Dr Pervez Amirali Hoodbhoy is a nuclear physicist, mathematician, and activist. He did his BSc in mathematics and electrical engineering from MIT and went on to have an MSc in Solid State Physics and a PhD in Nuclear Physics from the same institution. He has had an extensive academic career: working as a guest scientist at the International Center for Theoretical Physics (ICTP) alongside Dr Abdus Salam; professorship and research position at various Pakistani and American institutions like Massachusetts Institute of Technology, Carnegie Mellon University, Quaid-e-Azam University and the University of Maryland.

Dr Hoodbhoy has received numerous awards in recognition of his scientific research and science and educational activism, including Baker Prize, ROCASA Prize, and UNESCO Kalinga Prize. Moreover, he received an honorary doctorate of law from the University of British Columbia in 2019 for his services in promoting nuclear non-proliferation. He is currently a distinguished professor of physics and mathematics at Forman Christian College, Lahore.

Spectra sat down with Dr Hoodbhoy to discuss his ideas about scientific knowledge and the prospects of science education and science communication in Pakistan.

In the first of the two parts of the interview, Dr Hoodbhoy shares his deep insight on various scientific topics.

Image courtesy: Dr Hoodbhoy

You started with an engineering degree and later pursued physics. What inspired this switch of fields?

I find the theoretical side of science more interesting and challenging than its applications. Take physics – covers everything in the world. From subatomic entities much smaller than the atom to the atom itself, molecules, DNA, and the universe as a whole – everything is governed by physical laws. Physics is now so broad that absolutely nothing escapes it. So, I reasoned to myself that if I can know about something so grand, why then should I confine myself to some narrow application which will make a profit for some multinational company and its fat cat shareholders? I have only one life and I would like to live it the way I want to. Physics has kept me engaged all these years. And if I had another life, I would still be doing physics.

Recently, we have had a lot of people who had been doing engineering and were drawn to physics. We’ve already seen this overlap between chemistry and physics in the twentieth century. Do you think in this era, when physics is more applied, there is an overlap between physics and engineering?

Of course, there’s a huge amount of overlap because physics is the basis of everything. Physics and math were the very basis of the Scientific Revolution of the 16th century. However, physics has gone off in many different directions. On one hand, it is looking at problems like black holes, the origin of the universe, and fundamental particles. And, on the other hand, it studies the properties of matter in a variety of situations and their engineering for specific purposes.

In this world, you could say that everything is physics.

However, which aspect of physics is to be studied most intensively depends upon who’s paying for it and what use will be made of it.

I don’t think you can separate chemistry from physics. And with time more and more biology is coming in the physical realm. Consider the DNA molecule: it’s the very basis of life. The substitution of its different segments has to consider the energy of how molecules are locked together. So, physics has an infinite amount of breadth. But for convenience, we break it into 500 other smaller sub-disciplines.

Rutherford once said it’s either physics or stamp collecting. Do you agree with that?

If by stamp collecting Rutherford meant the categorization of raw data, it is very important indeed. In some situations, it’s only after a lot of data has been collected that one can arrive at what’s truly important. Take astronomy as an example. People have been looking at the skies for thousands of years, and they’ve been categorizing the sky. In observational astronomy, one separates out the brighter stars from the duller ones and categorizes them according to their mass and surface temperature. The next step is to explain why one sees certain patterns in the data. This leads to testable theories of star formation.

You’ve mentioned that physics has infinite breadth. Are there any limits? For instance, some people say that there is metaphysics. Is there any room for metaphysics in this world?

I don’t think metaphysics is of any use in the development of scientific thought. Metaphysics is of interest to those who want to speculate on what there is outside of the physical universe. Personally, I don’t think it helps us understand our physical universe – by which I mean that which is accessible to our senses and where we can test out things. There’s a lot of woolly stuff that people throw around and which they call metaphysics. Most of it is not worth paying any attention to.

What is the limit of physics itself?

Well, physics won’t tell you what the purpose of life is, whether there is one god or 5000 gods or no god at all, or if there is life after death. It deals with what is accessible to our senses, and that which is testable. Religions seek to explain why we are here and where we will go after this life. Take your pick from fifty different versions of religion but that is not the concern of physics.

But a person can ask why a law is the way it is and not in another way. Why can’t we describe the world in another way?

That’s because we make observations. On the basis of those observations, we deduce laws. Then, on the basis of those laws, we make predictions to see whether we have correctly deduced the laws of physics. And if our predictions match with observations and experiments, only then we are confident that our description is good. Otherwise, we keep searching for more accurate and wider-ranging laws.

If there are intelligent sentient beings elsewhere in the universe, then the laws they will have deduced cannot be different from the ones we have.

So, when you look at falling objects, you see ‘something’ is pulling them down. What is that thing? It turns out to be gravity. At a deeper level, as Einstein showed, gravity turns out to be the curvature of space and time. Space and time curve because of matter. So, in this way, we are able to understand gravity itself on the basis of mathematical principles and just a few suppositions. We make hypotheses and see how they work. We become confident in our understanding of the universe when we see that the hypotheses lead to correct results. Those who live a million light-years away cannot have a different understanding of gravity.

This is how the scientific method works. And it works not just for physics but for every area of physical science. It also works, even if partially, for the matters of society. Although social sciences are not predictive in the sense of physical sciences, you can understand a lot about society using the assumption that the world is understandable, and then trying to see what the laws behind it could be. This is how intelligent beings work.

So, humans are intelligent beings. How different are we from the other primates out there?

