Despite this optimism, Americans are less gung-ho about life extension than you’d imagine. A slight majority—51 to 41 percent—say that “if new medical treatments slow the aging process and allow the average person to live decades longer, to at least 120 years old,” this would be “a bad thing for society.” Sixty-eight percent think that “most people would want these medical treatments,” but 56 percent, when asked whether “you, personally, would want” such treatments, say they wouldn’t. The prevailing view seems to be that everybody else wants to live forever, but not me.

Third, believing that death is final doesn’t make you more eager to postpone it. By a margin of 16 percentage points—55 to 39 percent—people who believe in an afterlife say they wouldn’t want treatments to extend their lives to 120. People who don’t believe in an afterlife are more likely to say they wouldn’t want such treatments: 59 to 37 percent, a margin of 22 points.

Why so much resistance? One likely reason is dread about the nature of extended life. Pew’s survey explicitly postulated treatments that “slow the aging process.” But when you’re being asked about living to 120 years or beyond, it’s hard not to picture spending much of that time feeling withered, afflicted, and debilitated. Although the survey didn’t ask about this assumption directly, several findings are consistent with it. For instance…