Carl Jung on the thirty-fifth year when things begin to change.
Modern Psychology: C. G. Jung’s Lectures at the ETH Zürich, 1933-1941
A point exists at about the thirty-fifth year when things begin to change, it is the first moment of the shadow side of life, of the going down to death.
It is clear that Dante found this point and those who have read Zarathustra will know that Nietzsche also discovered it.
When this turning point comes people meet it in several ways: some turn away from it; others plunge into it; and something important happens to yet others from the outside.
If we do not see a thing Fate does it to us. ~Carl Jung, ETH Lectures, Page 233.
