Isaac Chenchiah (PhD '04), Solid Mechanician and Biomimicry Engineer

One would be hard pressed to find a single home discipline for Isaac Chenchiah. From mathematics to solid mechanics, and from aerospace engineering to plant mechanics, Chenchiah follows his interests regardless of academic boundaries. As a theoretician, his forte is in finding the truth of numbers as they are expressed in physical reality, and as a deeply spiritual person, he is unafraid to consider the boundaries separating the knowable from the intrinsically mysterious.

Born and raised in Chennai, Chenchiah's education at IIT Madras prepared him well for his graduate work at Caltech, where he studied under the direction of fellow IIT Madras alumnus Kaushik Bhattacharya. In the discussion below, Chenchiah conveys his gratitude for Bhattacharya's mentorship and his sensitivity toward treating each student according to his or her strengths. For Chenchiah, the goal was to pursue his studies without the distractions of computation, something for which he felt he was not yet ready. Following his thesis research on multiphase elastic solids, Chenchiah desired for a postdoctoral opportunity in Europe, as much for the cultural as well as scientific experience. It was also during this time that Chenchiah embraced the vast possibilities in biology, both as a matter of pursuing research inspiration and in applying his multitude of expertise to solving real-world biological challenges.

Now at the University of Bristol, Chenchiah is deeply appreciative that he is able to work in an environment that reflects bedrock Caltech sensibilities: low administrative barriers for collaboration across departments, and a research culture that unites theorists and experimentalists. And finally, he now feels ready to wade into the depths of computation and simulation, which will help him to answer some of the most challenging and fascinating questions. If, for example, we are ever to know what it is like to be a bee, Chenchiah's models, combined with the depth of his imagination, will help us get there.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It's Wednesday, December 13, 2023. It is my great pleasure to be here with Professor Isaac Chenchiah. Isaac, it's wonderful to be with you.

ISAAC CHENCHIAH: Thank you, David. A pleasure for me, too.

ZIERLER: Isaac, to start, would you please tell me your current title and institutional affiliation?

CHENCHIAH: Associate Professor at the School of Mathematics, University of Bristol.

ZIERLER: The School of Mathematics, is that to say that your primary appointment is in Mathematics, and does that make you, at least as a professor, a mathematician?

CHENCHIAH: Yes, of applied mathematics. In the U.K., mathematics is understood more broadly than in the U.S. It very much includes applications of mathematics. I'm on the applied end of mathematics, and that kind of work is typically done in schools of mathematics in the U.K.

ZIERLER: Beyond the cultural particularities that define this as applied mathematics, do you also consider yourself a scientist?

CHENCHIAH: Yes, I do, and also an engineer.

ZIERLER: Everything. You've got it all covered.

CHENCHIAH: Only these three! There are many other fields!

ZIERLER: What are the research questions that blend mathematics, engineering, and science for you? What are the big questions that you've looked at in your career?

CHENCHIAH: One big question—I think it will be too much to say that I've looked at it; "looking at it" would be better—would be trying to understand large engineering structures—imagine something you might want to put into space—that you would like to have, let's say, in a very compact form here on the ground, and unfurled once it is deployed into space. What I would call this is a morphing structure, or more generally, a structure that has multiple stable states and you would like to change it from one state to the other, maybe a compact state and an elongated state. I'm going to just call them morphing structures. One large strand of my research is observing two things. One is that a lot of these mimic things that happen on a much smaller length scale, for example you could have a metallic alloy that has multiple stable states. In fact, I worked on while at Caltech. The idea is that we could maybe use techniques or principles from nature and transfer them over to engineering and design our structures inspired by what nature does. That's one part of it. The other part of it is that a lot of this work on morphing structures is done by engineers, and it's very good work, but I would like to take one step back, look at it from a more systematician's viewpoint, or maybe a more mathematical viewpoint, and ask, do I see common themes, principles, paradigms that we can then identify and exploit to do it even better?

Engineering Inspiration From Nature

ZIERLER: Because you take cues from nature, do you have a preference over the terms bioinspired research versus biomimicry? Do those essentially mean the same things to you?

CHENCHIAH: Not necessarily. Here is one analogy I can give you. Imagine, let's say 150 years ago, you are trying to build a flying machine. Biomimicry for me would be trying to understand how to build a structure with flapping wings. I am really trying to mimic a bird. Bioinspired would be looking at a bird and saying, "Aha! Wouldn't it be great if I, too, could fly?" But how I achieve that would have nothing to do with a flapping wind. I'm inspired to do something that nature does but I'm going to do it in a very different way. For me, that's bioinspired. More specifically, I could say, "Let me do something that achieves what nature does using the same methods," and that would be biomimicry. For me, biomimicry is a subset of the bioinspired.

ZIERLER: Of course nature has the obvious advantage of evolution, which we do not, in the here and now. How do you overcome that limitation? How can you be inspired or mimic what happens in nature without having the benefit of evolving your projects over millions of years?

CHENCHIAH: Well, we could do millions of computer simulations, so it's not entirely true that we don't have the advantage of evolution. We can speed up evolution on a computer. Also, you could say, actually, nature has done the work for me. Why do I need to repeat it again? I could say, whatever forms nature evolved clearly are, if not optimal, at least good enough for a large class of environments, so let me just go with that.

ZIERLER: What aspects of your research are really fundamental, curiosity-driven, and where are you motivated by specific applications, albeit for human health, for industry? How does that research break down for you?

CHENCHIAH: I would say in my heart I am motivated purely by curiosity almost entirely. I'm going to do something maybe unusual; I'm going to quote a rabbi. This famous rabbi, Hillel—"If I am not for myself, who is for me? If I am only for myself, what am I?" The first part is curiosity, right? I am for myself. I want to do things that inspire me, that attract my attention, that I am passionate about. That's how it starts. But if I just stop with that, I am isolated. I don't connect with the rest of the world, and others may never come to see what work I have done or what inspires me. They can't contribute to me, and I can't contribute to them. Applications are a way of moving from individual to community. I say, here are my insights, my passions. How does it fit with other people's interests and passions, with needs out there? Two different curiosity-driven people can come together and do more than the sum of their parts, but for each of them the other might look like an application.

ZIERLER: Another binary for you to consider—theory and experimentation. Where is your research mostly sitting?

CHENCHIAH: Almost entirely on the theory side, but I do work with experimentalists. That's where collaboration comes in as well.

ZIERLER: Do you maintain a lab, or it's all calculations for you?

CHENCHIAH: It's all calculations for me, but I have colleagues who maintain labs.

ZIERLER: What would it look like for you to have an idea and to work it out, simulate it, theorize it, work out the equations, and then bring that to a colleague? What does that workflow look like?

CHENCHIAH: It typically starts actually much before I fully formulate the idea myself. Typically, I have an idea which maybe I flesh out partially in my mind and then I talk to people about it and say, "Look, here's what I'm thinking." It often falls on deaf ears, because people's interests are different, but occasionally I see a colleague who says, "That looks interesting, and here's what we're doing in my lab." Then we can sit together, and the idea probably gets morphed into something different from what I initially thought, because I spoke with someone.

ZIERLER: Tell me more broadly where you fit in at the University of Bristol. Is this the kind of research that Bristol is known for? Is there a critical mass of researchers who are doing the same kind of approach to research as you are?

