I think Atheists believe in "a better world."
To explain, Atheists do not believe in any sort of supernatural, higher, or unseen power that governs actions, afterlives, personalities, souls, or other things. They also do not believe that we have our own souls and that frankly, every thought we have, every brain process we have, and every action on earth is based on the laws of physics. Atheists believe that humanity is no different from the animals we all study; in a way, Atheists tend to study other human beings just like human beings study chimps. There's just no supernatural concepts involved; no one would study a chimp and say "Well, that Chimp likes bananas 'cuz God made it that way." or "That monkey's being sinful because it's touching another male monkey." Atheists also do not try to force religious concepts onto factual and proven properties of physics and psychology just because of a lack of understanding of it; an Atheist will simply either say "Oh, I know that because I saw it in a study." or "I don't know anything about that."
However, because people tend to require a belief in something, largely because of upbringing, Atheists tend to be the ones who put their ambitions and drive to real-world solutions and problems; instead of praying for kids in Africa, an Atheist may be the one who puts all the effort to actually raise charity money instead. Or they may take a very critical view and say "Well, the truth is that I have to care about myself before I help anyone else." Atheistic views, like religious views, can be self-centered or can be very optimistic. Generally, views and motivations of any sort come from personal experience and preference, rather than the direct following of an ideology.
