Let us sum up briefly. For a common-sense time, which can always be converted into psychological duration and which thus happens to be real by definition, the theory of relativity substitutes a time that can be converted into psychological duration only in the case of the system's immobility.
This is Bergson's judgment from the standpoint of his own duration philosophy. His critique of relativity as such has multiple tines if you will. The logical one is the twins paradox which Einstein himself regarded as a quirk. The twin on earth sees the twin in the rocket as aging more slowly, however by the prime tenet of special relativity one can regard the rocket as immobile and the earth as moving away from it at near the speed of light. Thus the twin in the rocket will see the twin on earth as aging more slowly. This inconsistency (principle of non-contradiction) would normally be seen as a reductio ad absurdum. 'Hold on' the philosopher is inclined to say 'before you go on the return journey from the star and initiate another inertial frame please sort out that contradiction'. In my persusal of various videos while the contradiction is mentioned nobody really engages with it. They are too pleased to be able to present the brother returning to earth in his own distant future.
It is the outward bound initial contradiction that I find to be the real paradox.
Now if the brothers were in rockets passing each other then both would ‘see’ the other as ageing more slowly and they would both be right as their own situation would seem normal to them from their own perspective.