CHENCHIAH: Yes and no. Broadly in Bristol I have found barriers to collaboration between different faculties and schools are very low, so I can easily talk to someone in, say, biology, and supervise students in, let's say, in common with engineering, so I've had many students who have been supervised by myself in the faculty of science and somebody in the faculty of engineering. That's extremely easy to do administratively. In terms of the specific questions that I'm asking, there are many others who ask the same genre of questions, but I think if you look at mathematics and morphing structures, I think I'm the only one asking that at Bristol. But interdisciplinary work is very common. There is a culture of people talking across faculties.

ZIERLER: We're all thinking about machine learning and AI these days. Is that relevant for your research? Are you leaning on these new technologies?

CHENCHIAH: I am beginning to. A student who graduated some months ago, jointly supervised by two of us in mathematics, myself included, and two in biochemistry, was trying to understand wound healing. We wounded drosophila (fruit fly) wings, imaged the healing process, and we looked at the images and used machine learning to understand which healing processes—for example, cell divisioncell growth, cell movement—contributed to the healing. This was a machine learning algorithm that the student designed to look at lots of video images and pick out what's going on. Is a cell dividing? Is it moving? Is it dying, perhaps? I wouldn't say I'm an expert on this. It's something I'm getting into now.

ZIERLER: What would you say is your home discipline where you feel most comfortable as a leading scholar, and where do you really have to read up on the literature in order to understand what is happening and how you might utilize it?

CHENCHIAH: I would say definitely I am a newcomer to biology, so anything that involves biology, I would definitely have to read up and very likely also have to talk to people about it. Home disciplines would be, I would say, something at the interface of solid mechanics, structural mechanics, and the branches of mathematics that traditionally fit into those.

ZIERLER: Is fracture mechanics part of your work as well, how things break down?

CHENCHIAH: Not at the moment. I did take a course on Fracture Mechanics from Ares Rosakis at Caltech, but I did not pursue that aspect of mechanics. It may come in the future.

Gateway to Biology

ZIERLER: How and at what point in your career did you get more interested in biology?

CHENCHIAH: About a decade ago, I would think. It came because I noticed some work on a certain virus, bacteriophage T4, which actually is a very well-studied virus. It has a very interesting mechanism for infecting bacteria. Some of my colleagues, in fact, my doctor grandfather, so to speak, Richard James, worked on it, which attracted my attention. That turned out to be a gateway drug to get into biology.

ZIERLER: The scales that you're operating at are remarkably diverse. A virus, it doesn't get much smaller than that. Then you're studying things like bees flying and locomotion. Is it all the same, regardless of the scale, or is it very different science depending on the size of the biological system that you're working on?

CHENCHIAH: I would say both, actually. There are aspects that are very different, and I tend to abstract out what I think is common. Bacteriophage T4, for example, has a tail-sheath that can take two stable states, and we have tried to mimic that in an engineered structure. That would be a case of saying, look, I'm trying to see something common between something I can hold in my hand, a metallic tube, and something that's on the scale of a virus. On the other hand, there are many other things going on the bacteriophage T4 virus that I have completely not seen and am not trying to mimic. My own research is focused on seeing commonalities, but there's much more to science than that.

ZIERLER: What does the bioinspired or biomimicry academic community look like? What are the conferences to go to? What are the journals to write in? What are the societies to belong to?

CHENCHIAH: There are specialized journals for biomimicry, although I think a lot of good work is done in journals that have a broader audience, so let's say journals at the interface of mathematics and biology. More fundamental work is often published there. So it may not be biomimicry at the engineering end, but it's biomimicry one or two steps removed from engineering but laying the foundation for it. There are many, many journals these days that look at theoretical biology or biomathematics and so on. Similarly the community is also quite diverse. There are the people who are really trying to do nuts-and-bolts engineering—that's metaphor, not literally—and there are people who are trying to understand commonalities more conceptually. Now I would like these communities to talk to each other a bit more, which is why I try to work a lot with engineers, to bring the biomimicry people along with the mathematical biology people.

The Spiritual Dimension

ZIERLER: A topic that we touched on before we hit record is your interest in religion and spirituality. Do you keep those worlds separate? Is there any interface between your personal interests and belief and what you do as a mathematician, a scientist, and an engineer?

CHENCHIAH: They are almost entirely separate with one significant exception. It's going to be easier to communicate if I give you a concrete example. Let's take a religious hot-button issue, not hot in a political sense but hot in a conceptual sense. Let's compare Judaism and Christianity. These two religions famously disagree on whether a certain person is the messiah or not. Now, here is something I would like to propose. What if we stepped back from the debate and asked ourselves, let's look at Judaism not as having some set of ideas about the messiah but as a conceptual system, as a coherent whole. Of course there's nothing new there. Lots of people have done this. It's an entire tradition. Let's look at Christianity as well, and since there are many Christianities, let's say Catholicism to be particular. Now if you look at the Christian, specifically Catholic, understandings of the messiah, and Jewish understandings—but maybe let's pick one of them, let's say Modern Orthodox Judaism—of the messiah—if you put these side by side, it's not at all clear that they are talking about the same thing. Now, someone with a systematician's mind or eye, who is sufficiently knowledgeable about both traditions, could ask, to what extent are these two people disagreeing with each other, to what extent are they just talking past each other, and to what extent could you say actually these two might be true simultaneously, or maybe there's some way we could tell they are both wrong, to some extent.

That is the kind of question in fact that I have been working on in my private time. I would say that again the inspiration is not very different from asking, how can a virus look similar to a space telescope? You're trying to look for something in common, but the details of how the systems work may be very different. I would say, in this sense, I have a certain vision that scientists can contribute more to theology, maybe theology specifically rather than just religion, not in the sense of saying this is right and this is wrong, or I believe it or I don't believe it, or it influences my life, but in the sense of trying to bring together our expertise in understanding large systems and seeing analogies between systems.

ZIERLER: I wonder if you see these dual interests as somewhat anachronistic here in 2023 where—I don't have the numbers behind me, but most scientists are not terribly interested in religion. Most scientists would be eager to tell you that they are atheists. I wonder if you are drawing on a deeper tradition from centuries ago where we didn't have terms like "scientist" but we had natural philosophers, and great people that we would now called scientists were quite comfortable thinking in theological terms. I wonder if you're drawing on a deeper tradition.

CHENCHIAH: Partly that, yes. That's certainly an inspiration. But also, I think part of the disinterest—I mean non-interest—in religion comes because people don't step back and say, "Actually, this is a really interesting phenomenon. Let me not take a personal stake in whether it is true or false. Let me just study it as a phenomenon." One could study, for example, a certain religious phenomenon without having a personal stake in whether you think it's right or wrong or whether it affects you or not. Actually, I think scientists ought to be able to do this. Now, if I am really passionate about ants, I might not want to injure them by doing some experiments on them, so I may stay away from ant biology. If I particularly detest spiders, I may stay away from the biology of spiders as well. So, I think people's intense feelings about religion are part of a barrier to a more clear-minded understanding of what religion could be or just how it is.

Something of a sociologist mindset of detachment combined with a scientist's curiosity I think is what I am advocating here. I would tell someone, let's look at this common claim that religion contributes to violence in the world. I would say, hey, look, there's this French anthropologist, René Girard, who made the exact opposite claim, that the world would be even more violent without religion, and religion reduces violence in the world. There's a considerable body of work, very influential by now, arguing for this fairly persuasively, I think. Have you looked at that? Then the only scientific thing to do would be to actually engage with Girard's work or similar work, and ask, look, maybe religion contributes to violence in the world, but maybe it would be even worse without religion. I think these are the kinds of questions that scientists are actually well trained to ask in principle but don't apply it to religion because they think immediately of what do I believe or what do I not believe. I would encourage them to step back a bit from personal beliefs or disbeliefs and look at the world around you, which includes religion as a major component.

