We're alive to every nuance in our partner's behaviour toward us; we notice and are pained by every piece of distance, every moment of incomprehension and every minor slight.
Was this life? A fleeting thing without meaning? It was only life that pained. There was no hurt in death. To die was to sleep. It meant rest. Then why was he not content to die?
In their own lives and observations they also saw the cruelty of science and the bleaker aspects of inheritance: the madness, the sorrow, the chained ape's pained, silent gaze.
But immediately, noticing the pained expression his joke had brought to his sister's face, he repented and added: " I am glad; really, dear, I am very glad."