Revealed Preference of saving lives

From Steven E. Landsburg, More Sex is Safer Sex: The Unconventional Wisdom of Economics, p. 220.

If putting a dollar value on human lives strikes you as cold-hearted, grow up. You implicitly put a dollar value on human lives every time you buy a candy bar with funds that could instead have been donated to the local fire department. No matter who you are, there is a limit to what you’re willing to spend to save lives; the only question is whether you’re willing to think honestly about what that limit is.