ZIERLER: Have you been able to do this in your own work? Do you try to point to your own experiences as an exemplar of what scientists can contribute?

CHENCHIAH: [laughs] Yes, I have tried. I think when I talk to theologians, let's say those working on Christian-Jewish relations, I think this kind of an approach is quite new to them. For people trained in humanities, I think a more science or engineering way of looking at the world is also new. So I think there are some barriers to overcome. It might be like the early days of physicists trying to talk to biologists. It took a long time, I hear from my colleagues, for biophysics to really become a thing. So, I think it will take a while. One needs patience for communities to open up to each other, but I think it's an effort worth making.

ZIERLER: I wonder if you've reflected on your own life experiences and background as a reason for these interests. Being from Southern India, having a Christian background, being educated in the United States, in Germany, working in the U.K. right now, you have a very wide purview. I wonder if that's an inspiration to wanting to look at things in a deeper and broader way.

CHENCHIAH: I think so. I think the experience of moving from India to southern California when I was 21 certainly made me aware of how different the world could be from my own experiences, and how much I could learn if I opened myself up to new things. I think it was replicated again when I began to study Judaism. This happened maybe seriously in my late thirties. It was just an overwhelming sense of an immensely rich world that I had been completely unaware of, with so much wisdom and insight to offer, but even if you didn't care about wisdom and insight, just interesting modes of reasoning. I think one could easily look at let's say the Talmud and simply ask yourself, what are the tools of reasoning the rabbis bring to various issues they are working on? It just opens an entirely new intellectual world, even for someone who had no interest in Judaism per se. That's the kind of experience I've had, the entire hidden world. Hidden from me, that is. I think this is the excitement of a new discovery. I think the experience of moving from India to the U.S. at 21 somehow has made me a firm believer in the value of this. Expose yourself to a new world. Let another religion, another science, another intellectual discipline encounter you, and maybe even overwhelm you at the beginning, so that you can really taste it and touch it and see it.

From Chennai to Pasadena

ZIERLER: Let's go back and trace that trajectory. Tell me about your childhood. Where did you grow up? What kind of family did you come from?

CHENCHIAH: The city in southern India, on the sea coast, then called Madras, now called Chennai. I grew up in I would say a very normal, middle-class family. My parents were——in a positive sense—proud of their lineage. I had a paternal great-grandfather who was a well-known theologian in India, specifically in Indian Christianity. We had some distinguished lawyers and judges in the family from my father's side. My maternal grandfather was a professor of English literature, and he was one of the few people in India of those days who had been educated in the U.K. He had a degree from King's College London. I was introduced to a lot of English literature as a child through him.

ZIERLER: How many generations back does Christianity go in your family? Do you know?

CHENCHIAH: Yes, roughly a hundred years, so I think that would be three, four generations. I mentioned my great-grandfather. I think he was either raised Christian or his family converted when he was a teenager. Wikipedia actually has an article about this: https://en.wikipedia.org/wiki/P._Chenchiah.

ZIERLER: Is there a British colonial connection to the Christian origin story in your family?

CHENCHIAH: Yes and no. Yes, they embraced Christianity as a result of British missionaries—if I remember right, English on my father's side and Scottish on my mother's side. On the other hand, my great-grandfather worked very hard to come up with an Indianized Christianity—that's not the right way to say this—let's say an indigenous Christianity. In fact, that was the main thrust of his life's work. I don't think that really influenced my upbringing. My family was actually fairly Westernized, looking back. But his own life's work was very—Indianization.

ZIERLER: Were you aware of any Jewish communities in India? There are Jews in India that go back a long, long time. Did you know of any?

CHENCHIAH: Not at that time. Much later in life I did, but not when living in India. If I understand right, India, in fact—the neighboring state of Kerala, has the oldest synagogue in the world outside of the Middle East. You need to fact-check that, but I think I got that right. But I didn't know this until much later, when I was living in the West.

ZIERLER: In Jerusalem there are Indian synagogues.

CHENCHIAH: Oh, I didn't know that!

ZIERLER: Oh, yes.

CHENCHIAH: Okay!

ZIERLER: It's amazing. It's a complete merging of—it's a synagogue like any other, but it's people from India who are members there. It's a remarkable thing.

ZIERLER: Tell me about the IIT system and where IIT Madras fits in.

CHENCHIAH: IITs were set up as elite engineering schools. The initial purpose was to train Indians when the nation was young. I think they were set up in the 1950s. Typically an IIT was set up with help from a Western government, and one from the Soviet Union. IIT Madras was set up with help from then-West Germany. If I remember right, it was the largest educational project funded by the West German government outside of West Germany itself. These were intended to be elite undergraduate engineering institutions but then they also have sciences at the postgraduate level and later on the undergraduate level as well. I experienced them as actually having given me an excellent education as far as engineering goes. Comping the education that I received with let's say an undergraduate at Caltech, I think it compares very well actually. Now, where I think I didn't get what perhaps an undergraduate at Caltech gets, hopefully, is exposure to the larger intellectual world. I didn't have much of an education in humanities. I learned some German. We had to take a compulsory course in economics. Other than that, my education was entirely technical at the undergraduate level, which I now feel was a truncated education, which I'm trying to set right in my own private studies.

ZIERLER: What was your focus as an undergraduate? Was it really applied mathematics and engineering?

CHENCHIAH: It was civil engineering, and I particularly was attracted to solid mechanics and structural engineering. That was what I was particularly focused on. The degree itself was in civil engineering.

ZIERLER: Did you ever consider going into industry, or did you always feel like you were on the academic path and you wanted to look at graduate schools?

CHENCHIAH: I wanted to look at graduate schools. I felt very early on I was on an academic path.

ZIERLER: Here's the question I love asking of international students. How did you hear of Caltech? How did you know about this small school in Southern California?

CHENCHIAH: [laughs] Actually I heard it from colleagues at other U.S. universities. For my undergraduate project, I worked on these so-called shape memory alloys. I was so fascinated I decided I would only apply to grad schools to continue working on that. So I wrote to someone quite well known—Richard James at Minneapolis, whom I have already mentioned—and asked if I could work with him. He said, "Yes, you could apply," but he also mentioned other names, and one of the names he mentioned was his former student at Caltech, Kaushik Bhattacharya, who eventually became my PhD supervisor. I think a few other people mentioned Caltech as well. So, I found out about Caltech from other academic staff in other U.S. universities.

ZIERLER: What year did you arrive at Caltech?

CHENCHIAH: 1998, September.

ZIERLER: Had you been to the United States before? Do you have any family here?

CHENCHIAH: No, it was an entirely new, new, new country.

ZIERLER: What sticks out in your memory? What do you remember from your early arrival?

CHENCHIAH: The car journey back from LAX to Pasadena. I had known knew the U.S. was a rich country, but what I saw from the highway and the buildings around me was beyond what I had imagined. What then seemed to me—and it is true—the wealth of the United States compared to what I had seen in India was unimaginable. I also remember thinking, on that same car journey back, how much hard work and intellectual energy would have gone into building a society like this. For me, the wealth was not just wealth itself. Behind it, I could sense—I think now I would call it a civilizational ethic—behind it. Though I wouldn't have been able to say it in those words, I could sense that this didn't just come out of nowhere.

ZIERLER: Coming from an IIT, how well prepared did you feel when you started graduate school at Caltech?

CHENCHIAH: I would say very well prepared academically. It was a challenging year. I don't think any first-year graduate student at Caltech says it was a walk in the park. It was a challenging year, but in a good way. I didn't think I was thrown into the deep end and allowed to sink.