We are a highly evolved form of primates. We certainly have many of their negative characteristics such as territoriality – being possessive about land and fighting over it. Like primates, humans are programmed for aggression and competition. Those traits were essential for an animal to survive in the jungle. But humans have gone far beyond that in so many ways. Based on the principle of cooperation, we have learned to live together and form complex societies. Cooperation among animals cannot even be remotely compared to that among humans. Animals have only basic levels of communication.

For effective communication, one needs to have a language. Animals only have a very limited repertoire of expressions and don’t know about grammar or syntax. With grunts and groans and squeaks and chirps, they can convey some signals. Humans have highly sophisticated language skills, a result of our superior brains. Language is really why we can communicate and organize. Without this, there would obviously be no physics, no science, no civilization.

How does mathematics evolve?

Mathematics thrives in minds best capable of abstraction. We look at things around us and we deduce certain principles from them. Our experience then allows us to generalize it, and raise it to the level of an abstract principle. For example, I can add two apples to two apples and get four apples. I then see that whenever I add two things to two things, I always get four things. Thereafter we arrive at the abstract concept of numbers. Through a definite set of rules, we define the usual integers and then we go on to define other kinds of numbers including some pretty bizarre ones.

Mathematics is the creation of the human mind

For example, until 200 years ago there was no number around us that, when multiplied by itself, gave you minus one. So, someone invented the symbol called iota. By definition iota multiplied by itself gives you minus one. So, poof, a new kind of number entered our vocabulary! It turned out to be absolutely essential for solving certain equations that were otherwise unsolvable. That’s how we could solve what are called differential equations. Without iota, it would have been impossible to have predicted the existence of radio waves or to have understood their properties. The creation of new types of numbers doesn’t stop here. In seeking to understand elementary particles, people have invented numbers such that A times B is equal to minus B times A. Although such numbers don’t really exist, we force them to exist. They live only in our minds.

Quantum mechanics came in the twentieth century and it just turned our understanding of the world upside down. Do you think there will be another thing that would replace it? There are some people who are working on the foundations of quantum mechanics. According to them, quantum mechanics is incomplete, yet some say that quantum mechanics is wrong. How do you see that?

Quantum mechanics is most certainly not wrong. There is no physical theory that is wrong. It’s just that the gaps in our understanding will be filled with time. Newton’s laws were never wrong, but their domain of application was limited. Einstein extended the domain of understanding we had earlier to include particles moving close to the speed of light. It’s the same with gravity. Newtonian mechanics is not wrong; it is insufficient, incomplete and not fully satisfactory. Einstein gave a deeper basis for them. Returning to quantum mechanics, every single experiment done so far is consistent with quantum mechanics. So, even if there are some things about it that we find difficult to understand or believe, it cannot be wrong. 

No one doubts that quantum mechanics is puzzling. In fact, Einstein had realized it at a very early stage and had raised some pretty serious objections. He hoped that there were things called “hidden variables” that would be found one day. Then, in the 1960s, John Bell actually devised a test of quantum mechanics that eliminated that possibility. Einstein was actually wrong! There are indeed issues of interpreting quantum mechanics. For example, we still don’t know why the wavefunction suddenly collapses once you make a measurement. But these are the things that we will understand with time.

But for the unusual phenomena described by quantum mechanics, will there come a time when we will understand what is happening?

We will never fully understand it the way we understand falling rocks because we are macroscopic creatures and our daily observations are limited to a world where things are large. If we lived in a microscopic world nothing could stand still, not even a chair. Everything would be jiggling around and the world would lack complete certainty.

Understanding is a very subjective term.

So, we will never understand quantum mechanics in the way we understand our immediate physical world. However, our understanding is not limited anymore by what we simply see. Mathematics extends our brains to grasp that which is outside daily experiences. And I’m hopeful that we will have a very good mathematical understanding of everything related to quantum mechanics one day.

So, we’re driven by mathematics. What if mathematics is wrong?

Mathematics is built upon rules that we make, after which we draw logical deductions using these rules. As long as we stick by these rules and don’t make a mistake, math can’t be wrong. You can’t add two to two and not get four. It could be useless (a lot of math is useless) but it’s never wrong.

In this postmodern age, there’s a concept of reality, according to which whatever one says is their opinion. It’s like quoting the famous Marxist philosopher Althusser, who said that there is no such thing as reality and that reality is actually absurd. Where does science stands in this argument?

The postmodernists are reacting against the certainties of science, so you should take what they say with a pinch of salt. I am happy to listen to them on normative matters or in differing ways of understanding human society. Indeed, people from different cultures can look at the same society and arrive at totally different conclusions. However, when it comes to the natural world there is only one physics and only one set of principles governing atomic behavior. It’s then completely nonsensical to say that everything is relative. Relativism and postmodernism are fine when we deal with the matters of society, but not with matters of the physical universe.

You’ve mentioned that physical laws are more objective in contrast to social sciences. There’s an absoluteness in them as the laws aren’t something invented by men. Do you think that the binary logic of true and false is the only meaningful logic when it comes down to scientific studies?

It’s the same logic in the physical and the social sciences. However, societies are much more complex, and binaries don’t hold there. We cannot test laws in the same way. In fact, we don’t even know if laws exist at a level where predictions are possible. That’s probably because the number of variables is far too large. One may never be able to predict what an individual or a society does, except perhaps in some statistical sense.

Social science must content itself with investigating certain broad questions. For example, Marxism was an attempt to understand how societies moved from the pastoral stage to the feudal stage, then from feudal to capitalist, and from capitalist to socialist and communist. Similarly, in psychology, you can identify certain aspects of group psychology: people wanting to move together, people fearing that they would be ostracized or sidelined if they don’t move with the rest, etc.

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