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Modern physics is in crisis, and Dr. David Lindley is here to explain how things got to be so confused. In The Dream Universe, How Fundamental Physics Lost Its Way, the esteemed writer traces the history of physics from the first locutions of the ancient greeks to professor Max Tegmark’s proposal that rather than living in a universe composed of material, we live in a world that is made of mathematics. 

The book is laid out simply - the first half explains the modes of thought that preceded Newton, through the material physics that persisted through the beginning of the industrial revolution. The second half of the book is where Lindley allows his presentation to unfurl. Somewhere during the last century of physics, the discipline was taken over by the mathematicians - and increasingly, it looks like they’ve painted themselves into a corner.

It’s important to note that this isn’t Lindley’s first time in the ring with theoretical physics. He got his Ph.D. in astrophysics from the University of Sussex in the 70s, then did postgraduate research at Cambridge and the Fermi National Accelerator. Following his tenure at Fermi he worked briefly at the Lawrence Livermore Laboratory and then as an editor at Nature, Science, and Science News. For the early part of his career, he was deeply engaged with theoretical physics at the highest level, and has come from the trenches to let us know what he learned there. 

He published his first book in 1993, the aptly titled The End of Physics. Rather than being a book about the inevitable approach of unification - the moment when a theory bridges quantum mechanics, Newtonian physics, and general relativity - this book was about how the prospects unification were dwindling because the physicists were no longer doing physics. 

It was written at a time where there were few people willing to openly confront the cosmological establishment. Popular interest in cosmology and theoretical physics was bolstered by a decade of public relations expansion. Stephen Weinberg’s The First Three Minutes was published in 1977, and provided a detailed blow-by-blow of the events during the first three minutes of the big bang. Carl Sagan’s 1980 television series Cosmos introduced a generation of viewers to general relativity and space exploration, sparking a love affair that continues to this day. Stephen Hawking’s A Brief History of Time, a lay-person introduction to string theory and the big bang, was released in 1988.  It was not a good time to be speaking out against the fundamental premise of these theories. 

And yet, Lindley did. He made the point that there had been a sea-change in the world of physics, a departure from the experimental to the theoretical, which had led to a terrible, unacknowledged crisis. Physicists, pursuing the beauty of mathematics at the cost of everything else, had ceded their relationship to reality. 

In this year’s The Dream Universe, Lindley continues to chip away at the central puzzle of how things came to be so abstract, so focused on mathematics, so ephemerally related to reality. The first half of the book is a history of physical thought, going back to the Ancient Greeks philosophers. He sets up a dichotomy between two schools of thought - the Platonists and the Aristotelians - that has persisted through the present day.

The Platonic school of thought positively disdained empirical investigation, saying that it detracted from the proper pursuit of philosophy, which was to figure out the nature of the universe through logic and reason. Theirs was the philosophy of the archetype, the contemplation of the ideal forms of nature, and the derivation of foundational principles from beautiful things. 

Aristotle, on the other hand, used reason in his own fashion. He believed firmly that the variety of animal life had its own logic. ‘Nature makes nothing in vain’ was his mantra. As he explored and documented the zoological world, he sought reasons for the way animals were, why they were made in such a manner, and how their form and structure were appropriate to their way of life.

For both of these schools of thought, reason and logic were prized over everything else, including the evidence of the senses. Reason was the way to establish fundamental truths and inescapable conclusions. Humans and their senses were fallible and untrustworthy.

The development of modern science, though, is an answer to the last point. Certainly our senses are fallible and untrustworthy, but there is a method, the Scientific Method, that can be applied so as to avoid the terrible pitfalls of our subjectivity and bias. The Method has proved itself to be the most effective tool that we have ever discovered for understanding how things work. In the two centuries since its invention, we have come to understand more about biology and chemistry than we have ever known throughout human history. 

We know how cells transmogrify sugar into fuel, how an animal develops from an embryo, the principle of contagion and disease, we are able to explain how diamonds form and volcanoes die. Through painstaking iteration, scientists have come to recognize that, despite the early accomplishments of the natural philosophers, contemplation alone cannot produce an effective outcome. In our modern practice of science we must closely examine a phenomenon, produce a working model for why it happens the way that it does, and then attempt to define the limits of the model. Once the limits are determined, this model can be applied more generally, and can be used as the basis for asking another question, one that gets us father down the line of understanding how things work. 