ZIERLER: What about socially, the culture of Caltech? Was that an easy transition for you?

CHENCHIAH: Surprisingly, yes. It should not have been, and I was and am still quite introverted. In fact, I was very introverted, looking back, and had very few social skills. But somehow [laughs] I managed to get on. I think the international students office had a one-week orientation for international students, and there was a subsequent one-week orientation for all students, so we had two weeks of orientation which helped a lot. There were quite a few—how should I say this—culturally sensitive but also honest conversations about how to interact with people in the U.S., which was very helpful. Also, I think the community was very welcoming. The fellow grad students I met were all relaxed, welcoming, and very accepting of someone from a very different background.

ZIERLER: Did you have contact with Kaushik before you got to Caltech? Was it set that you would be his student?

CHENCHIAH: More or less, yes. It wasn't set in stone, and I think I could have picked a different advisor had I wanted to, but I had email contact with him, he was assigned as my initial advisor, and that didn't change.

ZIERLER: What did it mean to have your advisor as a fellow IIT Madras alumnus? Was that a fun coincidence?

CHENCHIAH: I don't know if that was very important to me, to be honest with you. Now that I've lived in the West for 20 years or more, I am more conscious of my Indianness--not in a bad way; in a good way—and more aware of people's ethnic heritages and backgrounds. Back then, I think it didn't mean anything to me that he was Indian, let alone from IIT.

ZIERLER: What was Kaushik's research then? What was he focused on?

CHENCHIAH: [laughs] Maybe best to ask him, but as far as I could see he was focused on multiphase materials, so multiphase solids, understanding the continuum behavior, the microstructures. And not just multiphase solids; he worked on other things as well when I was there. But probably I would say complex solids where microstructure influences behavior in interesting ways.

Molecular Calculations Absent Computation

ZIERLER: How did you go about developing your thesis topic? What was interesting to you?

CHENCHIAH: I was pretty clear that I didn't want to do any computational work at all. I wanted a thesis that was entirely theoretical. Kaushik was very respectful of that. He was okay with that. He did—and I'm very grateful to him for this—insist that I should take at least one computational mechanics class. If I could go back, I would actually invest more time in that. Nevertheless, he was very respectful of what style of work I wanted to do, and he proposed a problem that very much fit into that, and I said yes to that. He said, look, we have this understanding of how a two-phase solid material would behave.

ZIERLER: What does that mean, two-phase solid material?

CHENCHIAH: Here's an easy analogy. Think of chocolate. Now, if it's really good quality chocolate, if you keep it in the fridge, let's say for a few days, and eat it afterwards, you can sense a difference in taste. This works for ice cream as well. Good quality ice cream, the expensive kind that you buy from an ice cream parlor, if you bring it home and put it in the freezer and eat it, let's say, a day later, you can actually taste the difference. The reason is what has happened is that the phase has changed. The molecules that make up your solid—so ice cream, chocolate, or alloy—used to have a certain pattern of arrangement in the ice cream store, but in your home freezer, where you couldn't reach such low temperatures, they took on a different arrangement. These are what we call two phases. These phases typically have different properties. In this case, they taste different. But coming back to alloys, they could have different strengths, different, say, responses to stress. They are chemically the same substance, but the way the atoms are arranged gives them different physical properties. These are what we call by phases.

ZIERLER: Was this topic particularly well suited to your desire to be really purely theoretical, to not get involved in computation for your thesis?

CHENCHIAH: I think it was. It was not immediately obvious that it would succeed. That's true for any good research. It took quite a while to make progress on it, but yes, I think, looking back, it was well-suited.

ZIERLER: For yourself, why that insistence? Why did you want to keep a certain distance from computation?

CHENCHIAH: I've changed my mind since, but I think at that age I saw computations as being less pure, more a dirty hack. I've completely changed my mind on that now. [laughs] I'm somewhat embarrassed about that. It sounds very narrowminded, to be very honest with you.

ZIERLER: Maybe also computational capabilities when you were a grad student certainly aren't what they are now, and what you can accomplish wasn't nearly as profound. I wonder if that's part of it.

CHENCHIAH: No. [laughs] I wish I could say yes, but no. [laughs] It was entirely unawareness of what those computations could open, and I think I had a certain purist mindset in a very negative sense of purist. I have learned from that. If I could go back, I would educate myself more broadly.

ZIERLER: You've laid out the problem that Kaushik presented to you. How did you work through it? What did that look like?

CHENCHIAH: It involved reading up on some existing work on it. I was trying to understand the continuum energy of a two-phase elastic material under some conditions. A well-known researcher, Robert Kohn, at New York University—he's still there—had solved this problem with some restrictions. He had to make some assumptions on what the two phases would look like. I wanted to generalize the problem and look at it with fewer restrictions. The first step was to read his work carefully and then read more broadly and then ask what we could do that would push the problem to beyond what hadbeen done so far.

ZIERLER: I know it is going to foreshadow—you did not get interested in biology until later on—did you interact with Mory Gharib at all? Did you take any sort of inspiration from what he was doing in biomimicry?

CHENCHIAH: Not at the time, no. I had classmates who worked with him, so I definitely knew about him, but no, I didn't.

ZIERLER: Another foreshadowing question based on your interests in aerospace engineering—did you spend time at JPL or did you work in GALCIT at all?

CHENCHIAH: I certainly took classes with people from GALCIT. I already mentioned Ares Rosakis who was there, and Michael Ortiz, who I interacted with a fair amount. And Wolfgang Knauss, who has since retired. I should also mention Guruswami Ravichandran.

ZIERLER: Yes. He is now leading a new research institute called the Jio Institute in India. [laughs] I don't want to speak on behalf of Caltech, but the sense is that everybody wishes him well and that it's a great success but also that he comes back, so it's sort of a split hope for Ravi. [laughs] What were the findings of your thesis? What were your conclusions?

CHENCHIAH: They came in two parts. In part one, I was able to substantially generalize the earlier work on two-phase materials. We now had an almost complete account of how they behave, again in certain settings. That's part one. Part two was looking at polycrystals. This is when you take this material and it is no longer one slab but many slabs put together, and what happens then. I was looking at some of that as well. This is how the thesis splits into two parts.

ZIERLER: Of course with a thesis, ideally there is a duality—there's the narrowly conceived research question and then the broader implications as they relate to engineering and science. Looking back, what do you see as those broader implications? What is the bigger picture there?

CHENCHIAH: Some things I was too young to see then, but looking back now, if you look at materials, in some sense you need to tame the complexity and the diversity of possible behavior. What you need is some kind of a taxonomy, not just in naming but also in understanding the various kinds of behavior that can go on. I think part two of my thesis that showed that polycrystalline behavior could be quite complicated. With mature eyes looking back, I would say it was a window into the need to understand how to tame this jungle. Now, I shouldn't make it appear as if no one has seen this before. I think plenty of other people saw this even back then. But it took me some time to look at that. It is something like learning a new language. I think something of this sort is what I was groping towards without being enlightened enough to see at that time.

The Postdoctoral Pull to Europe

ZIERLER: When it came time to defend and thinking about next steps, what did you want to do? Were you looking at postdocs and faculty positions at the same time? Did you want to stay in the United States? Did you ever think about returning to India?

