xiv.] ON DESCARTES &quot; DISCOURSE.&quot; 283 



go on digging and delving until he came to the solid adamant ; 

 or, at worst, made sure there was no adamant. As the record of 

 his progress tells us, he was obliged to confess that life is full of 

 delusions ; that authority may err ; that testimony may be false 

 or mistaken ; that reason lands us in endless fallacies ; that 

 memory is often as little trustworthy as hope ; that the evidence 

 of the very senses may be misunderstood ; that dreams are real 

 as long as they last, and that what we call reality may be a long 

 and restless dream. Nay, it is conceivable that some powerful 

 and malicious being may find his pleasure in deluding us, and 

 in making us believe the thing which is not, every moment of 

 our lives. What, then, is certain ? What even, if such a being 

 exists, is beyond the reach of his powers of delusion ? Why, 

 the fact that the thought, the present consciousness, exists. Our 

 thoughts may be delusive, but they cannot be fictitious. As 

 thoughts, they are real and existent, and the cleverest deceiver 

 cannot make them otherwise. 



Thus, thought is existence. More than that, so far as we are 

 concerned, existence is thought, all our conceptions of existence 

 being some kind or other of thought. Do not for a moment 

 suppose that these are mere paradoxes or subtleties. A little 

 reflection upon the commonest facts proves them to be irrefrag 

 able truths. For example, I take up a marble, and I find it to 

 be a red, round, hard, single body. We call the redness, the 

 roundness, the hardness, and the singleness, &quot; qualities &quot; of the 

 marble ; and it sounds, at first, the height of absurdity to say 

 that all these qualities are modes of our own consciousness, 

 which cannot even be conceived to exist in the marble. But 

 consider the redness, to begin with. How does the sensation of 

 redness arise ? The waves of a certain very attenuated matter, 

 the particles of which are vibrating with vast rapidity, but with 

 very different velocities, strike upon the marble, and those which 

 vibrate with one particular velocity are thrown off from its 

 surface in all directions. The optical apparatus of the eye 

 gathers some of these together, and gives them such a course 

 that they impinge upon the surface of the retina, which is a 



