FORCING INTELLIGENCE 79 



gence, and thus have the physical disadvantages 

 under which our ancestors labored become the fac- 

 tors by which their intelligence was pushed forward. 

 Let the reader bear in mind that this complexity of 

 organism is an inseparable concomitant of the 

 upright attitude, and a condition precedent on 

 which the possibility of this posture depends. 



The sense of touch is the only means by which 

 creatures may become intimately acquainted with 

 the qualities or attributes of things. 



By touch we become aware of size, form, hardness, 

 softness, roughness, smoothness, rest or motion, 

 sharpness, dullness, hollo wness, solidity. Of these 

 attributes of things none of the other senses can 

 directly inform, but certain impressions on them are 

 invariably connected with experiences of touch 

 which yield direct knowledge of these qualities. 

 Because of this invariable connection, our minds 

 automatically infer these qualities from actions on 

 the other senses, even when the direct evidence 

 from the sense of touch is absent. It may seem as 

 if hollowness and solidity could be distinguished by 

 sound, but if touch had not taught their nature 

 beforehand the respective sounds never could. 

 Touch, even here, supplies the primary experience 

 and familiarity. 



By sight we can only distinguish lights, shadows, 

 and colors. The extremely diminutive areas of 

 lights, shadows, colors, marked off on the retina by 

 changes in external things and conditions, cannot 