CHENCHIAH: I wanted to stay on in the Western world but I was very conscious that I had only seen one small part of it. I wanted to see the rest of the Western world, which is why I decided to move on to Europe. I think at this time I was becoming very aware and conscious of a certain hole in my intellectual life, that I wasn't well educated in a great tradition, neither Indian nor Western, and I was looking to immerse myself more deeply into Western culture. That was a very strong personal motivation. I thought that could be better done in Europe, not because the U.S. doesn't have a strong tradition of the Western culture, but because I thought if I did it in Europe, I would see more of the Western world. That was one strong personal motivation. Also, I wanted to move further away from engineering and more into mathematics. I would say I have since made a return journey, but that was what I thought I wanted to do then.

ZIERLER: What was it about your graduate experience that inspired you to become more focused in mathematics? What did you want to gain with this expertise?

CHENCHIAH: First I realized that I didn't have enough of the mathematical tools or expertise I would need in order to progress my scientific vision. For example, going back to taming complexity, one needs the appropriate mathematical tools, and I had only just begun to learn them. I thought a much more mathematical postdoc position would help me do that. It's also about the environment you are in. One learns how to think in a certain way by being with people who think in that way. Simply being in a more math-focused institute, I hoped—and it did succeed—would enable me to ask different kinds of questions, to look at the same problem with different eyes. I would say in both culture and mathematics and science, I am a strong believer that true learning is interpersonal. I see books, websites, other recording, media, as somehow extensions of the human persons, and that you truly learn by person-to-person contact. There's a kind of learning that can never entirely happen only through reading a book. So, I wanted to be surrounded by mathematicians, and this is also what drew me to a postdoc position in a mathematical institute.

ZIERLER: This also of course is a Jewish concept, the importance of learning person to person, which can create far more than learning between yourself and a book.

CHENCHIAH: Absolutely, absolutely. It is also—not to take away from Judaism, but to complement that—it's an idea that's very strongly found in Plato, especially in the dialogue Phaedrus, where actually Socrates says that true communication occurs only person to person.

ZIERLER: It's the dialogues and not the monologues, of course. [laughs] Based on your interest in broadening your knowledge and expertise in mathematics, it sounds like the Max Planck Institute for Mathematics and the Sciences was really the perfect place for you.

CHENCHIAH: It was an excellent environment. I learned a lot. I think it's fair to say that when I was there, I did not take full advantage of it, but what I learned there and the people I met there, I could go back to later in life and more fully develop ideas and themes.

ZIERLER: What was the overall research culture like at the Max Planck?

CHENCHIAH: I would say there was a lot of freedom. I didn't have a set project to work on. I was given a stipend and I was told I could do whatever I wanted to. So, an immense amount of freedom. Very intellectually stimulating. There were regular weekly seminars of different kinds, very frequently workshops organized, a generous travel budget so I could go to conferences, workshops, et cetera. I would say absolutely no administrative workload. In fact, the Institute staff even took care of my legal responsibilities, like registering with the town council and things like that. It was a very idyllic time, actually.

ZIERLER: Did you take formal classes in mathematics or how did you get better at math during your postdoc?

CHENCHIAH: Simply talking to people, studying on my own, and working on problems. I sat in on a few lectures as well.

ZIERLER: What were your research projects as a postdoc? What did you focus on?

CHENCHIAH: On one hand, I tried to continue working on what I was already trained in, which is multiphase materials, but that is also the place where I first encountered biology, although maybe at a remove, so not directly speaking with biologists. Although there was a mathematical biologist there, Angela Stevens, whom I discussed ideas with. But the awareness that there's an entire world of biology out there, which was intriguing and investigable, I first took it seriously when I was at the Max Planck Institute. I would say that endeavor didn't bear fruit immediately—it took several years—but that's where the seeds were sown.

ZIERLER: Your cultural ambitions to spend time in Europe, were they met? Was that meaningful for you to be in Europe?

CHENCHIAH: Very much. When I left the United States, I realized I had made the mistake of not traveling very much in the United States. I actively set about to not make the same mistake again, so I traveled extensively in Europe and learned a lot. I've been to very many countries. In Germany, I tried to grow my musical education, so just listening to Western classical music. Bach was a natural because he had been in Leipzig. I tried to expose myself to European architecture. I was raised Protestant but I had become Catholic during my years in Caltech, but not long before I left, maybe a year before I left. So, it was also a time when I began to read more about Catholicism, and I think a lot of authors I read were European, so that indirectly put European culture in there as well.

ZIERLER: What prompted your interest and move into Catholicism?

CHENCHIAH: Ah, difficult to summarize. Maybe I can pick up on just one strand. I think it was trying to understand the conceptual foundations of Christianity and searching for an intellectually rigorous and coherent Christian tradition. I don't want to come across as saying that is not part of Protestant Christianity. I have an honest respect for the religion in which I was raised, and it is Christianity too. But somehow trying to maybe take a step back from the religion in which I was raised and looking at it with more detachment and maybe a more critical gaze, not critical in a negative sense but critical sense of better understanding, led me to Catholicism. I think again this is the kind of similarity with my scientific work as well, where one tries to stand apart from an object and look at it.

ZIERLER: Then, your growing interest in Judaism, did that happen during your time in Europe, or that came later?

CHENCHIAH: It was during my time in Europe, yes, but not in Germany. That happened much later when I was already living in the U.K.

ZIERLER: When did you feel ready to go on the job market? When did you feel like you were ready to take on a faculty position?

CHENCHIAH: I would say never. In fact I don't feel ready even now.

ZIERLER: [laughs]

CHENCHIAH: I think what I learned was that one ought not to take these feelings of not feeling ready very seriously, and it's a lesson I continue to keep learning. "Start before you feel at ease" has now become my motto.

ZIERLER: Was your first position at Bristol? Is that where you have been since?

CHENCHIAH: Yes. I was very lucky, looking back. I interviewed for one position and I received a job offer and I accepted it. So, I do not have much experience looking for jobs! I interviewed at one place and that became my academic home.

A Mathematical Mindset for Interdisciplinarity

ZIERLER: You already emphasized the strong tradition of interdisciplinarity at Bristol. Was that an attraction to you? Did you see that this would be a place where you could expand yet into further disciplines?

CHENCHIAH: I wasn't aware of that aspect of Bristol before I joined. What I did notice was that I would be a new direction for the department. At that time there wasn't anyone doing the kind of work I was doing at Bristol Mathematics. To some extent, it's still true that there isn't anyone else. So, I was aware that I would be forced to go out and talk to people doing different things and build bridges and open myself up intellectually to new things. I think that was an attraction.

ZIERLER: What was the connecting point to biology? How did that start?

CHENCHIAH: Bristol has this tradition of organizing events where people from different disciplines are brought together, locked up, so to speak, in a room and forced to talk to each other. These are so-called, for example, speed dating events. I used to attend several of these events where complete strangers come together and each person says, "This is what I do." Then you are given a glass of wine and asked to go out and find a common problem or common interest. I took part in many of these events. I met a plant biologist, Claire Grierson, at one of these events, and eventually went on to work with her. I met another biologist Daniel Robert with whom I worked on bees subsequently. I think Bristol certainly provided the space and the infrastructure to do these things.

ZIERLER: How important was it for you to have that mathematics background that you gained as a postdoc as an entrée point to biology?

