Answer: We advance in the form of turning wheels: some of the wheels go forward, and another moves backwards. Some of them move from bottom to top, some move from top to bottom. The wheel advances forward, and its parts execute various actions.
If a person measures himself in relation to a goal, then he understands that he progresses. But if he measures himself only in relation to ascents and descents or in relation to other states, then it sometimes seems to him as if he is moving backward or standing still.
There are many possibilities to measure the advancement. But the most definite examination is: Do you feel today, as compared to yesterday, a greater necessity to find connection with group? That is the surest examination.
From the 2nd part of the Daily Kabbalah Lesson 2/13/12, The Zohar