E.M.Forster, Aspects of the Novel:
"When human beings love they try to get something. They also try to give something, and this double aim makes love more complicated than food or sleep. It is selfish and altruistic at the same time, and no amount of specialization in one direction quite atrophies the other. How much time does love take? This question sounds gross but it bears on our present inquiry. Sleep takes about eight hours out of twenty-our, food about two more. Shall we put down love for another two?"