Leave to your opinions their own quiet undisturbed development, which, like all progress, must come from deep within and cannot be pressed or hurried by anything.  Everything is gestation and then bringing forth.  To let each impression and each germ of a feeling come to completion wholly in itself, in the dark, in the inexpressible, the unconscious, beyond the reach of one’s own intelligence, and await with deep humility and patience the birth-hour of a new clarity: that alone is living the artist’s life: in understanding as in creating.*
(Rainer Maria Rilke)

As I think back, no one directly taught me about the critical importance of solitude.

I came to value it through the testimony of people I’d “met” accidentally.  It was on no curriculum I ever experienced.

I only know I must now go there at the beginning and end of the day, that what lies in-between is richer for it.

(*Rainer Maria Rilke, outed in Maria Popova’s Brain Pickings: Rilke on the Lonely patience of Creative Work.)