"Nature has done well and wisely, in not permitting a man to live forever and in bringing into the world ever new generations. An old person is a used-up machine [... He] has too many dogmas to [...] easily [...] believe in a new truth [...]; too many sympathies and antipathies [...] for him to come to love something unfamiliar; [...] too many habits to be able to settle on new ways. Let us add suspiciousness — the fruit of bitter experiences; a pessimism inseparable from all manner of disappointments; and finally, a general decline of powers from exhaustion [...]."