UNDER THE APPLE-TREES 



grounds of physical certainty afforded by observa- 

 tion and experience. There are only two kinds of 

 proof, mathematical proof, and experimental or sci- 

 entific proof. There is not, and cannot be, such a 

 thing as metaphysical proof, because metaphysical 

 truths are unconditioned — they are like a sea with- 

 out shores or land without boundaries. We may 

 feel them to be real and true, while another man 

 may not feel them so at all. But the truths of sci- 

 ence and mathematics are true to all men. To dis- 

 pute them is to dispute weights and measures. A 

 path through the fields seems a very real thing: see 

 it winding on ahead of us; our feet can find it in the 

 dark, but it is only a phantom, a negation, an ab- 

 sence of something — a result of the attrition of 

 many feet passing and repassing that way. Where 

 are the tracks we made in last year's snow? The 

 snow was real, and still, in some form, exists; and 

 the feet were real, and may stiU exist; but the track 

 was only a shape in a material thing. 



In the printed page the only real things are the 

 paper and the ink; the white spaces play the same 

 part in aiding the eye to take in the meaning of the 

 print as do the black letters. The type was real, and 

 the mind and hands that shaped the type, and the 

 compositor that set it up, were real, and the sense 

 of the print is real to the mind, but not to the 

 body. All this science affirms ; what does philosophy 

 affirm? 



302 



