August 26, 1920] 



NATURE 



799 



we have dualism, a dualism which he gets over 

 by referring the origin of the activity of mind 

 and the object with which it is compresent, alike, 

 to a final reality which is the foundation of both, 

 an ultimate space-time continuum. This, inas- 

 much as the flow of time enters into its very 

 essence, is not static, but dynamic. The activity 

 which we are conscious of (in the form, not of 

 perception, which is of objects, but of self-enjoy- 

 ment) is therefore in its turn dynamic, and its 

 character is that of a conation. 



I am not sure that the Americans, notwith- 

 standing their boldness, are not here on safer 

 ground. They project everything, thought, feel- 

 ing, and tertiary qualities, such as goodness and 

 beauty, into what they call a non-mental world. 

 Prof. Alexander is more cautious. With him the 

 native hue of resolution is, at times at least, as 

 he progresses in his enterprise, sicklied o'er with 

 the pale cast of thought. He seems to feel that 

 he must retain something for a mental world. 

 Starting with space and time as having no reality 

 apart from one another, but as mere abstractions 

 from aspects or attributes of the foundational 

 reality, which is space-time or motion, the "stuff 

 of which all existents are composed," he has to 

 account for our actual experience. His founda- 

 tionally existent activity breaks itself up into the 

 complexes of which we are aware, and which 

 possess, as belonging to their nature, certain 

 fundamental and all-pervasive features which we 

 recognise as categories. There result also quali- 

 ties which appear in our experience. These form 



" a hierarchy, the quality of each level of existence 

 being identical with a certain complexity or col- 

 location of elements on the next lower level. The 

 quality performs to its equivalent lower existence 

 the office which mind performs to its neural basis. 

 Mind and body do but exemplify, therefore, a rela- 

 tion which holds universally. Accordingly, time 

 is the mind of space, and any quality the mind of 

 its body ; or, to speak more accurately, mind and 

 any other quality are the different distinctive com- 

 plexities of time which exist as qualities. As 

 existents within space-time, minds enter into rela- 

 tions of a perfectly general character with other 

 things and with one another. These account for 

 the familiar features of mental life ; knowing free- 

 dom, values, and the like. In the hierarchy of 

 qualities the next higher quality to the highest 

 attained is deity. God is the whole universe 

 engaged in process towards the emergence of this 

 new quality, and religion is the sentiment in us 

 that we are drawn towards him, and caught in 

 the movement of the world towards a higher level 

 of existence." 



I have given the general result of his inquiry 

 as summed up in the author's own words, those 

 NO. 2652, VOL. 105] 



used by him in concluding his final chapter. But 

 it would be unfair to suggest that the nature of 

 this result can be appreciated from any isolated 

 quotation. The whole book must be read. It is 

 admirable alike in thoroughness of method and in 

 command of material. Still, it is obvious that the 

 entire edifice depends for its stability on its 

 foundation, and that the author's conception of the 

 ultimately real as being space-time, a continuum 

 of point-instants or pure events entirely inde- 

 pendent of mind, is the crucial point in his reason- 

 ing. If he is right, it must be in terms of this 

 existent that all else must be capable of expres- 

 sion, and it cannot itself be expressed in terms of 

 anything beyond itself. Of course. Prof. Alex- 

 ander does not dispute that when we speak of 

 space and time as of this character we are going 

 beyond what we learn through sense, or in- 

 tuitively, and are employing constructions of re- 

 flection. He is quite entitled to do this if a non- 

 mental world can include universals, as he insists, 

 in common with all New Realists. Our simplest 

 experience is, as he says, "full of our ideas." The 

 question is whether they belong to mind or to what 

 is not mind. We shall see presently to what path 

 this conclusion conducts. 



At this stage we have to put before us the 

 author's analysis of the relation of space to time, 

 an analysis that seems to me altogether admirable. 

 Space taken in abstraction from time has no dis- 

 tinction of parts. Time in so far as it is purely 

 temporal is a mere now. To find a continuum we 

 must find distinguishable elements. Without 

 space there would be no connection in time. 

 Without time there would be no points to connect. 

 There is therefore no instant of time apart from 

 a position in space, and no point of space except 

 in an instant of time. The point occurs at an 

 instant, and the instant occupies a point. The 

 ultimate stuff of the universe is thus of the char- 

 acter of point-instants or pure events, and it is 

 so that we get our continuum. The correspond- 

 ence is, however, not a one-to-one, but a many- 

 one, correspondence. For one point may occur 

 at more than one instant, and one instant may, 

 analogously, occupy several points. 



Prof. Alexander thinks that he is here in full 

 accord with Minkowski's well-known conception 

 of an absolute world of four dimensions, of which 

 ordinary geometry omits the fourth, the time 

 element. When he wrote his book Einstein's 

 doctrine of relativity was only fully known in its 

 first form, the "special" theory, and Prof. Alex- 

 ander believes that his view of the character of the 

 space-time continuum has left him free to accept 

 the so-called principle of relativity in this form. 