CHENCHIAH: It's actually I think a mindset. People can look at mathematics as a tool, basically as a manual of calculations that you could use to achieve something. The idea here is that I go to the grocery store and I buy some apples, some oranges, and I want to know how much to pay the grocer. That's one way of looking at mathematics. I think that's the common way; you associate mathematics with calculations. But the more honest view of mathematics, honest from within the discipline, is to see it as a way of looking at the world, as understanding mathematical objects, what they are, how they behave, and then how they could map onto other things like physics, biology, et cetera. I think this critical shift happened during my postdoctoral years. At Caltech I think I learned to use mathematical tools, and in my postdoc I realized, no, it's actually a bit more than that. You have to expand your mind to see the world with different eyes. Now, in a biological problem, you could try to set up a problem and then use some well-known mathematical tools to solve the problem, but the deeper work is to learn enough of the biology so that with mathematical eyes you can try to see, okay, I see these objects there, and this thing interacts with this in that way, so here a mathematical structure somehow comes out of it. This difference of visions I think I learned during my postdoc years.

ZIERLER: I'm curious about the expectations of junior faculty in the U.K. Obviously I'm most familiar with the American model, where junior faculty are expected to basically win funding grants and be able to support graduate students and keep a lab running. Is it mostly the same in the U.K.?

CHENCHIAH: It could depend on the discipline. I was treated very generously. I was given time to explore new things and learn at my own pace. I must admit I'm a fairly slow learner, I think it's fair to say, and Bristol gave me the time to learn more slowly but hopefully learn better and produce fruit in good time. For me, it has been a great environment. It's probably unusual. I think many other people are in more pressured environments.

ZIERLER: Because you waited, what did you publish on, and why did you feel ready at that point?

CHENCHIAH: I think there are maybe two or three markers of work that you think is ready to publish. One is when you think you have a fairly complete account without any loose strings. When I say, "without loose strings," I don't mean no further questions have been generated—any good research generates further questions—but without any gaps in what you are saying. I think that's one. Also, I think a completed piece of work has a certain sense of elegance which is difficult to define. If you can look at it and say, this is not incomplete, it's not taped together, it has some inner coherence to it. That's one. Ideally that will always be the case, but I think there are also cases sometimes when you say, I have some of the theory but there's this intractable obstacle I'm not able to make progress on after considerable time and effort, and then I will be honest about it and put this out there and point out that this is what this work says and here are the gaps that we have to still work on. I think there's a case for that as well.

One of the things that I have learned over time is when I was young I looked at each publication as a stand-alone item that had to stand on its own legs, and therefore I had a certain vision of elegance, as I've just articulated. But now I see individual publications as bricks in a larger structure. I don't ask of each single one of them that they should have everything I would like to say in a piece of scientific work, but I see them as contributing to the whole.

ZIERLER: You mentioned that you came back or you embraced computation in your faculty life. How did that happen? What inspired you to make the switch?

CHENCHIAH: Largely because there were problems where you had to ask yourself, "What happens if I do this?" but the "this" that you wanted to do was either difficult to do analytically or would take an inordinate amount of time. It is easy to do computation to either see if a certain idea was worth exploring or to say, "Actually, this is a dead end. This doesn't work." It began as a tool to prospect out interesting areas to go down and to shut down dead ends. That's how it began. Then of course once I allowed myself to do that, I slowly began to see that it's much more than that. You can change how you do science. For example, there have been people who have tried to understand if you can embed computations in let's say structures that change their shape so that the shape of the structure tells you something about its internal state and what it will do next. I think it's called morphological computing. You somehow try to not think of a control system and a structure as being two distinct things, but they both merge into each other. Ideas like this require one to be open to computation as not just a tool that you use but as telling you something more about the world around you.

Intellectual Maturity and Computational Embrace

ZIERLER: You emphasized earlier that your embrace of computation was really more about maturity and not about computational capabilities when you were a graduate student. How did that signify your academic maturation? Was it that you were asking more fundamental questions? Was it that you were more intellectually comfortable in a wider range of questions?

CHENCHIAH: I think definitely the latter, but also I began to realize that my earlier mindset was too narrow. I looked at the world with a too-narrow set of goggles. It's somewhat similar to someone looking at mathematics as just a calculation tool and then seeing mathematics as a conceptual, intellectual endeavor. I began to see that computations were not just about getting some calculations done but an entire way of looking at the world around you. I should clarify, though, that I still don't do computations myself. I think it would take a long time for me to invest in being able to do that. I just work with other people where we share the vision but someone else actually implements it.

ZIERLER: Is it also simply a matter of logistics, that your interest in biology wouldn't be nearly as impactful without computation?

CHENCHIAH: That's definitely true, but I am not so sure I was driven so much by that. I think what led me to change was seeing that the world was different from how I had perceived it earlier. But it's definitely right that it's difficult to make an impact if I didn't go down those paths.

ZIERLER: Either by a successful conference presentation or a paper or a research project, what was it that convinced you that this unique approach that you have where there's biology, there's computation, there's math, there's engineering—when did it all feel like it started to click for you?

CHENCHIAH: Difficult to say. Has it clicked yet? I don't know!

ZIERLER: For example, viral mechanics brings in all of those aspects. It's significant research. I wonder if that might indicate a clicking, if you will.

CHENCHIAH: Thank you, I think I understand the question now. I would say something that I really enjoy doing is—going from bacteriophage T4, and then I began to talk to some colleagues in engineering about, hey, why not take what this virus does and try to build a macroscopic tool that can have two stable states? We did that. This is work from about 10 years ago. We could actually manufacture these objects. It's really nice to hold in your hand this cylindrical lattice that was inspired by this virus. Then we saw that we could tune them with much more freedom than the virus seems to exhibit. Then we saw that if we put a lot of them together, we could actually mimic arbitrary energy functions. What we were able to show is that I have a number of these essentially one-dimensional structures—they only contract or expand—and let's say I put them together as concentric helical lattices—and if I put them together in the right way, I can mimic to arbitrary accuracy any energy function that you give me. This is a result that I found really interesting and was very pleased by. It gave me a lot of intellectual joy. But it certainly wouldn't have happened without the PhD student we had doing the computations to show and validate that this is really happening, without the people in the lab actually building these structures and testing them and showing that actually they do work as we said they would work. That's I would say a nice trajectory. Recently we've been able to partially extend this to two-dimensional objects, so you can have a 2D material and with some restrictions, you give me the energy, and I can build a material that comes close to that energy. Not as nice as in 1D but it's a step forward into two dimensions.

ZIERLER: You mentioned the culture at Bristol was quite generous in giving you time to gain this expertise, to think through these problems. Was that reflected in the tenure clock? Was it reflected that at year five or six, you might not be as far along as if you were much more narrow in your focus?

CHENCHIAH: Definitely. I joined Bristol in 2006 and I was tenured in 2013, so that's seven years. I think that's longer than in an American university. I think that fits well with my style of working. Bristol was very generous in letting me have that time. It also gave me the chance not to just continue doing what I was good at because it's efficient, but take the time to invest in learning new things, where naturally I'm slower and more clumsy in the beginning.

ZIERLER: Either by giving a tenure talk or just in thinking about these things yourself, how did you sum up what you accomplished in those seven years?

CHENCHIAH: I would say I consolidated what I had learned at Caltech to take it on into new areas. I had a good grasp, I would say, of multiphase materials, in a way that I could now think of them in new contexts. One strand of my research now, for example, is trying to mimic in engineering structures what alloys that phase-transform do, so take mechanisms at the crystal lattice level and engineer them in structures that you actually design in the lab, design and build in your lab. I was able to study and understand solid mechanics at the level of expertise required to be able to translate this into a different domain. That was certainly one thing I achieved in the seven years. Also I learned enough biology to be able to get moving in a new direction. The effort it takes to talk to biologists and understand what are interesting questions where you think you can contribute and to convince them that you might have something to add to the work that they are doing.

ZIERLER: Clearly you were not scared to go in new research directions even as an assistant professor, but having the security of tenure, did that allow you to pursue things that you might not otherwise have?

