Human change has been a focal point of contemplation—indeed, an intellectual puzzle—for much of Western history. Consider my revision of an ancient riddle known as “The Ship of Theseus.” Imagine a ship. It’s a wooden ship. For fun, we’ll make it a pirate ship—the Black Pearl from the Pirates of the Caribbean franchise. It’s been at sea for ten years. Over that decade, as it enters and exits ports, weathers storms, and suffers violence, the Black Pearl needs repairs. In fact, every single component must be replaced. Piece by piece—the boards, the metal, the canvas of the sails—every part is replaced with new parts. Yet everyone who encounters this ship continues to call it the Black Pearl. If every single part has been replaced, is this the same ship that it was a decade ago? On what basis do we decide? Put differently, what makes the Black Pearl, the Black Pearl?

Regarding people, things get more complicated. Ships, at least as far as I’m aware, don’t have consciousness or memories. But, in various ways, people typically do. I’ve heard that over the span of ten-to-fifteen years, every cell in the human body dies and is replaced by new ones. After poking around online, I’m not sure if that’s true. But let’s suppose that it is. If no part of your body were exactly the same as it was, say, ten years ago, could we accurately claim that you are the same person you were last decade? If your answer is yes, then why? What, that is, would you say makes you, you?

Such questions may seem like silly academic games, but the mysteries of human change often reveal themselves in our lived experiences. For example, when a beloved family member lives with dementia, and they no longer remember their own history or intimate relationships, what sustains them as a self, as a person who still relates meaningfully with others (see John Swinton, Dementia [Eerdmans, 2012])? Similar questions arose for my wife, a social worker who spent over a decade working with folks who were homeless. In many cases, especially for those who’d suffered traumatic brain injuries, those living on the streets were barely recognizable as the same people whom friends and family had known prior. To what extent were they the same people as before, and how does our answer shape how we relate to them?

The mystery of human change is central to a number of moral discussions. Our era of rapid scientific progress has led to surprising developments in ways that we can alter or enhance our bodies, whether through systematic dieting, cosmetic surgeries, or other tech-driven metamorphoses. Some have even poured large sums of money into searching for ways to transfer human minds to a non-biological platform. What is a responsible moral stance toward such things? How should the church respond?

I wish I had the answers to those questions! As a starting point, though, I’ve found it useful to examine what our Scriptures suggest about the nature of human change. In particular, I’ve had opportunities to study human transformation in Paul’s letters.

Paul doesn’t view change merely as something that happens to people. For him, change is part of what makes us who we are. Christ-believers have become a “new creation” (Gal 6:15; 2 Cor 5:17) through a radical experience of change: an “old self” was crucified, producing a new self that lives in and with Christ (Gal 2:19–20; Rom 6:1–11; Col 2:11–15; 3:9). In the present, they are being transformed “from one degree of glory to another” (2 Cor 3:18 NRSV) and should be “transformed by the renewing of [their] minds” (Rom 12:2 NRSV). Such change, all of which occurs in the community of Christ’s body, could take unpredictable directions, based on decisions about things like marriage, diet, and relationships (1 Cor 7–10; Rom 12–14). At Christ’s return, believers’ bodies will be transformed to dwell in God’s presence (1 Cor 15:35–57; Phil 3:21; cf. 2 Cor 5:1–10). Transformation thus characterizes the experience of being in Christ from beginning to end—an idea that Wesleyan readers surely can embrace!

If we take this seriously, then we can begin to build a theological framework in which to consider contemporary experiences of change. Especially important is that believers undergo transformation within the body of Christ, the sphere that, as I’ve written before, determines who we are. Furthermore, we are called to participate with God’s Spirit in processes of moral transformation, what Wesleyans call sanctification. For Christians, that is, a substantial part of what makes you, you, is that you have been and are being transformed as a part of Christ’s body. That doesn’t tame the mysteries of human change. But it’s foundational to understanding who we are, and who we are becoming.