But that very ‘engenders there’ following the ‘shudder in the loins’ puts a heavy damper on the triumph of the member foolhardy. What is begotten there is not precisely suited to welcome the deed of procreation: whoever would like to be the father of ‘the broken wall, the burning roof and tower and Agamemnon dead’? Which of course is a reference to the Trojan war waged on occasion of the unfaithfulness of Helen, one of Leda’s chicks. The fratricide is represented through another pair of chicks: Castor and Polydeukes. Also on da Vinci’s painting the hardly hatched mortals are already attacking each other. And the role of the fourth chick is played by Agamemnon, who was murdered by Helen’s (twin) sister Clytemnestra (in Aeschyles’ version).
In that ‘Agamemnon dead’ resounds still another reproach to the deed of begetting. In ‘Among schoolchildren’ Yeats complains the ‘youthful mother’ ‘honey of generation had betrayed’:
What youthful mother, a shape upon her lap (...)
that must sleep, shriek, struggle to escape (...)
Would think her son, did she but see that shape
With sixty or more winters on its head,
A compensation for the pang of his birth
Or the uncertainty of his setting forth?

What the honey-sweet ‘shudder in the loins’ engenders, is not so much life, rather death. Not to mention all those minor burdens that the poor mortals lift on their shoulders for the lust of one moment’s sake. In the short term the ’pang of birth’. In the somewhat longer term: the care for their progeny ‘that must sleep, shriek, struggle to escape (…)’. And at long last the growing realisation that all these offers have been in vain: we only beget to doom to death. For the sole taste of honey’s sake!
No wonder that love recoils in the face of such dreadful perspective! Yeats, though, never speaks out this truth. He rather prefers to state without any further explanation that love is merely an transient transport – or to phrase it with Schopenhauer: a cunning of nature that is merely out at eternal reproduction. Time and again Yeats stresses the transience of love. In ‘Never give all the heart’ he holds that:
it fades from kiss to kiss;
for everything that’s lovely is,
but a brief, dreamy, kind delight

That is precisely why he warns us ‘Never give all the heart’. With as an encore:
‘He that made this knows all the cost,
for he gave all his heart and lost’

Which of course causes the soul to leave her limbs, as in ‘The lady’s second song’:

Soul must learn a love that is
Proper to my breast,
Limbs a love in common
With every noble beast.

Which again sheds a new light to the swan as ‘the noble beast’
[ next ] intermezzo : the dove