The world around us seems to alter, but the change is just an endless circle leading nowhere. It is a rather strong contradiction. He goes on to define this standpoint by stating that we lure our perception into believing that we really see change, when we in fact don't. You see a woman, you think that one day she'll be old, only you don't see her grow old. For Roquentin, change is only in our mind.
Reality never changes.
If time is broken down infinitely into smaller time frames, change would be so small that it appears as if nothing happens. Take a roll of film and let each frame represent an event. If we run the frames fast enough, a string of event will flash before us, which appears to be change. But if we look at each frame individually, all we would see is static events. Another explanation for Roquentin's position could be that we change internally in symbiosis with external objects.