"Psychology which explains everything / explains nothing, / and we are still in doubt."
This line is one of many that expresses Moore's attempt to reconcile how otherwise smart and progressive and thoughtful and independent people (particularly Bryher Ellerman, the friend whose marriage most likely impelled Moore to write this poem) could enter into a union that is so fraught with potential for strife and failure. She points out the irony here that psychology, a discipline which has claimed the ultimate mantle of authority in explaining why people do what they do, is utterly unequipped to answer this question. If psychologists cannot do this, then who can? It is only through Moore's collaging together of various quotes and sources rather than relying on experts and "authorities" that we can actually get to some of the essence of marriage.
"Adam; / 'something feline, / something colubrine'—how true!"
These lines are from a review of the poetry of George Santayana and are used to discuss Adam. Both "feline," which is a traditionally more feminine label, and "colubrine," which means "snake-like," are curious terms to describe this ur-male. "Feline" suggests he is actually more feminine than masculine, and connotes slinkiness. "Colubrine" may have phallic connotations, but it also suggests a more predatory, dangerous nature. This is borne out in the way that Adam asserts his will and tries to control Eve. Finally, it is an interesting word to use for Adam as opposed to Eve because the woman and the serpent are traditionally viewed as more intertwined given Eve's temptation in the garden; here, though, Moore refuses to let Adam off the hook (no "exonerating" here) and associates him with the snake.
"the ease of the philosopher / unfathered by a woman"
This is a fascinating little line that doesn't often see much critical analysis. It is worth pausing on it and realizing that yes, Adam was not born of, nor nurtured or raised by, a mother/woman. He is ALL man, created by a male God and given dominion over the earth and all its creatures. Moore seems to say that it is no wonder, then, that he tries to dominate Eve and is annoyed when she does not sing like the nightingale for him. It is no wonder, then, that men in general have power and want to make people feel it.
"from forty-five to seventy / is the best age"
This phrase is from lines of Anthony Trollope's novel Barchester Tower, and is used here as part of the image of Hercules grasping for the apples; looking even more broadly it is Moore moving on from discussing the particulars of Adam and Eve and their love to a general critique of marriage. The age range is a strange one -these are not the years most people when people get married, and they do not seem the most sensual, passionate years. Moore had told her friend and fellow poet H.D. in a letter that she doubts if there is anything like a "love affair in the case of people under 40." Critics Keller and Miller note, "Such timing is belated by the standards of modem expectation, but in the poem's terms it does provide for the real existence of 'love that will I gaze an eagle blind,' love as heroic as that of Hercules 'in the garden of the Hesperides.' Yet even this fragile possibility of love for those over forty-five wanes as the sentence returns to mockery: the male speaker flippantly commends love as anything from 'a fine art' to 'a duty . . . or merely recreation.'"
"the spiked hand / that has affection for one / and proves it to the bone"
This is an excellent metaphor for how the affection that putatively exists in marriage can actually be quite harmful and oppressive. A "spiked hand" conjures something medieval, something more apt to torture than titillate. The visceral, violent image of it getting "to the bone" furthers the sense that this is not a soft, loving touch. The line continues in a doth-protesteth-too-much fashion, stating that the hand is "impatient to assure you / that impatience is the mark of independence, / not of bondage." Talking in an impatient way, which is negative, in order to try and emphasize the positivity of impatience does not make sense, and it makes even less sense that a spiked hand could be anything other than bondage. This is just one of the many examples of legerdemain and rationalization that take place between people trying to convince others, and themselves, that marriage works.