Rabbi Ari Zivotofsky

Some people go deep into Torah. Others dive into science. Rabbi Dr. Ari Zivotofsky? He does both—without needing to come up for air.

As a professor of neuroscience at Bar-Ilan University, his day job involves studying eye movement and the mysteries of human cognition. It’s serious, complex stuff. But what makes Zivotofsky unique isn’t just his academic sharpness—it’s the way he ties that same intellectual curiosity into Torah, halacha, and Jewish history.

Born and raised in the U.S., Zivotofsky learned at Yeshivat Har Etzion, and earned an alphabet of degrees—from Cooper Union to Hofstra, NJIT, and Yeshiva University’s Revel Graduate School, capping it off with a Ph.D. from Case Western Reserve. Then came aliyah in 2000, and with it, a life of teaching, traveling, and tracing lost Jewish threads—literally.

He’s best known in many circles for one mitzvah: Techeiles, the mysterious blue thread of tzitzis lost for centuries. Through meticulous research and hands-on investigation, Zivotofsky helped bring Techeiles back to life. His work with the Ptil Techelet Foundation has been key in identifying the Chilazon, the elusive sea creature mentioned in Chazal, and helping reestablish the dye’s use based on halachic and scientific criteria.

But Techeiles is just one chapter in a much larger book. Together with his longtime partner-in-exploration, Dr. Ari Greenspan, he’s been on countless “halachic adventures“—literally flying to remote corners of the world to document, preserve, and sometimes even revive ancient Jewish customs on the brink of vanishing. Whether it’s tracking down forgotten kashrut practices, learning about rare shchita techniques, or rediscovering obscure Jewish foods, Zivotofsky isn’t content to read about the past—he wants to taste it, touch it, and pass it on.

His writing appears frequently in Jewish Action, where his articles are part adventure story, part halachic primer, and part invitation to ask: “What else don’t we know?”

What makes his work so compelling is that it never feels like a lecture—it feels like a discovery. Whether he’s in a lab or a Libyan synagogue, he’s showing how Jewish memory and mitzvos are alive, waiting to be noticed, restored, and lived.

For those who wear Techeiles today, or even just know what it is, Rabbi Dr. Ari Zivotofsky is one of the reasons why.