RELATIONS BETWEEN MIND AND MATTER. 85 



and there is justification for even this doubt. Have not the 

 mathematicians lately told us emphatically that there are no 

 axioms, that all once held as absolutely true about lines and 

 angles — in short, geometry — has no better basis than experi- 

 ment and the narrow limits of our experience, thus bringing our 

 rational powers to a standstill in the presence of problems out 

 of the range of our instrurpents ? This is precisely what has 

 been done, and for all we know the universe may be a very 

 different thing from what it has seemed to be, for in concluding 

 what it is we have always assumed that space was what it 

 seemed to be, and that ideally one could go in a straight line 

 on and on forever. Now we do not know that, say the mathe- 

 maticians ; and they talk of space of four or more dimensions 

 where our laws of physics and energy will not hold. And 

 more than that, some of them begin to derive comfort from 

 the reflection that, after all, the universe is not half so simple 

 and easy to understand as they had once thought, and that the 

 possibilities of knowledge and of existence may vastly exceed 

 anything any one has yet imagined. For us, then, science 

 must be correlated experie^ices, and for us the truth can only be 

 that statement which is in accordance with the best and most 

 certain other things we know ; it must be in accordance with 

 our geometry, our energy, with our modes of thought, and then 

 always with the reservation that what to-day seems funda- 

 mental may ultimately turn out to be derived, and relations 

 that seem obvious may be far from it. 



All this is a sort of disclaimer against being taken for 

 one who believes and teaches that the knowledge we have 

 is sufficient to enable him or others to deduce all phenom- 

 ena, or even to foresee in any kind of way how to answer 

 properly many of the questions which concern us all. The 

 decalogue was mostly a compendium of donts, and the best 

 that such science as I have knowledge of can now do is 

 to tell us what not to do, rather than what at once to do, 

 and sives a mere hint as to the direction one must look for 

 further light on any or all of them. Of course we all know 

 how men have speculated on both mind and body and their 

 relation, and it has always bejn quite the fashion to go into 



