The individual is the only real thing in nature and in life. Neither the species, the genus, nor the race, actually exists; they are abstractions, terminologies, scientific devices, useful as syntheses but not entirely exact. By means of these devices we can discuss and compare; they constitute a measure for our minds to use, but have no external reality. Only the individual exists through himself and for himself. I am, I live, is the sole thing a man can affirm.