Abraham was a zealot. He was so intolerant of false notions that he smashed his father’s idols. That nearly cost him his life, but in the end, his new concept of one invisible, omniscient and omnipotent Creator caught on so well that today followers of Abrahamic religions comprise more than half of the world’s 8 billion people.

We all have a little Abraham inside us. I had an Abrahamic moment back in the early 2000s, and in a small way, I got some serious unexpected flak for it.

The idol I had set out to eradicate was more subtle than a pagan statue—it was a false idea. And of course, you can’t demolish ideas with a hammer. You need persuasion. And if you are standing at the front of a lecture hall in the role of professor at a secular university, and you want to take down an idea, you had better do it with facts and arguments, not polemic and rhetoric.

And yes, I was prepared. Having earned a doctoral degree in the University of Toronto’s Department of Zoology, I was exceptionally familiar with the ins and outs of the idea I was about to challenge—the most cherished dogma among biologists for a century and a half: Darwin’s Theory of Evolution, the idea that the diversity of life on earth is the result of random mutation and natural selection.

The classic image is the “Tree of Life” in which humans are a recent branch tracing back to apes, then to earlier mammals, and back to reptiles, fish, and ultimately to the one-celled organisms from which all life is supposed to have evolved over many hundreds of millions of years.

The truth is I believed it too. Unquestionably. Until Chabad found me, at a weekend getaway for Jewish college students. Some rabbi was giving a talk on Love, Dating and Relationships (Yes, it was Manis Friedman), and although my curiosity was piqued, my secular background screamed in the back of my mind: “Don’t fall for it! It’s religious dogma from the dark ages. Religion is just a crutch for people who can’t take the truth.”

We got into a six-hour argument, during which he had answers for all my questions and questions for all my answers. I was left in a state of suspended disbelief, not quite the atheist I thought I was, yet not ready to take Torah at face value.

Over the following decades, I became an avid reader and public speaker on the subject of the interplay of authentic science and traditional faith, including, of course, Darwinian evolution and all the related questions of cosmology and the age of the universe.

My talk that day was to the hundred undergraduates who had registered for my accredited Faith and Science course, and that day’s lecture was Evolution Myths and Facts. (You can find the gist of my talk here.)

But as prepared as I was to give the talk, I was certainly not prepared for what happened immediately afterward. “Are there any questions?” I had barely gotten the words out when one very vocal young man let loose with a barrage of challenges of his own.

“I can’t believe what this guy is getting away with! Look at him! With that beard and the skullcap? He’s trying to indoctrinate you. Are you going to let him get away with this? If what he is saying is true, why doesn’t any other professor talk like this? We can’t take this lying down.”

Several students reacted immediately, but not quite as he had hoped. The blue-eyed blonde said, “Why are you so nervous? He told us on day one, you don’t have to believe like him. You just have to understand the information.”

Then an Asian student chimed in, “What’s the matter, the scientific citations don’t exist? The math doesn’t add up?”

Then a fellow with a turban joined the fray, “Who is making polemic arguments here? It’s your claims that are spurious.”

Our rebel glanced from one student to the next in shock, like a deer in the headlights. He sank back into his chair. This gave me a chance to play ‘good cop.’ “I’m very interested in what you have to say. I have an office hour before class next week. Why don’t you come see me and we can explore your perspective at greater length then.”

I took his name (it sounded very Jewish), and we confirmed for the next week. Of course, I had my tefillin ready for his visit. “Hmm. Your name sounds Jewish,” I said with a smile as I started to take my tefillin out of their bag. He pulled up his sleeve, “I knew I wasn't going to get out of this without putting on tefillin.”

I approached to help him wrap the tefillin and he took them before I had a chance. “I’ve got this,” and he made the blessing and started wrapping the straps himself. I opened the siddur to the Shema prayer, but before I could hand it to him he was already reciting it by heart … all three paragraphs. I asked him if he’d like to say more, and he grinned as he commented, “I’m not going to daven the whole Shacharit!”

This was definitely not the meeting I was expecting. As I put away the tefillin, we started to chat.

“Where are you from?”
“Here in town.”
“Where did you go to school?”
“Hebrew Academy.”
“So you are living at home?”
“No. Downtown.”
“In residence?”
“No, off campus.”
“Sharing a place with a few people?”
“Just one.”
“A guy or a girl?”
“A girl.”
“Is she Jewish?”
“No.”

I looked at him. He looked at me. We just sat there quietly for what seemed like a really long time. We both knew that this wasn’t about Darwin. This was about the girl.

Because if Darwin is right, then the Torah may be wrong. And if the Torah is wrong, then Judaism is wrong, and living with a non-Jewish girlfriend is fine.

But what if Darwin is wrong? Well, then maybe Torah is right. And if Torah is right, then maybe living with a non-Jewish girl is wrong.

That’s what he was fighting for. Not the origin of species. It was about the girl.

As Aldous Huxley, whose family was among the leading evolutionists of yesteryear, famously said, “We objected to the morality because it interfered with our sexual freedom.”

For him, and for me, letting go of Darwin’s Tree of Life was a necessary prelude to embracing the true Tree of Life, the Torah. And once you hold on to that, you never want to let go.

As we say after the Torah reading, “It is a tree of life to those who hold fast to it.” And that’s a kind of zeal that’s really not so scary. As the verse continues, “Its ways are pleasant and all its paths are peaceful.”