process of reading, about the receptive, the knowledge aspect of mental events. The other two aspects need less explanation. They are also more generally important for the understanding of poetic, musical and other experiences. For a theory of knowledge is needed only at one point, the point at which we wish to decide whether a poem, for example, is true, or reveals reality, and if so in what sense; admittedly a very important question. Whereas a theory of feeling, of emotion, of attitudes and desires, of the affective-volitional aspect of mental activity, is required at all points of our analysis. [34] _Eyeless Sight_, p. 22. [35] _Dedalus, or Science and the Future_, by J. B. S. Haldane. [36] Compare Chapter XXXIV where the ways in which emotive factors interfere with thought are considered. [37] Cf. Piéron, _Thought and the Brain_, Chapter I. [38] Many apparent questions which begin with the words ‘What’ and ‘Why’ are not questions at all, but requests for emotive Satisfaction.