What exists?

A review of our quest to understand the universe and explain what it is made of.

4th Edition. Copyright © 2021 by David Stringer. https://www.eobar.org

(1st Edition published 2014)


The quest to understand the fundamental nature of the world around us has a long history. In modern times we tend to expect science to provide the answers. Before the 17th century, science as we know it did not exist and the quest was pursued by theologists and philosophers.

There is a little-known branch of modern philosophy that specializes in asking what really exists. Unlike ancient philosophers, these ontologists as they are called, have the benefit of science to guide them. Their knowledge and understanding of fundamental physics not only helps them seek answers but, perhaps more importantly, brings to light key questions that science itself cannot answer. They stand further back than scientists, so to speak, and therefore see the bigger picture. It is they who are most likely to come up with an explanation of what exists, even though it will be an answer that deals with fundamental science.

Before looking at the work of currently active ontologists, it is worth looking back to earlier philosophers and scientists who have influenced the quest. This review will help us get a feel for the obstacles that stand in the way of finding a satisfactory answer. One of the major obstacles, as will become clear, is that the scientific method, enormously successful though it is, is not well suited to painting the big picture that we so desire.

The scientific method

The scientific method tends to study nature from the bottom up. It gets down and dirty with the raw material of the universe. There is no theory of science nor law of physics that does not refer, even if indirectly, to raw data obtained from rigorous experiments. In terms of Plato's cave, we can think of science as the study of the shadows on the cave wall. Ontology, on the other hand, is the construction of a picture that we might see if we could look directly at whatever produces the shadows. Crucially, the picture must be one that would produce precisely the same data that science obtains. In Plato's allegory, the shadows were watched by prisoners who were prevented from seeing whatever produced the shadows. The allegory highlights the difficulty of studying nature. How do we know that what we measure and observe is real and not an effect or impression produced by something we cannot observe and measure.

Plato's cave: prisoners see only the shadows of reality
Image of Plato's cave

Illustrated by 4edges. License

The way that scientists go about a scientific investigation typically involves experiments. Data obtained from observations or measurements are analysed to find patterns of cause and effect. Hypotheses may be developed as potential explanations of the data. Further experiments may follow to test the hypotheses leading to a cycle of experiment-hypothesis-experiment-hypothesis. Finally, a series of investigations may result in the publication of a complete theory. A theory will show how experimental results back up a significant new understanding of a natural phenomenon and make predictions of the results of future experiments.

Science didn't really exist before the seventeenth century and even then, scientists were called "natural philosophers". Long before then, classical philosophers had some ideas about how nature works. In their universe, the Earth was at the centre and was made of four natural elements: earth, air, fire and water. Motion was thought to be due to elements tending towards their correct place. Air and fire want to go up; earth and water want to go down. Somehow things knew their rightful place and tried to get there.

Another concept that went along with active elements was Atomism. Things could always be divided into smaller and yet smaller things. It was supposed that there must be some point at which you arrive at whatever elements are made of, little bits of indivisible stuff moving through the void. The idea that nature is made of elementary material parts has persisted until this day. It is what philosophers call materialism but this term hides the very important notion that the material moves, changes and interacts in ordered ways. We still think that elements somehow have intrinsic behaviour built into their very being. Every particle obeys all the laws of physics. Stuff "knows" what to do and how to do it. It is strange, when you think about it, how glibly we accept that inanimate stuff is active material.

In the early 1600's, Sir Francis Bacon, the philosopher and statesman, established a scientific method with the rather arrogant aim of giving mankind dominion over nature. He put in writing a sort of recipe of how science ought to be done. Scientists who followed this method could all repeat and therefore check each other's work. The method required that data should be gathered directly from nature itself. Scientists' conclusions were to be drawn from actual observations and measurements. As a consequence, the importance of experiments with strict record keeping was established. The specifics of the scientific method have changed since Bacon's days but the principles are still those put forward by Sir Francis.

Bacon also brought the use of inductive reasoning to science. Ancient philosophers had used what is called ablative reasoning, essentially just intelligent guessing, which can only be tested by judging the strength of the argument. Inductive reasoning is a big step up from this. It is the drawing of general conclusions from a wide body of evidence. It is a bottom-up rationality: starting with what we can observe or measure, then seeking general principles that might explain what we discover. For example, if scientists find that gases expand when heated, they can propose the general conclusion that all gases expand when heated. This hypothesis can then be tested on all newly discovered gases. Inductive reasoning does not lead to cast iron proof because conflicting evidence may be found in future. But it does add weight-of-evidence to strength-of-argument as a test for the validity of scientific knowledge. By the way, Sir Francis Bacon had been Attorney General, Britain's chief law officer, so he was accustomed to accepting strong evidence as an alternative to proof. To summarise, the key features of the scientific method are repeatability, through a well-defined systematic method; empiricism through observation and measurement of nature itself; and inductive reasoning, which adds weight of evidence to strength of argument.

