COINCIDENT POSTURES. 151 



cannot give definite criteria by which we may 

 distinguish a voluntary posture from one that is 

 reflex, or the spontaneous outcome of the action 

 of the nerve-centres. We fail, then, to define the 

 adjective "voluntary" as applied to a movement, 

 and this failure is due to our want of knowledge 

 of the criteria of volition. So we shall fail again 

 and again when we try to determine logically 

 the physical criteria of mind. We may accept 

 certain criteria as evidence of mind ; we cannot 

 prove those signs to be evidence of mind. 



Something ought to be said now about the 

 classification and analysis of postures. Now, as 

 postures are nothing but the results of movement, 

 the principles which enable us to analyze and 

 classify movements ought to enable us to analyze 

 and classify postures. It appears needless to repeat 

 those principles verbally, but they may be shown 

 to be applicable to analysis of postures by means 

 of the table in chap, ix., p. 172. 



Coincident postures are often seen in practice, 

 thus : when the left eye is directed outwards, the 

 right eye is directed inwards, and vice versa. Sym- 

 metry of posture is a division of coincident postures. 

 Certain postures of the head and the hand so com- 

 monly coincide as to give special expression. In a 

 weakly child we often see the left hand in the 

 nervous posture, and the head in slight right rotation 

 with right inclination and flexion. In that physical 

 condition where the mental state is called " horror " 

 at the sight of an object, the upper extremities 

 extend towards the object, the eyes and head 



