I cannot here follow up further the difficult problem of cognition[78]--save to add one or two supplementary remarks. First: it is, I suppose, fairly obvious that any given field of cognitive relatedness comprises _all_ that is then and there selectively cognized. Just as, in the very extended sense of the word 'knowledge', the earth knows, in gravitative fashion, the whole solar system, as does also any one of the planets, so, in the restricted sense, is knowledge co-extensive with all that is, selectively, in cognitive relationship with the organism or that part of the organism which is the locus of awareness. I speak here of the locus of awareness in just the same sense as I might speak of the earth as a locus of gravitative knowledge of the solar system. The locus of awareness is just a specialized portion of the whole relational web. In other words, the relatedness is of the part-whole kind, where whole means rest of the whole other than the specific part. In any such integrated system the part implies the whole--which, by the way, is quite a different matter from saying that the part includes the whole, or, as I understand the words, is equivalent to the whole. But, whereas gravitative knowledge is reciprocal--the sun knowing the earth in the same fashion as the earth knows the sun--cognitive knowledge is not reciprocal. My cognitive awareness of a spinning-top does not imply that the spinning-top is in like manner aware of me. The part knows the whole in a way that the whole does not know the part. The relationship of the part to the rest of the whole is not reciprocal or symmetrical. This we must just accept as a given feature of cognitive relatedness.[79]