Answer: It seems to us as if this is a very long period of time. The universe and inanimate, vegetative, and animate nature developed precisely in order to clarify the difference between light and darkness.
This took place initially at the lowest, inanimate level, in atoms and molecules, etc. Then, it continued on the vegetative and animate levels, in various biological and zoological components of nature. Afterward, it took place on the human level of our world, not only in physiology, but also in human psychology.
Only after that can a person come closer to being worthy of starting research on a spiritual level.
From the Kabbalah Lesson in Russian 12/10/17