“The fate of the world depends on the Selves of human beings,” pioneering educator Annemarie Roeper wrote in her meditation on how poorly we understand the self. Indeed, while philosophers may argue that the self is a toxic illusion and psychologists may insist that it’s forever changing, we tend to float through life anchored by a firm conviction that the self is our sole constant companion. But when psychologist David DeSteno asks “Can the present you trust the future you?” in his fantastic exploration of the psychology of trust, the question leaves us — at least, leaves me — suddenly paralyzed with the realization that the future self is in many ways fundamentally different from the present self. Our emotions and beliefs and ideals are constantly evolving — Anaïs Nin put it perfectly: “I am a series of moods and sensations. I play a thousand roles… My real self is unknown.” — and even biologically, most cells in the our bodies are completely renewed every seven years. How, then, do we know how “we” are? How do we hold the “self” with any sense of firmness?

Over the past decade, the emerging field of experimental philosophy — a discipline that pursues inquiries about the human condition traditionally from the realm of philosophy with the empirical methods of psychology — has tackled this paradox, along with its many fringe concerns spanning morality, happiness, love, and how to live. In this fascinating video from the 2013 HeadCon seminar shot by TED Talks film director Jason Wishnow, Yale University professor and experimental philosopher Joshua Knobe, editor of the anthology Experimental Philosophy (public library), takes us through some mind-bending, soul-deconstructing thought experiments that push our notions of the self to the limit and past it, into a new understanding of our basic existential anchor.

Although the full talk is remarkable in its entirety and is well worth the watch, here is what I find to be Knobe’s most poignant pause-giver:

One specific thing [has] really been exploding in the past couple of years and this is experimental philosophy work on the notion of the self. This is work on questions about what is the self, how does the self extend over time, is there a kind of essence of the self, how do we know what falls inside or outside the self?…

Philosophers have called [this] the “question of personal identity.” It’s a question in philosophy that goes back, at least, to the time of John Locke. It’s one that philosophers are still talking about up until the present day. You can get a sense for the question pretty easily just by thinking about a certain kind of initial question, and it’s this:

Imagine how the world is going to be a year from now. A year from now there are going to be all these people in this world, and one of those people is going to have a very special property. That person is going to be you. So, with any luck a year from now, there’ll be someone out there who’s you. But what is it about that person that makes that person you?

At this moment you have a certain kind of body, you have a certain kind of goals, and beliefs, and values, you have certain emotions. In the future there are going to be all these other people that are going to have certain bodies, they’re going to have certain goals, certain beliefs, certain emotions. Some of them are going to be, to varying degrees, similar and, to varying degrees, different from yours; and one of those people is going to be you. So, what makes that person you?

[…]

Imagine what things are going to be like in 30 years. In 30 years, there’s going to be a person around who you might normally think of as you — but that person is actually going to be really, really different from you in a lot of ways. Chances are, a lot of the values you have, a lot of the emotions, a lot of the beliefs, a lot of the goals are not going to be shared by that person. So, in some sense you might think that person is you, but is that person really you? That person is like you in certain respects, but … you might think that person is kind of not me anymore.

Once you start to reflect on that, you might start to have a really different feeling about that person — the person you’re going to turn into. You might even start to feel a little bit competitive with that person. Suppose you start saving money right now. You are losing money and he or she is the one gaining the money. The money is being taken away from the person who has the values, the emotions, and the goals that you really care about and going to this other person.

Be sure to watch the full talk — you’ll be glad you did — and dive deeper into this fascinating fledgling field with Knobe’s second volume of Experimental Philosophy, featuring fourteen of the most influential recent essays and articles at this illuminating intersection of philosophy and psychology.