THE PERCEPTION OF SPACE. 149 



terminations can be effected except tlirougli an act of re- 

 lating thought, so that your attempt to give an account of 

 space in terms of pure sensibility breaks down almost at 

 the very outset. Position, for example, can never be a sen- 

 sation, for it has nothing intrinsic about it ; it can only 

 obtain hetiveen a spot, line, or other figure and extraneous 

 co-ordinates, and can never be an element of the sensible 

 datum, the line or the spot, in itself. Let us then confess 

 that Thought alone can unlock the riddle of space, and 

 that Thought is an adorable but unfathomable mystery." 



Such a method of dealing with the problem has the 

 merit of shortness. Let us, however, be in no such hurry, 

 but see whether we cannot get a little deeper by patiently 

 considering what these space-relations are. 



'Relation' is a very slippery word. It has so many 

 different concrete meanings that the use of it as an abstract 

 universal may easily introduce bewilderment into our 

 thought. We must therefore be careful to avoid ambiguity 

 by making sure, wherever we have to employ it, what its 

 precise meaning is in that particular sphere of application. 

 At present we have to do with space-relations, and no others. 

 Most ' relations ' are feelings of an entirely different order 

 from the terms they relate. The relation of similarity, e.g., 

 may equally obtain between jasmine and tuberose, or be- 

 tween Mr. Browning's verses and Mr. Story's ; it is itself 

 neither odorous nor poetical, and those may well be pardoned 

 who have denied to it all sensational content whatever. 

 But just as, in the field of quantity, the relation between 

 two numbers is another number, so in the field of space the 

 relations are facts of the same order with the facts they relate. 

 If these latter he patches in the circle of vision, the former 

 are certain other patches betiveen them. When we speak of 

 the relation of direction of two points toward each other, 

 we mean simply the sensation of the line that joins the two 

 points together. The line is the relation; feel it and you 

 feel the relation, see it and you see the relation ; nor can 

 you in any conceivable way think the latter except by im- 

 agining the former (however vaguely), or describe or indi- 

 cate the one except by pointing to the other. And the 

 moment you have imagined the line, the relation stands 



