When one speaks of humanity, the idea is fundamental that this is something which separates and distinguishes man from nature. In reality, however, there is no such separation: "natural" qualities and those called truly "human" are inseparably grown together. Man, in his highest and noblest capacities, is wholly nature and embodies its uncanny dual character. Those of his abilities which are terrifying and considered inhuman may even be the fertile soil out of which alone all humanity can grow in impulse, deed, and work.
Friedrich NietzscheThe discipline of suffering, of great suffering- do you not know that only this discipline has created all enhancements of man so far? That tension of the soul in unhappiness which cultivates its strength, its shudders face to face with great ruin, its inventiveness and courage in enduring, preserving, interpreting, and exploiting suffering, and whatever has been granted to it of profundity, secret, mask, spirit, cunning, greatness- was it not granted to it through suffering, through the discipline of great suffering?
Friedrich Nietzsche