I had ambitious plans for my summer research. My list was long, and I intended to conquer it.

Instead, I spent the first weeks chasing something I couldn’t even see.

Near the end of last summer, I stumbled onto some baffling results. Before I could investigate, students returned to campus, classes resumed, and the results were pushed to the back burner.

That semester, like every fall semester, I taught a course called SEA-GENES, where students conduct a semester-long genetic screen of a bacteriophage—a virus that infects bacteria. Throughout each semester, we clone each gene in a phage genome and ask what role its protein product plays in the life of the virus and how it affects the host bacteria.

Our hope is to illuminate the function of genes no one yet understands. Along the way, students discover that science is less about memorizing answers and more about learning how to ask better questions, to perform experiments to answer those questions, and to interpret the experimental results well.

For five years, our work had steadily progressed. We were preparing to publish the first genetic screen from the bacteriophage Isand3, identifying the viral genes that interrupt the growth of the host bacteria, Mycobacterium smegmatis.

Then, last fall, everything stopped working in our GENES course.

None of our bacteriophages would infect our bacteria.

We repeated experiments. We checked protocols. We remade solutions. The students patiently worked through all the explanations we could think of with me. In troubleshooting, they learned a great deal about how science actually works, even as my frustration mounted.

One night around three in the morning, I woke with an unsettling thought. What if the bacteria I thought were Mycobacterium smegmatis weren’t Mycobacterium smegmatis at all? Perhaps a contaminant was the reason our experiments stopped working!

The next morning I discarded my cultures, prepared fresh media, and thawed new bacterial stocks from the freezer. The results confirmed my suspicion.

I had a purity problem.

The end of the fall semester pushed the purity problem to the back burner again but after contamination ruined several experiments this summer I knew we had to address the problem head on. With the help of a colleague and a student, we tore into the lab. We scrubbed every surface, every pipette, every water bath, and every piece of equipment with three different disinfectants. We discarded stock solutions, re-sterilized glassware, and remade media from scratch. Only after nearly a week of work did we dare begin again.

Success!

No more contamination. Control experiments behaved as we expected and we got results that we could easily interpret! 

During that week of cleaning, I happened to read Philip Vinod Peacock’s letter, Communion Is Not the Same as Agreement, alongside Kristin Du Mez’s essay, The Problem with Purity. It struck me that I was spending my days trying to achieve purity in one setting while reading critiques of purity in another. Of course, “purity” means something very different in a laboratory than it does in churches and denominations.

Every experiment depends on defined conditions. The question is never whether we set up those conditions, but what the conditions are for. In my laboratory, purity serves understanding. It removes the static so I can better see the astonishing complexity of God’s creation. Sterility is a condition. Purity is not the goal; discovery is. 

When purity becomes the goal, however, it no longer serves discovery—or even truth. It begins serving fear. Instead of helping us see the world more clearly, it teaches us to shrink the world until only the familiar remains.

I still don’t know what contaminated my cultures. I doubt I ever will. But I know why I wanted the contaminant gone. I wasn’t trying to create a simpler world. I was trying to better understand the real one.

That, I think, is the difference.

Purity can serve wonder, or it can serve fear.

In the laboratory, purity allows me to study the extravagant diversity of creation. If purity itself became the goal, my laboratory would be empty.

Perhaps the church faces a similar temptation. There are conditions worth keeping, but they exist to bear faithful witness to the God who delights in abundance, not to shrink creation until it feels manageable. Abundance and diversity are everywhere in the natural world. The earth teems with life; Paul imagines the body of Christ as many different members rather than identical parts (I Corinthians 12).

Perhaps Creation teaches the same lesson Philip Vinod Peacock articulated so beautifully: communion is not the absence of difference but the patient work of discovering how very different creatures belong to one Creator.