The dangers of being abandoned when ill—both material and political dangers—explain why sick people are happy to be supported, and why others are eager to provide support. In part, it’s a simple quid pro quo: “I’ll help you this time if you’ll help me when the tables are turned.” But providing support is also an advertisement to third parties: “See how I help my friends when they’re down? If you’re my friend, I’ll do the same for you.”