The scientific method turned out to be amazingly successful. Galileo, by making and using telescopes, started astronomy as we know it. He confirmed Copernicus's description of the heavens with the sun at the centre and the earth relegated to just another planet going around it. Galileo also made great advances in understanding how things move. Myth has it that he had two objects of different weight dropped from the leaning tower of Pisa. They both hit the ground at the same time, showing that gravity accelerates all objects at the same rate. Then there was Sir Isaac Newton's physics. Newton explained how and why things move using the concepts of mass, force and acceleration. For instance, he explained the motions of planets (and apples from trees) using gravity. Many other scientists, too many to mention here, developed new theories using the scientific method. The industrial revolution grew out of this success. The feeling began to grow that science had all the answers. Science seemed to indicate that we live in a universe that behaved like a machine. This period was known as the Age of Enlightenment because human reason replaced tradition and superstition as the source of knowledge.

David Hume, a Scottish philosopher, launched a strong attack on the scientific method. He recognized its success in describing how nature behaves but argued that many of its concepts should not be treated as true knowledge. Hume was very strict about what constitutes knowledge as opposed to belief. According to Hume, you can observe raw facts with your own senses and you can deduce facts using logic and mathematics. Everything else involves an element of belief. Every time science uses inductive reasoning to draw general conclusions from experiments, it is believing that the same experiments will always give the same results. It is believing that nature has a strict unchanging order of cause and effect. In short, inductive reasoning embodies beliefs about nature that may be wrong.

Hume also objected to science's use of man-made concepts in its theories. As an arch-empiricist he was deeply sceptical of anything that we cannot sense directly. Take, for example: energy, atoms and gravity. Hume accepts that these are useful metaphors for whatever really exists. Science needs to use such concepts in its mathematical book-keeping. But, according to Hume, we have no justification in taking them literally. They are human inventions, contrived to explain experimental data. There will be many different concepts that would also explain the data. We cannot know that we have found the correct concepts and the true explanations. We can only believe that we have.

Hume's scepticism seems pedantic. He implies that nothing less than perfect, logic-backed proof will do. Others pointed out just how successful the scientific method had been. Surely it would be a miracle if science had succeeded while being fundamentally wrong. Nature did seem to obey strict laws and be the same today as it was yesterday. But nobody could fault Hume's arguments so his attack carried weight.

Moving on to the 1800's, Auguste Comte, a French philosopher, rescued science from Hume's attack but only by diminishing the scope of science. He said that the scientific method was justified in explaining how nature works but it was not justified in drawing conclusions about what actually exists. Science goes too far, he claimed, and strays into metaphysics. Comte coined the term Positivism, derived from the French word for imposed, and expresses the idea that knowledge can only be imposed on the mind through the senses. And crucially, the senses can only detect what happens, not why. He argued that societies pass through three phases as their knowledge grows: theological (gods as causes) metaphysical (abstract concepts as causes) and finally logical (mathematics are adequate as causes). In short, scientific enquiry should stop at the mathematical analysis of data and not go beyond it to seek abstract explanations. Comte argued that science must reject abstract concepts from its method just as it had earlier rejected theological concepts. Where the enlightenment had diminished the role of religion as a source of knowledge, the Positivists now diminished the role of science. Science could give us a toolbox to predict and control nature but neither science nor anything else could tell us what reality actually is.

In spite of Hume, Comte and many other sceptics, by the later 1800's there were scientists who believed that science was nearly complete. Science had reached a very good understanding of the workings of nature. There were still a few t's to cross, i's to dot and more decimal places to reach but it was supposed that the age of great scientific discoveries was drawing to a close.

Then, into the 1900's, two major discoveries in science changed everything. One was Einstein's relativity. He started out trying to explain why light, when measured, always has the same speed even if you are moving when you measure it. Speed is distance divided by time (e.g. miles per hour). If the speed of light is always fixed, Einstein reasoned, it must be the scales of distance and time that vary. Einstein concluded that distance and time were relative, not fixed. So, things moving at or near to light's speed seem to have miles of different length from our miles and clocks that run slower than our clocks. He also suggested that mass literally distorts space and time, and found that this idea gave a much more precise account of gravity. If this all seems counter-intuitive, it gets worse: Relativity allows space and time to be distorted enough to make time travel possible. Yet we never see visitors from the future. And what if you went back in time and killed your parents? You wouldn't be born... so you wouldn't kill your parents...so you would be born.

