Why is now not a good time to pursue theoretical physics?

This is a translation of a post I wrote in Spanish in 2017 in my old blog while I was doing my bachelors. I decided to translate it because I think it’s still relevant and I want to share it with a broader audience.

tl;dr

• The vast prerequisite knowledge for theoretical physics may soon exceed human learning capacity within a lifetime.
• The practical value of devoting one’s life to potentially unprovable theories, like string theory, is questionable.
• The future of theoretical physics could lie in artificial intelligence, rendering human study less effective. Thus, contributing to AI development may be more beneficial.

Before I begin, I would like to clarify some things about what I’m going to say:

The first thing is that I don’t have much knowledge of Theoretical Physics; I’m only in my third year of college (I haven’t even been studying Physics for three years yet), so I will probably make mistakes in many things and/or my thoughts may change in the future. However, I believe that my perspective can be interesting, especially for people who, like me, are considering their future in the world of physics. Therefore, my words should be taken with caution and considering that they are highly speculative.

The second thing is what I mean when I talk about Theoretical Physics. When I refer to Theoretical Physics, I mainly mean the following branches: Cosmology, String Theory or other attempts at unification theories, and Particle Physics. In other words, the more abstract and profound branches of physics. This does not include other branches, such as theoretical condensed matter physics.

In general, a person may have two reasons for pursuing a career in science. The first is the desire to contribute to the scientific and technological advancement of humanity, to improve people’s lives in general. The second is the sheer satisfaction of curiosity, what Richard Feynman called the joy of discovery. In my opinion, a scientist should possess both motivations, with the first one being more pragmatic and productive, although it doesn’t always lead to pleasant paths. The second one is more childish and selfish, yet we all need an incentive to help us not get lost on those devilish paths. Many times, by doing what we love, we achieve marvelous accomplishments. Therefore, I believe that a person dedicated to science should strike a balance between both motivations, avoiding getting lost in absurd digressions for personal satisfaction, but also not losing motivation due to the lack of satisfaction along the way.

I think we all agree that to be a theoretical physicist who makes a relevant contribution to the field, one needs to be extraordinarily intelligent. And as an intelligent person, one should be concerned with optimizing their work. Anyone who has delved a little into the world of research, not just in Theoretical Physics but in any minimally established field of knowledge, knows that the amount of information available is immeasurable. Until recently, the majority of the population did not have access to higher education, which meant that the few individuals who managed to excel in a field became known and had the opportunity to make great advances. Mind you, it doesn’t mean it was easy, nor that those individuals weren’t brilliant, because they were. However, we live in an era where more people inhabit the Earth, and a higher percentage of them have access to education that allows them to pursue higher studies.

Never before in the history of humanity have there been so many geniuses with access to education. However, you can grab anyone off the street and ask them about a famous scientist born after 1950, and most likely, nobody will be able to name one. And the reason is not because those people are ignorant, but because there are practically no famous scientists born after 1950.

This is not necessarily a bad thing. Currently, there are more scientists than ever before, and scientific and technological development is more accelerated than at any previous time, so it’s normal for an individual to find it more difficult to stand out. However, this overwhelming progress of science is making it increasingly difficult for a person to reach the frontier of knowledge. Let’s understand the frontier of knowledge as that point in a field where no one knows how to proceed further, and where the researcher must be at the cutting edge of science, forging a path through the darkness of ignorance.

For example, a person who wants to dedicate themselves to String Theory requires an enormous amount of study and hard work to truly engage in research in that field. They need to have a deep knowledge of Classical Physics, Analytical Mechanics, Quantum Mechanics, Particle Physics, Multilinear Algebra and Tensor Analysis, Calculus of Variations, Topology, Differential Geometry, Group Theory, General Relativity… In short, an endless list of things that you are obligated to know before being able to do something decent. The lifespan of a person dedicated to physics is about 50 years. From the age of 18, when the educational system allows them to fully devote themselves to Physics, until their retirement. Previously, 50 years was enough time to reach the frontier of knowledge and start doing new things. However, as science progresses, that time is becoming insufficient because there is always more to learn. Furthermore, every day new publications by physicists from around the world come out that you have to read (and understand) to stay up to date. In other words, more things that you have to study are being added while you are studying, at a faster pace than one can learn. This is the first problem that a student aspiring to pursue Theoretical Physics faces. If you want to contribute something (one of the motivations a scientist should have), you’re short on time. We are reaching a point where the duration of a human life will not be enough to conduct research.

The next question that a student aspiring to pursue Theoretical Physics should ask is: to what extent is it worth it? We have already mentioned that to pursue theoretical physics, one has to be very intelligent and work hard (and when I say hard, I mean really hard). Is this truly the best way for such an intelligent person to employ their time and intelligence? Let’s go back to the example of String Theory, perhaps the most illustrative one.

String Theory is a speculative theory about fundamental physics that aims to reconcile quantum mechanics with Einstein’s theory of gravity. It is a fascinating theory that has generated much fruitful research in fields ranging from pure mathematics to more mundane activities, such as simplifying routine calculations of cross-sections in particle physics. However, its characteristic predictions can only be tested if we have accelerators capable of reaching the Planck mass (more than 16 orders of magnitude more powerful than the LHC in Geneva); this is something that is currently unimaginable and not even feasible in the long term. The fact that it is practically impossible to empirically verify (a scientific theory must be falsifiable) leads to deep discussions among string theorists and physicists from other branches. In other words, what you’re dedicating your entire life to is probably nothing more than an extremely difficult puzzle that is empirically unverifiable and possibly false. Is it worth it? It all depends on which of the two motivations I mentioned earlier you gravitate towards. From a pragmatic perspective, it is highly likely that it’s not worth it. If we look at it from the standpoint of the joy of discovery, things might be different since there is an immense amount of information waiting to be discovered.

So, should human beings stop dedicating themselves to Theoretical Physics? From my point of view, yes, but with a catch. To explain my position, let’s remember the following proverb: “Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime.” Something similar will happen in scientific research, replacing fishing with computers. Artificial intelligence will arrive sooner or later (probably sooner than later, but definitely before humanity achieves an accelerator that confirms string theory), and when it does, human beings won’t be able to compete with a machine connected to the Internet with unimaginable processing and thinking capabilities. Perhaps the conclusions derived from all the work carried out by a theoretical physicist throughout their life will be accomplished by an artificial intelligence in just a few minutes. It will be absurd to do research just as it is now absurd to spend the night doing mathematics as the physicists of yesteryear did when the same mathematics is done with a line of Matlab code.

For these reasons, I consider that the field of Theoretical Physics is one of the most misguided places in which a person with a marvelous intelligence could dedicate himself, at least from the point of view of the pragmatic motivation of scientific activity.

What should a person who wants to contribute to the field of Theoretical Physics devote himself to? Well, to contribute to inventing the computers that will carry out such research. Right now there are a lot of lines open in artificial intelligence research, both in Software (Machine Learning) and in Hardware (Quantum Computing, neuroscience…). Who makes better use of his time? The one who builds a great scientific theory or the one who builds a machine that is able to create countless great scientific theories?