130 TIME 



travel backwards in it, and no one can boast of being able to 

 regulate its rate of flow. 'It does not cease,' says Sir James 

 Jeans, 'to unfold itself at a uniform and uncontrollable rate 

 which is the same for each one of us.' What is the significance 

 of this difference between space and time? 



It is probably solely due to a misunderstanding, to a faulty 



symbolical representation of relatively clear notions.^ Indeed, 



in effectuating any kind of a displacement, the first condition 



to be fulfilled is to exist; in other words, if a conscious being 



is concerned, to begin to register an evolution through memory. 



The very distance which has to be covered exists only at the 



moment when it is covered — no matter in which way, materially 



or conceptually — and by the very fact that it is covered. It 



may be objected that it suffices to conceive it for it to exist. 



But a moment's reflection shows that there is a gulf between 



a concept and a reality. The proof being that we can easily 



conceive or imagine things which we know to be impossible, 



for instance, the cessation of the flow of time or its inverted 



flow. The important thing for us is reality. It may also be 



objected that to separate two points A and B in space, it 



suffices to see a distance without having to cover it ourselves. 



But our notion of distance between A and B, no matter how 



short it is, implies that it exists in time, and it exists for us 



only from the moment when we have seen it. Hence I take the 



word 'cover' in the very broad sense of perceiving, for the 



simple fact of perceiving two points even simultaneouslyj 



implies that it would take a certain time to go from one to 



another. No distance exists, and naturally no displacement 



can be executed outside of time. We have points of reference 



in space, systems of reference such as the three axes of 



co-ordinates, for instance, thanks to which we know that we 



^ I have already spoken of the fact that we are forced to employ 

 words that have been coined for our current thoughts and daily life. 

 This makes it very difhcult to express relations which we seize 

 intuitively and which we must translate in a language necessarily 

 inadequate. It is certain that a great number of discussions and 

 divergencies of opinion are due to this state of things. It is as if one 

 tried to construct a flower with a puzzle representing a locomotive. 



