Duration, Detente, Extension

One prominent attempt to explain the origin of Extension, i. e. to not accept it as merely given, is Bergson's, which is based on his theory of the relation between Spirit and Matter.  He conceives Matter to be a spreading out of Spirit, via a process of relaxation, leading towards inertia, in which 'extension' gradually emerges in its later stages.  However, the French for that process is actually the sibling 'detente'.  Furthermore, Bergson does not consider the possible relevance of the common use of 'extend' to his concept of Duration, which can be conceived as a constant extending beyond a current moment, i. e. he does not consider that Extension can be appreciated to be a Spiritual process.  Instead, even as he bridges Cartesian Dualism, he misses the linguistic clue that the gerund 'extension' is the product of the participle 'extension'.