Stevens in one of his last poems says he imagines as a kind of final act of nature a bird singing ‘without human meaning, without human feeling, a foreign song.’ The idea that every creature has its own reality scared poets at the beginning of the twentieth century, made some of them feel we were groping blindly---it in effect kicked us out of the comfortable anthropocentric community—but it also allowed some modern poets this sense of absolute mystery at the core of existence. It came of knowing that we would never know exactly what a bird’s experience is, or what an ant’s experience is. It has been an unhousing of the imagination, and it was brought on by the thrust of science to be at home in the world by understanding it. It said we move among great powers and mysteries and only glimpse their meanings, the meaning of what it’s like to be another creature, and therefore also the meaning of being a self, a person.
—Robert Hass, The Poetic Species: A conversation with Edward O. Wilson and Robert Hass (Bellevue Literary Press, New York, 2014, p. 55-56.)