History was the controlling trope for 19th-century writers: Novelists, essayists, poets, and playwrights all affirmed their hopes for mankind's progress, or their fears about the decline and fall of civilization, by pointing to the record. The discoveries of Darwin and Einstein seem, at first glance, to have shifted our metaphor to science. Even Biblical fundamentalists who reject evolutionary theory will often subscribe to "Social Darwinian" demonstrations of survival of the fittest in the marketplace. Though physics may be too technical for a mass audience, "relativity" has revolutionized moral attitudes. But literature still frequently shrinks from science. Old-fashioned narratives continue to treat time as if it operated like a piece of thread unwinding from a spool, and man as if he were a unique phenomenon of nature. In The Past Galway Kinnell reports a dinner table discussion on this problem with Richard Hugo shortly before his death:

Although Kinnell has not invented an evolutionary mode of speech, his poems certainly exemplify a way of thinking that has embraced a biological perception of the world. Much of The Past was inspired by personal changes in his life: divorce, children growing up, the death of friends. Yet his consideration of these losses forms around his conviction that man is part of the animal kingdom, and must be stripped "back down / to hair, flesh, blood, bone, the base metals," to be seen for what he is.

Kinnell is a descendant of Rilke, the poet who first suggested that the material world may be superior to the heavenly one. In "The Olive Wood Fire," Kinnell borrows his mentor's sense that God no longer watches over the world by describing how he used to rock his son, Fergus, before the fireplace when the boy had awakened from nightmares. The flames remind the father of the horrors of the Vietnam war as seen on television:

One such time, fallen half-asleep myself,
I thought I heard a scream
—a flier crying out in horror
as he dropped fire on he didn 't know what or whom,
or else a child thus set aflame—
and sat up alert. The olive wood fire
had burned low. In my arms lay Fergus,
fast asleep, left cheek glowing, God.

This vision of a childlike deity who sleeps through human horrors manages to combine Christian iconography with 20th-century agnosticism.

Speaking both of history and of his own youth, Kinnell recalls that "back then, dryads lived in these oaks; / these rocks were altars, which often asked / blood offerings." This personification of nature remains dear to many contemporary poets, who see themselves as shamans. Kinnell has abjured it, however. In "The Seekonk Woods," his image for a kind of afterlife becomes the stink of a muskrat-skin cap that cannot lose the scent of its dead animal. A lucky person can, like James Wright, feel kinship with "salamanders, spiders and mosquitoes," and so imaginatively pick up "back evolutionary stages"—rather like dropped stitches in knitting, evidently. In "The Waking," lovers during the act imagine that they are demi-gods lost in an arcadian landscape, but must come to "and remember they are bones and at once laugh/naturally again."

The irony of Darwin's title, The Descent of Man, was not lost on the language-conscious Victorians, who felt that in this new perspective they had suffered a fall from the hope of Divine ordinance, especially an eternal life of which the earthly one was merely a shadow. The Past is an attempt to reconcile oneself to the fact that one cannot re-enter times that are gone. "I have always intended to live forever, / but even more, to live now. The moment/I have done one or the other, I here swear, / I will come back from the living and enter/death everlasting: consciousness defeated." In Kinnell's post-Darwinian world, truth means facing the knowledge that our lifecycle consists of no more or less than growth, propagation and decay, and that we fulfill our function by living it:

The rails may never meet, O Fellow Euclideans,
for you, for me. So what if we groan?
That's our noise. Laughter is our stuttering
in a language we can 't speak yet. Behind,
the world made of wishes grows dark. Ahead,
if not tomorrow then never, shines only what is….