The title of this great futuristic short story is actually an allusion to a poem bearing the same name by Sara Teasdale. This poem appears as part of the short story and is obviously intimately linked with the theme and message of what Bradbury is trying to say. Perhaps the key quote of the poem is as follows:
And not one will know of the war, not one
Will care at last when it is done.
Not one would mind, neither bird nor tree,
If mankind perished utterly...
The whole poem presents nature carrying on completely as normal without regard for the loss of mankind, which we assume, like in the story, has managed to wipe itself out. Central to the story then is an essential irony: we are presented with a house that displays such levels of technological sophistication that it really doesn't need man at all to keep on going. The scientific level of man is shown to be incredibly high. However, at the same time the absence of any human characters whatsoever forcibly reminds us that man also invented weapons capable of destroying himself. This disparity confronts us with a vital question: what is the point of all of our cleverness if we are unable to realise and accept our vulnerable position in the universe?