174 TIME 



We have now come to the end of this study, which has led 

 us from the biological problem in general to the notion of 

 time. The first part of this book can be compared to a trip in 

 an aeroplane at a low altitude above a poorly explored country 

 of varying aspects. From on high, without going through the 

 fatigues and deceptions of the explorer, we have been able to 

 realize the enormous and various difficulties which he would 

 encounter on his way. Then, choosing with care our landing- 

 place, we alighted in a region more easy of access than the 

 others, though still barren. We then reported in detail the 

 material labour of the pioneer, the clearing of the land, the 

 organization of the conquered ground, the tracing of roads 

 leading to already colonized regions, the blazing of trails 

 towards the unknown. Once this programme accomplished, 

 we again stepped into the aeroplane and rose to a greater 

 height, losing sight of the details but embracing in a single 

 sweep of the eye our universe and the relations between 

 certain external causes and their subjective effects. Chance 

 decreed that some of our experiments were of a nature to 

 throw a little light on the fundamental notions which form the 

 frame of our concepts. We deducted therefrom a few con- 

 clusions which seemed to us legitimate. We do not doubt 

 that we will be criticized for it. And yet, is it not logical to 

 try to throw a bridge between the external world and our 

 consciousness, considering that we can now approach the 

 problems which have preoccupied men for centuries: problems 

 of space, of matter, of time? The pure physicist cannot do 

 this for, a priori^ he neglects consciousness, which is not of his 

 domain. Progress in this direction can therefore come only by 

 the path of biology. 



The purely imaginary, philosophical concepts of olden days 

 are outdistanced. Our ideas on matter are infinitely more 

 mysterious than the wildest lucubrations of philosophers. We 

 cannot, and will not, doubt the evidence of our senses, the 

 indications of our instruments, and the deductions of our 

 intelligence. We admit that the properties of things are due 

 to the motion of elements which seem to have no existence 



