Answer: You cannot assess your advancement properly since you don’t have any means of measuring it. Until you’ve reached the spiritual world, you are unable to fathom what is in your possession, just as a child cannot differentiate between playing with toys and reality.
Similarly, an adult who works in a big company, a science lab, or a vast social system, who considers himself big, important, and involved in serious work doesn’t sense that he lives on a tiny planet near the border of a small galaxy, lost in the universe. Everyone feels his place in accordance with his degree.
But how do we receive a portion of the Light so that we can measure ourselves against it at our degree? It doesn’t have to be a complete assessment relative to our final, fully corrected state (this cannot be done until the end of correction), but we will gradually move toward it along the “right” and “left” lines. And we will use the “right” and “left” impressions to correctly balance ourselves along the “middle line.”
From the 1st part of the DailyKabbalah Lesson 4/28/2011, Writings of Rabash