Human time is determined by the alternation of day and night. Different forms of day and night can be found everywhere, in all spheres.
Take the seasons. What are spring and summer? They are day: the sun’s influence becomes greater and greater.
And what are autumn and winter? They are night: the moon, symbolically, takes back the power, as nature takes a rest to recuperate, in order for spring and summer to once again produce flowers and fruit.
A month can also be likened to a day: during the fourteen days when the moon is waxing, you could say it is day, and during the fourteen days when it is waning it is night.
Sometimes, even in a single hour, you may have day under the sun’s influence and night under the moon’s, depending on the mood you are in.
But, day or night, there is always mental work to do. Whatever the conditions, there is never any excuse for remaining inactive.