Contractualism

Contractualism is an idea in philosophy. It is part of moral philosophy, which is ideas about right and wrong.
There are two ways to think of contractualism: broad (general) and narrow (specific). Broadly, contractualism is the idea that morality comes from agreements between people. Keeping your promises is good and breaking them is bad. Narrowly, contractualism is a set of ideas from Harvard philosopher T.M. Scanlon. Scanlon wrote an essay, "What We Owe to Each Other."
Scanlon's essay says that the act of reasoning whether an action is good or bad (good thinking) is just as important as figuring out whether it is good or bad. That is, asking the right question in the right way is just as important as finding the answer. Scanlon's contractualism says that an action is morally bad if it "cannot" be explained as good to another human being.
Like many other philosophies, contractualism says that all human beings are equally important. It is different from other philosophies in "why" human beings are equally important. Contrctualism says human beings are equally important because they can reason and think. For example, utilitarianism says human beings are equally important because they can all feel good or bad.
In popular culture.
Scanlon's philosophies are in the television show "The Good Place". The show's writers say that Scanlon's philosophiles inspired parts of the show's main story. The characters read and talk about Scanlon's book on the show.