In fields like biology and chemistry, this approach has worked quite well. Science has progressed to the point that we are living in an era where the first gene-edited babies have been born, where CRISPR, a bacterial precursor to an immune system has been discovered, parameterized, and has been deployed to rewrite the genetic code of fully matured human beings. It’s hard to point to these fields as having run off the tracks, mostly because they have been so massively successful in both generating more complete understanding and in their ability to produce technologies that capitalize on the aforementioned understanding.

Much of this has to do with the fact that most fields operate on a level that is one step removed from the fundamental. As Lindley writes:

within any given discipline, certain facts and information are taken for granted. Oceanographers try to figure out how ocean currents flow, energized by solar heating and influenced by the earth’s rotation, but they don’t think about why the oceans have the shapes and sizes they do. Geologists studying continental drift try to understand how the oceans change over time, but they don’t give too much thought to the formation of the earth. Planetary astronomers want to know how our system formed, but they take the presence of interstellar gas and dust clouds as given. And so on. The vast majority of working scientists stay well away from the issues that concern the theorists of fundamental physics and cosmology.

It’s obvious, after many years in the lab, why most science works this way. The fundamental questions of physics and cosmology are unimaginably complex, and they don’t really affect the macro-scale phenomena that most of us study. The composition of the atom, or the evolution of the universe are considered to be of little importance to the direct questions that we ask in the laboratory or the field.

The problem arises when these fields nudge up against physics. Because our understanding of the atom has become so mathematical, so governed by equations and so distant from an material-based conceptualization, few researchers in other disciplines are brave enough to descend into the scrum. Instead, we defer to the physicist on faith that they understand, even when we don’t.

What keeps me up at night, though, is the central question at the heart of the Dream Universe. What if they don’t understand?

Beautiful Mathematics

At this point, Lindley is no longer alone, finger raised, mouth open, at the cusp of an objection against the fundamental premise that nature is governed primarily by beauty. Nor is he the only one suggesting that progressively more complicated mathematics are leading physicists away from actually understanding how things work. Sabine Hossenfelder, a Research Fellow at the Frankfurt Institute for Advanced Studies, recently released her book the subject, Lost in Math. Peter Woit, senior lecturer at the Columbia University Mathematics department, released Not Even Wrong 14 years ago. Lee Smolin, Faculty member at the Perimeter Institute for Theoretical Physics, published The Trouble With Physics in 2006, the same year that Woit’s book came out. There are others, too. Just spend some time looking around the internet, and you’ll find many others.

Lindley hones in on the invention of calculus as the first inkling of a shift in this direction. When calculus was invented, it was the first moment it became possible to replace calculation with explanation.  Calculation allowed the early scientists to replace physics with empirical knowledge, and measurement created a divide between those who contemplated, and those who calculated. The natural philosopher approach, a non-quantitative exploration of nature and how it behaved, was slowly supplanted by faith in mathematics. The “grand ideas” about the constitution of matter were allowed to fall by the wayside, replaced instead with complicated equations that said more about how a material was to behave, rather than an explanation of what was happening when the material behaved. 

One of the last old-style theorists in physics was Michael Faraday, who Lindley describes as a rare type, the nonmathematical theorizer. The largely self-taught son of a blacksmith, he made his name with artful experiments that isolated numerous aspects of the interactions between electric and magnetic phenomena. As a result, he came up with a unifying picture—I mean literally a picture, mental imagery that expressed this thinking—to tie all those phenomena together.

Faraday’s conceptualization of electromagnetic fields was stymied because he could not imagine the physical material that was responsible for them - but he never gave up his conviction that there was a material there, some kind of surface, that was responsible for the electromagnetic behavior that he measured in the lab. He was a scientist at heart, a man lost in the pursuit of understanding the process, rather than occupied solely with parameterization. Lindley contrasts the ephemeral treatment of Faraday’s electromagnetic fields with the staunchly Newtonian treatment given to the theory of heat, formulated by the 27-year-old Sadi Carnot in Reflections on the Motive Power of Fire, where he laid out the physical mechanics of molecules in motion that were the foundation of the heat engine. 