CHENCHIAH: Absolutely, yes. In fact, one of the first things I did when I got tenure was to decide to spend some more years studying biology. I actually [laughs] completely exploited the freedom to sit and learn a lot more biology than I knew earlier. Earlier, a lot of my studies were on either these viruses that I was interested in or on the mechanics of growing objects, but after tenure I expanded to learn more about plant biology, and eventually it led to electroreception—although that came a few years later—and also to look at tissue mechanics, which eventually led to working on wound healing. I definitely decided to continue doing what had worked well in the past [laughs], in the sense of investing time in studying and learning about new things. I think also it just gave me the sense that this approach of taking time out to learn new things is a worthwhile way to do science, even though one has to be patient and wait for the results to show. It doesn't fit very well with the quick and short time scale of academia these days. It is more, I would say, a throwback to an older era of doing science. I'm not sure. You're the historian so maybe you can help me out here.

ZIERLER: I don't know if I can! [laughs] Thinking about wound treatment, for example, is that to say that even though, as you emphasized earlier, your interests are really curiosity-driven, has your research had translational or even clinical applications in biology?

Research and Responsibility

CHENCHIAH: Not at the moment. Wound healing, no. It would be dishonest to say that it has led to applications. But I think we are making progress with that as a long-term goal, and fingers crossed that what we do genuinely would benefit humanity in a very direct sense. Similarly with my work on bees, as you are likely aware, bee populations have been falling quite rapidly around the world. Bees play a large part in human food security because pollinators are really needed for us to grow crops that we all eat. I am hoping that the work we do on electroreception and that we're trying to do on electrical ecology will help us understand how the world looks like to a bee, especially the parts of the world that the bee can see that we can't. I'm using "see" as a metaphor. Bees can sense electric fields. So, the world looks very different to a bee than it does to us, and if you can get some sense of what the world looks like to a bee, then we might be able to understand better why our bee populations are falling, how can we help bees live better, and that has consequences for humanity as well. A happier bee is a more bountiful harvest for us.

A question of this kind or a goal of this kind is for a lifetime. I definitely want to go in that direction but it's nothing that can be achieved, I would say, in one, two, or even maybe ten years. One more Jewish saying, it goes something like, "You will not complete the work in your lifetime but you are not free to walk away from it." I'm mangling this quote, but the sense that a worthy goal takes generations to achieve, and just because it's beyond your lifetime or beyond your research career doesn't mean it's not a good question. But also if people are only doing work that they can see the immediate benefit of, then a lot of good work will not be done.

ZIERLER: Perhaps you've come across the Hebrew word chiyuv?

CHENCHIAH: No, I haven't.

ZIERLER: A chiyuv is a responsibility, a halachic—a biblical responsibility—that you're obligated to do something. The phrase that you mentioned is exactly that, that one has a personal obligation but that personal obligation should never feel so crushing that it's entirely on your shoulders. You have an obligation to contribute but the obligation is not yours alone. Isaac, the question of trying to see the world through the perspective of a bee clearly has philosophical implications. How do we know, ever, what a bee sees? We can't ask a bee. How do you get around that? How do you make that a meaningful research question with the obvious intellectual limitations that are part of it?

CHENCHIAH: That's a really good question. Imagine you bump into this new creature you've never seen before. You're going to ask yourself a very simple question: can this creature see? I'm using "see" in the very normal sense of the world, as we human beings see. There are two ways to approach this question. One is to examine this creature and to see if it has something that looks like an eye on it. Another way of approaching this is to expose this creature to different lit environments and see how it responds to light. These are two very different ways of answering the question. The first method, you presuppose that there is a certain way of sensing light that you already are familiar with from your own experience as a human being and you look and see whether the bee has that apparatus, an eye. But a second—it's a more general approach—you don't a priori assume that there's only one way of seeing, but I identify something about sight, it is a response to light. Without any presuppositions about how an animal might or might not do that, you just ask about its behavior. I ask myself, this creature, I'm going to turn the light on and turn the light off, and do I see any difference? If one side of the room is lit does it want to go towards it, or away from it, or maybe there's no change?

So, when I say, "understand how the world looks to a bee," ultimately we would want to be able to understand bee behavior. That's where I'm coming from. It's bee behavioral psychology, so to speak. Now, to do that, we do need to understand something about its sensory capabilities. If bees can sense electric fields, and that plays a large role in how they respond to world around them, we can't understand bee behavior if we don't somehow encode that in our models. But I wouldn't claim that at the end of this I would know what it is like to be a bee. There's a famous paper by Thomas Nagel, "What is it like to be a bat?". He is trying to make the point that you can't do that. You don't know what it's like to be a bat, or a bee. But you might be able to understand how a bee would predict in a certain situation, at least probabilistically. So, I would say in terms of bee psychology, it's an entirely behavioralist approach.

ZIERLER: Perhaps this is an obvious assumption, but is the universality of math really so truly universal that it can transcend the obvious communication barriers to understand the perspective of non-humans?

CHENCHIAH: Ah! I don't know if I have the expertise to answer this question. It certainly is worth a try, I would say. You're asking me questions that go far out of my expertise. I don't know. But if anything can be a candidate, it's probably mathematics.

ZIERLER: A more prosaic question, moving closer to the present—when COVID hit, given your interest in viruses, did you study COVID at all? Was that an opportunity for you?

CHENCHIAH: Unfortunately, no, largely because at that time I had an administrative role. I was Senior Tutor for the School of Maths, and part of my responsibilities--- working with a team---was to ensure the emotional well-being of undergraduate students. A lot of them really struggled with COVID. This was already a heavy responsibility, but when COVID came it became pretty much all-consuming. Apart from graduate PhD students and working with postdocs, all my time was spent ensuring that the undergraduate students were doing as well as they could, given the situation. It wasn't a time for me to begin a new research project or even to work much on existing research projects. I must say COVID was largely spent serving the community rather than furthering research goals.

ZIERLER: This is very important work. Graduate students faced enormous psychological difficulties as a result of the isolation. This was a tragedy for them. This was a time to be in a lab, interacting with your fellow students, and an entire academic generation was mostly robbed of that experience.

CHENCHIAH: Absolutely. I did learn something valuable from that, which is that I noticed that if you compare an undergraduate student population with faculty, I get the sense that the faculty are more introverted in general than the student population. I think a lot of people systematically underestimated how much a lockdown would hurt people simply because they were the kind of people who happily spend 20 hours a day by themselves. I am largely introverted. I do enjoy human company, but I'm also happy to be alone by myself, so I think the lockdown aspect didn't hurt me that much. I was not happy to be in one room all day, but not being able to go to a pub or a disco was fine. I don't do those anyway. [laughs] A lot of other people are not like that. For them, human contact plays an immensely important role in their life. I think once again it showed me that my vision of the world was too limited. I was not sufficiently aware of the range of human personalities and the importance of being sure a policy fits many different kinds of people and not just one or two.

ZIERLER: Moving the conversation right to the present, do you retain these administrative responsibilities or are you back to the research now?

CHENCHIAH: I'm back to research now. I stepped down a few months ago, at the end of the last academic year, and I have a sabbatical this year partially in acknowledgement of the fact that that was a heavy responsibility for several years. This year I am entirely focused on learning new things and research.

ZIERLER: Intellectual recovery mode for you.

CHENCHIAH: Exactly.

ZIERLER: What are you working on? As a snapshot in time, what's interesting to you?

