174 DESCARTES' DISCOURSE u\ METHOD TV 



green ; and he would be quite as right in saying 

 that it is green, as we are in declaring it to be 

 red. But then, as the marble cannot, in itself, 

 be both green and red, at the same time, this 

 shows that the quality " redness " must be in our 

 consciousness and not in the marble. 



In like manner, it is easy to see that the round- 

 ness and the hardness are forms of our conscious- 

 ness, belonging to the groups which we call 

 sensations of sight and touch. If the surface of 

 the cornea were cylindrical, we should have a 

 very different notion of a round body from that 

 which we possess now; and if the strength 

 of the fabric, and the force of the muscles, of the 

 body were increased a hundredfold, our marble 

 would seem to be as soft as a pellet of bread 

 crumbs. 



Not only is it obvious that all these qualities 

 are in us, but, if you will make the attempt, you 

 will find it quite impossible to conceive of " blue- 

 ness," " roundness," and " hardness " as existing 

 without reference to some such consciousness as our 

 own. It may seem strange to say that even the 

 " singleness " of the marble is relative to us ; but 

 extremely simple experiments will show that 

 such is veritably the case, and that our two 

 most trustworthy senses may be made to contra- 

 dict one another on this very point. Hold tlie 

 marble between the finger and thumb, and look 

 at it in the ordinary way. Sight and touch agree 



