Ray Bradbury has created a rare storyline that includes no human beings or human interaction. Earth's humans have created a weapon that destroys all human life, leaving only a building which is unable to be demolished. Inside, the house continues to function efficiently despite the lack of people to enjoy its mechanical marvels. One of the themes explored is that of Man vs. Machine. By creating a technological device that can destroy all humanity, man is seen as a creature who believes himself both superior and clueless to the possible repercussions. Yes, machines can replace humans, functioning in their place (as seen by the house); however, there is no life or love or interaction. Without humanity, the function of machines is meaningless.
Another theme explored by Bradbury is that of Science vs. Nature. Although it appears that science has destroyed humanity, the earth still survives. The house, impregnable to destruction and able to maintain itself, is nevertheless accidentally destroyed by fire--an act of nature.