An old adage that applies not just to mechanical creations, but also biological and social systems.
While the cliché may not be true of every system, the best cooperative systems are designed to make that true (or evolved to make that true).
Just imagine if all the cells of your body were split off into individual, independent cells - their ability to adapt the environment to improve their own survival, at that point, drops to next to nothing. (And the same thing often happens to individual humans when they get lost in the wilderness.)
Background
Science Has No Morals
social Darwinism
The evolution of altruism
Darwin's Dangerous Idea
zero-sum game