It is perhaps no surprise that this sea change in physics, a shift from physical explanations to physical parameterization came at the same time that the industrial revolution swept across the world. The old school of natural philosophy, founded on natural explanations for phenomena, could not fight against the tide. It became far more important, and perhaps even more fashionable, for scientists to produce rather than entrench themselves in theory. 

The back half of the book tracks the reverberation of this schism through the 20th century and into the present. There is Dirac’s mathematic prediction of antimatter, accidentally confirmed years later by an unrelated cloud-chamber study being done at the California Institute of Technology. Then there was Heisenberg’s use of matrix mathematics in his formulation of the uncertainty principle.

Mathematics continued to become the preferred tools through which physicists contemplated the universe, and conceptualization gradually faded into the background, fed by an obsessive conviction that not only is mathematics the language of the universe, but that nature speaks only in beautiful equations. This self-organizing principle, by which only those that are proficient and in love with mathematics can enter into the highest realms of theoretical physics, is what has led to the mathematical madness of the present day.

String theorists like Michio Kaku, Brian Greene, and Leonard Susskind are representative of the modern guard - individuals who fundamentally believe in the primacy of mathematics, of their ability to model the very universe itself with equations that are beautiful but have absolutely no relationship to the physical world that we inhabit. So deep is the divide, that there is no longer an expectation that the ideas in this research can be communicated to us non-mathematical individuals. 

Max Tegmark, author of Our Mathematical Universe, is perhaps the culmination of this perspective. He has produced a theory in which everything - atoms, electrons, galaxies, our bodies, all of it - is actually made of mathematics instead of material. It’s a project that he works on in his spare time from his full-time job as an MIT professor. He’s not alone in this, either. In his hour-long lecture at the Royal Academy of Science, the same room where Michael Faraday presented his findings on the relationship between electricity and Magnetism, Dr. David Tong explains that the idea that matter is made up out of materials is simply a white lie that we have been taught all of our lives, to spare us from the horrors of realizing the difficult to comprehend the truth. What is that truth, you may ask, that we have been protected from our entire lives?

It’s that the fundamental building blocks of nature are fluid-like substances which are spread throughout the entire universe and ripple in strange and interesting ways. That's the fundamental reality in which we live. These fluid-like substances we have a name for. We call them fields.

And lest you think that a field is a physical material, Dr. Tong continues. The physicist's definition of a field is the following. It's something that, as I said, is spread everywhere throughout the universe. It's something that takes a particular value at every point in space. And what's more, that value can change in time. So a good picture to have your mind is fluid, which ripples and sways throughout the universe.

What’s missing in this description, and missing in all of theoretical physics today, is a relationship to what, exactly, this is a field of. Even asking the question, because of these entrenched mathematical beliefs, is considered to be hopelessly naive. It is the kind of conviction in the primacy of mathematics that allows string theorist Leonard Susskind to report that he simply can’t explain the theory to a wider audience. They just have to take his word on it - the theory doesn’t work without six extra dimensions, and it must be left at that. 

What’s the point?

The point of all of this is to call attention to the fact that there has been a revolution in physics for the last century, one that has led to a massive division between those who understand the mathematics of the universe, and those who don’t. Like everything else in the contemporary era, this has all played out before. The divisions between the Platonists and the Aristotelians are playing out in our world, all over again - and the rest of the sciences suffer.

Physicists are the people that all others turn to in an attempt to understand the fundamentals. The rest of us hope that by turning towards them, we will find an objective scientist who we can trust to lead us in the right direction. What is alarming is that more and more voices are joining the chorus that suggests something has gone terribly wrong at the heart of physics. 

The future of humanity requires the disciplines of physics, biology, and chemistry to integrate with one another fluidly, to build a bridge between the physical world we inhabit and the quantum world that decides what the physical world looks like. 

Relying on the beauty of mathematics is a philosophical tradition that has been around for a long time - and has not managed to stand the test of time. The orbits fail to follow the geometric ideal of a circle, the universe stubbornly refuses to orbit around the earth, gravitation alone fails to explain the organization of matter through the cosmos. The kludges used in physics to shoehorn reality into the equations are reminiscent of mistakes that have been made throughout the history of science.

The only question that remains is how, exactly, do we extricate ourselves from this mess? David Lindley has some ideas. Read through The Dream Universe and see for yourself.