CHENCHIAH: I'm actually in Cambridge at the moment. I have been here for three weeks—I'm here for one more week—participating in a program on statistical mechanics in biological systems. This brings together my interest in biology, but it also gives me an opportunity to learn statistical mechanics, or statistical physics more broadly, which is something I'm new to. It's great to walk up to someone who is 20 years younger and say, "You are an expert in this field. I know nothing. Teach me about what you are doing." I really enjoy that. So, I've been trying to increase my knowledge of physics. I've had a very surprising discovery that a problem I've been working on, on morphing structures, seems in the eyes of the people around me to have interesting implications for viruses again, which I wasn't thinking of at all. It looks like I was trying to build structures that have multiple states, and here people are telling me, "Hey, that looks like something viruses do." So it has been really interesting talking to them.

Caltech and the Respect for the Individual

ZIERLER: For the last part of our talk, I'd like to ask a few retrospective questions about your career, and then we'll end looking to the future. Of course what brings us together is Caltech. What has stayed with you from your Caltech experience? As you approach science, engineering, math, as you learn to work with colleagues, what are some Caltech values that still inform your work as a scholar?

CHENCHIAH: I would say the importance of a welcoming, warm environment. I don't see how I could have been better taken care of as a graduate student than Caltech did, right from the first day I arrived until the day I graduated. Really simple things like the international students office fed us for an entire week because they didn't think the person fresh off the—I was going to say boat, but plane—from India would be able to go and buy groceries and start cooking. A very small thing, but very thoughtful. When I graduated, Caltech organized for my thesis to be proofread. This is, again, a really small thing but shows the thoughtfulness that entered into it. I have always taken away from there the importance of making sure the—researchers are human beings, and to make sure that your institute or your group is a place where humans working as scientists can flourish. That's a value I have really taken away.

The other thing which I think I really learned from Caltech—more specifically my PhD advisor Kaushik Bhattacharya—is to respect the personality of each individual student. Something I noticed Kaushik doing was he didn't give all his PhD students the same kinds of problems. He asked, "What would you like to do?" He tried to understand what your personality strengths were and what kind of science excites you and give you a research problem that fit with that. That's something that's really made a deep impression on me, to look at every individual student or postdoc as a unique human being and try to adapt to this person, I would say in the same way that it's the responsibility of a parent to discern their child's personality and adapt a parenting style that suits that child. I can't resist—you can delete this later—I can't resist a comment here. There's—maybe midrash is not the right word—one of the commentaries on why Esau went bad, which is the traditional Jewish reading of Esau, is that Isaac and Rebecca did not pay sufficient attention to his personality and tried to bring both him and Jacob up in the same way. What they should have done is given them both very different upbringings that would have been uniquely suited to them. [laughs] You can delete that for later!

ZIERLER: No, that's great. That's a classic observation. Jacob and Esau, or Yaacov and Esav, they could not be two more different people. That's very well established.

CHENCHIAH: I really should thank Kaushik for this. I have never told him this, and maybe this is an opportunity for me to email him and tell him this. I saw him do this, and I've learned that from him. The last thing I would say is, again I should thank Kaushik for this, goals and time pressures certainly have a role to play, but there's also a place where you tell your students, your postdocs, "Here is this box of Lego. Go play with it and come up with something that you like." As a young graduate student, I was given the freedom to take my time to work on a problem, go off for two weeks and read something interesting, and come back and say, "Actually, these two weeks, I have made no progress on the research problem because I read this interesting paper instead." A certain sense of not constantly checking on people to see what progress have you made in the last week, and give people time flexibility. Again, I thank Kaushik for this, but I think Caltech actually fostered this. Looking around at my fellow graduate students, I didn't get the sense that we were so stressed about meeting goals or deadlines that we couldn't think creatively.

ZIERLER: As you well know, in academia, there are so many external signs of progress—having a conference proposal accepted, getting a good review in a paper, achieving tenure. If you can wipe all of that away and reflect on what you've done, internally, how do you know that you've accomplished something significant? Especially because your research agenda is so varied and it's so unique, how do you access its own significance, both in terms of establishing the importance of following your own curiosity but perhaps even ultimately making these discoveries relevant in the real world?

CHENCHIAH: I think the criterion I would look for in myself—and by the way, I have not achieved this yet, so I have not succeeded, by my own criterion—is have you left behind other people, not necessarily your own students or postdocs, but other people in the community, who have taken on your ideas and taken them further. I think you know you made an enduring contribution if some insight, approach, method—whatever word you want to use—of yours has been taken up by other people, found to be useful and valuable, and then taken further. So I would ask for, what is your legacy, not in the sense of what papers did you publish, but where have your ideas entered into the community and taken on a life of their own, or taken on other forms of life. If one has done that, then I think one has made a contribution to the community.

Now, this might happen within a few years, or this might happen later on, and there are people for whom this has happened only many years, even centuries, after their death, that we have gone back to—this happens actually in humanities, that someone's idea from the thirteenth century suddenly takes on new life in the twentieth century. This is not to say that you cannot ever judge anyone until 500 years have passed.

ZIERLER: I hope not! [laughs]

CHENCHIAH: [laughs] But I think the thing to look at is not so much what have you done yourself, but how has your work lived on in others, other research communities, other research areas, other problems that you didn't work on but where your ideas were fruitful. That's the kind of metric I would propose.

ZIERLER: Last question, looking to the future. If the three major disciplines in which you're now comfortable and operate in, if there's a building block where we can associate one to your educational trajectory—engineering from IIT and then to Caltech, mathematics at the Max Planck, and biology now with Bristol—what's next for you? What's the new discipline or the new frontier of knowledge as you look to the next phase of your career? And is there opportunity to infuse spirituality, which of course is an interest of yours? Can that be a more prominent part of your research going forward?

CHENCHIAH: The answers might disappoint, I fear. I would say at the moment I am looking to consolidate rather than expand into new areas. What I would like to do is more tightly integrate already the existing trajectory of the work on mathematics, engineering, biology. So, I wouldn't say I'm looking for the next thing. That might happen in maybe 10, 15, years.

ZIERLER: Organically.

CHENCHIAH: Exactly. But I feel myself to be in a consolidation and development stage, where I've identified what I want to bring together and I'm going to work on bringing them together. Now, spirituality is a more difficult question. I have a hope that I could contribute to better friendship between Christians and Jews—I am actually working on a book project in private that I hope will contribute to that—but I think that's quite distinct from anything I do as a scientist. What I would appeal to scientists to do is not to dismiss religion a priori but to recognize that it's an interesting human phenomenon that is not likely to go away anytime soon, and to see if they can try to understand it rather than dismiss it. This is what I would propose to a scientist who can't be bothered with religion or spirituality.

ZIERLER: Just as an addendum, your desire, as you call it, to consolidate, is that because you've reached a level of comfort with these disciplines where simply the time has come to concentrate more specifically in the best possible way that you can answer questions that require such concentration?

CHENCHIAH: Actually it's the other way around. Let me try to give you an analogy. Imagine there's a work of poetry that you really like very much in a certain language and you want to make it more available to the outside world, so you've learned a second language. But you haven't yet translated the poem. You've just done the background work. That's how I feel now. I've put in effort to learn some minimal amount of biology. I have some vision of how we can bring morphing structures and mathematics together, but I think a lot of it still needs to be done. I see my career until now as a preparation for the thing I really want to do, and that's why I want to focus on that for the next decade or so. If that's done, then some new idea may come up.

ZIERLER: I'll check back in a decade. We'll see what progress you've made.

CHENCHIAH: [laughs] Thank you, David.

ZIERLER: Isaac, this has been a wonderful conversation. I want to thank you so much for spending the time.

[END]