A bunch of stupid things get together and do smart things. This seems impossible, but you are familiar with the phrase "the whole is more than the sum of its parts." An ant is only a bug, but a bunch of ants together build towers and colonies. Your brain is made up of cells that don't have much value alone, but together they make a brain that can think.
A video from Kurzgesagt looks at how many systems work this way. It's a bit mind blowing, thinking about how atoms, cells, ant colonies, and human societies all display emergence -they are complicated systems made up of simple parts. -via Kottke