NATURE 



lOI 



THURSDAY, APRIL ii, 1918. 



A SURVEY OF EXPERIENCE. 

 Elements of Constructive Philosophy. By Dr. J. S, 



Mackenzie. Pp. 487. (London : G. Allen and 



Unwin, Ltd.; New York: The Macmillan Co., 



n.d.) Price 12s. 6d. net. 

 ;nrHIS is a very pleasant and very instructive 

 J- book. It is like a series of conversations 

 with a thinker of great versatility and great learn- 

 ing, extending over the whole range of logical and 

 metaphysical speculation. Dr. Mackenzie is 

 definite' without dogmatism, and earnest without 

 fanaticism. And he is suggestive on all points 

 that he touches. 



The treatise falls into three parts. The first 

 "book" is devoted to logical discussions; the 

 second to metaphysic — explaining the principal 

 categories by which we conceive of nature and 

 spirit ; the third to what might be called ultimate 

 cosmology, to such problems as the unity and 

 perfection of the universe, the survival of the 

 individual, and the relation of time and 

 eternity. 



In book i., beginning from belief, which the 

 author treats as a mode of selection, and pointing 

 out that the selection cannot be arbitrary, he 

 passes through an account of judgment and of the 

 laws of thought to a first analysis of the control- 

 ling factor, the experience of objective orders. 

 Logic he takes to be the general theory of impli- 

 cation, and all implication — that is, the essence 

 of all inference and judgment and belief — depends 

 upon the recognition of objective orders. To these 

 he devotes a chapter, referring to Driesch's 

 " Ordnungslehre " as the most elaborate treat- 

 ment of the subject, and pointing out that any 

 principle which has some possibility of continuous 

 application may be taken as a principle of order. 

 There are orders of all kinds, from the numerical 

 to the moral order or order of values, and, as 

 M. Bergson has suggested, it is doubtful whether 

 the conception of disorder can mean anything but 

 the absence of some particular order which we 

 chose to expect. In referring to theories of know- 

 ledge, the author well explains that the antithesis 

 of pluralism and cosmism is much more significant 

 than that of realism and idealism, which need not 

 necessarily be an opposition at all. 



In book ii. tha treatment of causation is of 

 interest. In general agreement with Mr. Russell, 

 Dr. Mackenzie holds that it amounts pretty much 

 to the unity of different things as connected by 

 relations that have some regularity. Cause tends 

 to pass into a principle, and effect into a detail. 

 Whether on this ground the distinction between 

 cause and effect can be maintained may seem 

 doubtful. 



An important chapter In this second book is 

 that dealing with valuation. Attempting to arrive 

 at a conception of intrinsic value, the author con- 

 cludes that it must be identified with truth, beauty, 

 XO. 2528, VOL. 101I 



and goodness, and that all else can have value 

 only as instrumental to these. 



From this it is interesting to pass to the con- 

 ception of ultimate reality in book iii., where the 

 problem of reconciling time with the unity of the 

 cosmos (the term universe is applied to units 

 within the cosmos) is attempted on the lines of 

 cycles or histories presenting themselves as dreams 

 which have constancy within an eternal whole, as 

 a play of Shakespeare exists in its own time 

 within the imagination of the poet or reader. 

 The point of the metaphor is that it admits time 

 into the cosmos, but the time so admitted is not 

 a time of the cosmos. And the eternal characters 

 of the cosmos — truth, beauty, goodness — would 

 thus appear in time, without being mere transient 

 events. There is an interesting reference to 

 Oriental sources for such views, and actually a 

 diagram of the upward and downward path. Our 

 fear about all such doctrines is that the paths and 

 cycles may be imagined as divorced from each 

 other and from the characters of the universe. 

 They then become illusions, and the cosmos a 

 " thing-in-itself . " After all, it is in a woman's 

 heart or a nation's spirit that we find what brings 

 us nearest to cosmic reality. 



It is part of Dr. Mackenzie's temperateness 

 that he promises us from philosophy only hope, not 

 conviction. There is truth in this position, so far 

 as particular expectations are concerned. But yet 

 it recalls to us a technical point about the " Laws 

 of Thought." For him they are not based on the 

 nature of reality : you cannot judge at the begin- 

 ning whether reality will prove self-contradictory, 

 but only at the end of your inquiry. This is more 

 difficult than it seems. Unless you start from the 

 coherence of reality, you can never get to it. You 

 cannot separate thought from assertion about 

 reality. If things may be both this way and that, 

 and thought can be only one way, thought is obvi- 

 ously false, and you can make no step towards 

 knowledge. "Make a hypothesis, and test it by 

 facts." But if things being one way does not 

 exclude their being the other way, there are no 

 facts. 



Attention should be directed to Dr. Mackenzie's 

 observations on Mr. Russell and the new realists. 

 His view of Prof. Nunn's theory of external ob- 

 jects seems reasonable. The double pitch of a 

 tone, as heard by a stationary and a receding ear, 

 certainly belongs to it. But neither pitch exists in 

 the absence of the corresponding ear. 



Bernard Bosanquet. 



PRACTICAL ASPECTS OF PRUNING. 

 The Principles and Practice of Pruning. By 

 M. G. Kains. Pp. xxv + 420. (Xew York: 

 Orange Judd Company, 1917.) Price 2 dollars 

 net. 



THE author of this work makes the following 

 statement in his introduction: "Pruning 

 demands a knowledge of plant physiology. Un- 

 less the pruner has a working knowledge of how 



C. 



