"Be admonished: of making many books there is no end; and much study is a weariness of the flesh." ~ Ecclesiastes 12:12
Rudolf Steiner:
As human beings we really live, as it were, throughout the day in a kind of autumn and winter mood. Indeed, the soul's summer mood only exists when the soul is asleep, and the sleeping human body, the physical and the etheric body, is like a plant. And the I and astral body outside shed their rays upon the physical and etheric body like the Sun and the stars, and they call into life again the forces destroyed during the day; vegetable life begins to grow. And the day's thinking activity exists in order to eliminate what the night calls forth as growing life.
When we wake up, we lightly pass over our whole plantlike existence, just like autumn over the plants of the Earth. And when we are awake during the day, we do what winter does to the vegetation of the Earth by destroying in our physical and etheric body the budding, growing life produced at night in the soul's summer time when we are asleep. From this standpoint, it can easily be grasped why people who do not bring at least something of their soul's summer into their waking daytime life dry up so easily. Parched, dried-up little professors are people who do not like to absorb things which are not fully conscious. They do not like to take in anything of the soul's summer seasons. Consequently they dry up; they acquire a pronounced winter character.