Rebirth or Regeneration?

As a biologist, I often find myself looking to the natural world to better understand the spiritual. Whether it’s learning how to wait patiently on God from quiescent cells or considering what stem cells might have to say on the topic of calling, reflecting on what I do understand helps me make sense of what I don’t (yet) understand.

I’ve recently found myself pondering the symbolism of baptism and the mystery of what it means to be “born again.” Is baptism just a matter of getting dunked in a glorified bathtub minus the bubbles and bath bombs? Does something more happen than just the interaction between the water molecules and my body?

My church background did not provide me with a formal theology on baptism, but rather a working knowledge that baptism by immersion was a reenactment of Christ’s death and resurrection. It also symbolized an internal spiritual transformation—the death of old things and birth of a new, spiritually reborn person.

Of salamanders and planarians

In nature, perhaps the closest thing to spiritual rebirth is regeneration, the ability to regrow lost or damaged parts.

Fire salamander

Some species of lizard can regenerate lost tails, salamanders can regrow amputated limbs, and starfish replace lost arms. Even humans are capable of regeneration, to an extent—maybe not appendages, but in organs like the skin and liver. The skin is constantly replaced throughout our lifetime thanks to our body’s regenerative capacity; old and damaged skin cells are tossed away, and replaced by new ones. And the human liver can repair itself in response to injury by inducing resident stem cells to awaken from their quiescent slumber and proliferate, restoring any lost liver mass precisely to what it was before the injury.

One of the most remarkable examples of regeneration occurs in a type of flatworm called planarians—pictured at the top of this page. These fascinating organisms can not only regrow parts after injury, but can also regenerate an entirely new organism from a single fragment of the original. In 1901, Thomas Hunt Morgan found that a single planarian can be chopped up into as many as 279 tiny pieces, and each will grow into a new individual. Each bit is less than one percent the size of the original flatworm, yet contains all the information or factors necessary to rebuild an entire organism; that’s an impressive feat, unrivaled by any other organism in nature. A special population of stem cells called “neoblasts” are responsible for this regenerative capacity. Scientists are studying these cells to better understand how they work in simple organisms in hope of discovering insights to apply to regenerative medicine in humans.

But why look to regeneration, instead of birth itself, as a model for spiritual rebirth? One could argue birth is de novo, that it starts from scratch. Fertilization happens when a sperm and egg unite to form a single-celled zygote, which continues to divide and develop from an embryo to a fetus. Once we are born, we cannot reenter the womb and literally be “born again”; birth is a one-time event. But regeneration is restorative and redemptive—of parts that are damaged or lost—and is capable in organisms like the planarian of giving rise to an entirely new individual, using starting materials from the original.

I wonder if spiritual rebirth shares this quality with regeneration. Is birth the best metaphor in that it signifies new life and a new beginning? Or is regeneration a better metaphor, in that the old is not disposed of but recycled, reconstructed and somehow transformed into something new?

Nicodemus the naturalist

In a way, I can’t help but feel like Nicodemus, the scholar who talked with Jesus about spiritual rebirth. When Jesus says, “Unless a person is born again, he cannot see and experience the kingdom of God,” Nicodemus didn’t outright dismiss that radical idea, but sought clarity by asking questions inspired by what he did understand:

“How can a man be born when he is old? He cannot enter his mother’s womb a second time and be born, can he?”

I admire the fact that his questions and responses are rooted in the natural world. The scientist within me compels me to inquire about spiritual things, often from a naturalistic vantage point.

Even after the conversation between Nicodemus and Jesus ends, I am not satisfied. A distinction between natural and spiritual birth is made, but no definition is offered. I am left to pick up the conversation where Nicodemus left off, and I’m okay with that.

In the same passage, Jesus asks, “If I have told you earthly things and you do not believe, how can you believe if I tell you heavenly things?”

I wonder if understanding the beautiful mystery of heavenly things lies in listening and uncovering knowledge from earthly things. If so, birth and flatworms are at least beginning to help me make sense of the mystery of being born again.

Ciara Reyes-Ton has a Ph.D. from the University of Michigan in Cellular and Molecular Biology, and teaches at a college in Nashville.