THE TIME OF ORGANIZED BEINGS l6l 



sideral time flowed four times faster for a man of fifty than for 

 a child of ten. It is evident, on the other hand, that from 

 a psychological point of view many more things happen to a 

 child in a year than to an old man. The year therefore seems 

 much longer to the child, and it is probable that the figures 

 established — the constant A — enable us to reaUze quantita- 

 tively, not only by how much our physiological activity 

 decreases, but also by how much physical time is apparently 

 accelerated in respect to ourselves. 



Thus, we find that when we take physiological time as a 

 unit of comparison, physical time no longer flows uniformly. 

 This affirmation revolts one if the words are taken in a literal 

 sense. But we pointed out in the preceding chapter that if 

 the expression 'flow of time' is in current use, it is nevertheless 

 entirely false and does not correspond to a reality. We have 

 seen that time is inseparable from space and matter and that 

 the four-dimensional continuum, in conformity to the relative 

 concept, is alone capable of furnishing a satisfactory frame for 

 our universe. When, therefore, we say that physical time 

 measured by means of a unit borrowed from our physiological 

 time, no longer flows uniformly, it simply means that it does 

 not seem to flow uniformly. At the bottom of our conscious- 

 ness we perceive a discrepancy between the notion of our 

 external time, without beginning or end, based on our science, 

 our past experience or inherited documents, in other words 

 between the notion of the uniform time of species, and the 

 notion of individual, sensed time, Umited by birth and death, 

 which corresponds to the elementary curves of short period 

 and variable velocity. 



We can separate these two notions by an intellectual effort, 

 but physiological time alone has a reality with respect to us. 

 The envelope curve — the uniform sideral time — is perhaps 

 nothing else but the resultant of the infinity of elementary 

 curves, just as a light wave, or rather the wave front, is the 

 perceptible resultant of the elementary group of waves given 

 out by a luminous source, as shown in Fig. 29. 



The envelope wave expands spherically, and each of its 



