It would seem as if the accomplishment of this task, even in a very tentative and provisional fashion, should be welcomed as a great achievement; but doubtless many philosophers will find that the very statement of the problem involves many metaphysical assumptions. Let that be granted. A man has the right to make such assumptions, and if he does make them, and expressly recognizes that he makes them, and then proceeds to develop the consequences of such assumptions, taken in connection with the findings of fact made by the scientific explorers, he has done a big task if he has done it well. One should not cavil when another chooses to make different assumptions from one's own. For myself, it seems that Professor Whitehead's assumptions are very reasonable; indeed it would be hard to find more sense packed into a little more than twenty pages, than is to be met with in the second chapter, "Theories of the Bifurcation of Nature". Professor Whitehead's treatment of significance also is especially satisfactory. For him the basis of significance is the "disclosure of an entity as a relatum without further specific discrimination of quality. ... Thus significance is relatedness, but it is relatedness with the emphasis on one end only of the relation" (p. 51). According to this view, an "entity merely known as spatially related to some discerned entity is what we mean by the bare idea of 'place'", and the "concept of 'period of time' marks the disclosure in sense-awareness of entities in nature known merely by their temporal relations to discerned entities" (pp. 51-52). This is a logical use of James' 'fringe'.
According to Professor Whitehead's interpretation, "Nature is a process. As in the case of everything directly exhibited in sense-awareness, there can be no explanation of this characteristic of nature. All that can be done is to use language which may speculatively demonstrate it and also to express the relation of this factor in nature to other factors. It is an exhibition of the process of nature that each duration happens and passes. The process of nature can also be termed the passage of nature. ... the measurable time of science and of civilised life merely exhibits some aspects of the more fundamental fact of the passage of nature. ... Also the passage of nature is exhibited equally in spatial transition as well as in temporal transition. It is in virtue of its passage that nature is always moving on" (pp. 53-54). In other words, such concepts as 'space', 'time', 'extension', as used by Whitehead, 'position' in space, 'period of time,' 'continuity', are all abstractions from the fact that nature is moving on.
