Philosopher Joshua Knobe recently posed a perplexing question in contemplating the nature of the self: If the person you will be in 30 years — the person for whom you plan your life now by working toward career goals and putting money aside in retirements plans — is invariably different from the person you are today, what makes that future person “you”? What makes them worthy of your present self’s sacrifices and considerations? That’s precisely what Harvard psychologist Daniel Gilbert explores in this short and pause-giving TED talk on the psychology of your future self and how to avoid the mistakes you’re likely to make in trying to satisfy that future self with your present choices. Picking up from his now-classic 2006 book Stumbling on Happiness (public library), Gilbert argues that we’re bedeviled by a “fundamental misconception about the power of time” and a dangerous misconception known as “the end of history illusion” — at any point along our personal journey, we tend to believe that who we are at that moment is the final destination of our becoming. Which, of course, is not only wrong but a source of much of our unhappiness.

Human beings are works in progress that mistakenly think they’re finished. The person you are right now is as transient, as fleeting and as temporary as all the people you’ve ever been. The one constant in our lives is change.

Gilbert explores this paradox in greater, pleasantly uncomfortable-making, strangely reassuring detail in Stumbling on Happiness — one of these essential books on the art-science of happiness. He writes:

What would you do right now if you learned that you were going to die in ten minutes? Would you race upstairs and light that Marlboro you’ve been hiding in your sock drawer since the Ford administration? Would you waltz into your boss’s office and present him with a detailed description of his personal defects? Would you drive out to that steakhouse near the new mall and order a T-bone, medium rare, with an extra side of the really bad cholesterol? The things we do when we expect our lives to continue are naturally and properly different than the things we might do if we expected them to end abruptly. We go easy on the lard and tobacco, smile dutifully at yet another of our supervisor’s witless jokes, read books like this one when we could be wearing paper hats and eating pistachio macaroons in the bathtub, and we do each of these things in the charitable service of the people we will soon become. We treat our future selves as though they were our children, spending most of the hours of most of our days constructing tomorrows that we hope will make them happy. Rather than indulging in whatever strikes our momentary fancy, we take responsibility for the welfare of our future selves, squirreling away portions of our paychecks each month so they can enjoy their retirements on a putting green, jogging and flossing with some regularity so they can avoid coronaries and gum grafts, enduring dirty diapers and mind-numbing repetitions of The Cat in the Hat so that someday they will have fat-cheeked grandchildren to bounce on their laps. Even plunking down a dollar at the convenience store is an act of charity intended to ensure that the person we are about to become will enjoy the Twinkie we are paying for now. In fact, just about any time we want something — a promotion, a marriage, an automobile, a cheeseburger — we are expecting that if we get it, then the person who has our fingerprints a second, minute, day, or decade from now will enjoy the world they inherit from us, honoring our sacrifices as they reap the harvest of our shrewd investment decisions and dietary forbearance. [But] our temporal progeny are often thankless. We toil and sweat to give them just what we think they will like, and they quit their jobs, grow their hair, move to or from San Francisco, and wonder how we could ever have been stupid enough to think they’d like that. We fail to achieve the accolades and rewards that we consider crucial to their well-being, and they end up thanking God that things didn’t work out according to our shortsighted, misguided plan. Even that person who takes a bite of the Twinkie we purchased a few minutes earlier may make a sour face and accuse us of having bought the wrong snack.

This gives another layer of meaning to Albert Camus’s assertion that “those who prefer their principles over their happiness, they refuse to be happy outside the conditions they seem to have attached to their happiness.” Our in-the-moment principles and attachments, after all, may be of no concern to our future selves in their pursuit of happiness.

In the remainder of Stumbling on Happiness, Gilbert, who argues that “the mistakes we make when we try to imagine our personal futures are also lawful, regular, and systematic,” explores the sometimes subtle, sometimes radical changes we can make in our everyday cognitive strategies in order to avoid ending up unhappy and disappointed by unlearning because we set goals for the people we are when we set them rather than the people we become when we reach them.