The other great discovery was Quantum Theory, led by Danish physicist Niels Bohr. He was investigating what goes on inside atoms. Bohr found that what we thought were particles inside atoms did not move like ordinary objects. They disappeared from one place and appeared at another. It's as if we can only see a particle in a sequence of snapshots. The particle is here now and there later, but we never see it move. And in getting from here to there, a particle can take what seems like impossible routes: around corners, through solid objects, even many different ways at once. So Quantum Theory, like Relativity, raises deep paradoxes. Atoms, it would seem, are not made of ordinary material objects. Quantum Theory casts doubt on the very existence of material, at least in the naive form that we tend to think about it in everyday terms. It turns out that the universe is not like a machine made of moving parts after all. You may be tempted to doubt Quantum Theory and Relativity, yet these two theories have turned out to be science's most successful theories ever. They have both been around for more than one hundred years and have been tested by experiments probably more than any other theories. Quantum Theory and Relativity are now our best tested and most accurate theories of all time. Yet they both seem like nonsense when we relate them to our everyday experiences.

Those who thought that science had done it all must have been shocked. In just a few decades, the naive materialist view of nature was overturned. Relativity and Quantum Theory both showed that, deep down, nature is not made of ordinary material objects. Space is not an empty stage but is shaped by what goes on on-stage and whatever is on that stage, it isn't little bits of stuff whizzing around. This all sounds paradoxical in the context of our everyday experience where we think of things as static or moving material. Bohr and Einstein famously argued about the metaphysical implications of their theories but they couldn't agree. Einstein was sure that nature was made of material particles, in spite of Quantum Theory. Bohr was sure that Einstein was wrong. Yet Bohr allowed the concept of a particle to live on, even though quantum so-called particles are unlike anything that you or I would call a particle. Bohr justified this by coming up with what became known as The Copenhagen Interpretation of Quantum Theory. It presents a correspondence between the measurable properties of quantum things like electrons and classical things like bullets. But the correspondence is strained because the behaviour of an electron seems highly abstract and nothing like a bullet. Only when one takes the average behaviour of millions of electrons does the behaviour look bullet-like. So science's own interpretation has a universe of bigger things "made of" the smallest things that science calls particles yet are not actually particle-like. By the way, Einstein did not accept the Copenhagen Interpretation but Bohr won because the Interpretation still stands to this day.

Around the same time as the Copenhagen Interpretation was coming into existence, philosopher Karl Popper was looking at the scientific method from a different angle. He was seeking to understand what distinguishes science from pseudo-science. Popper noted that some non-science disciplines claimed to follow the scientific method, yet their theories seemed to be much more doubtful than the theories of physics. Two examples are Marx's sociology and Freud's psychology. So Popper set out to distinguish "good" science from bad or pseudo-science. He concluded that self-falsification is what makes science trustworthy. Popper poured cold water on the Positivists' claim that science-based knowledge is justified only if it is built bottom-up, from empirical evidence. According to Popper, the old bottom-up versus top-down arguments were irrelevant. Deduction, induction, intelligent guessing and even miraculous insights are all valid ways of doing science. But they are not valid ways to justify its correctness. Indeed there is no way to guarantee that any scientific theory is correct. But there is a way to weed out theories that are definitely incorrect. And that is to build testability into the theories themselves. Good science, said Popper, has theories that are explicitly falsifiable.

Popper found that scientific theories are alone in making precise and risky predictions. For example, they often forbid a specific occurrence so that just one case would destroy the theory. Pseudo-sciences, he found, made non-specific predictions, too vague to be falsifiable. And anyway, Popper found that pseudo-sciences were casual about failed predictions. They would just make some ad-hoc change to the theory to overcome the failure. So Popper decided to state what constitutes a good scientific theory. Where Sir Francis Bacon had defined what scientists should do, Popper defined what they should produce at the end of their efforts. He asserted that a scientific theory must be explicitly disprovable to be classed as good science. And, the theories that survive the most precise and the riskiest predictions, are thereby the best theories. The problem of induction was removed at a stroke. Theory falsification had taken over the role of justfying scientific knowledge. Hume's arguments against induction were no longer relevant. The Positivists' arguments for abandoning abstract concepts no longer applied.

Popper saw science as a sort of accelerated evolutionary process: an ongoing quest to mutate and adapt the theory-gene-pool and survival of only the fittest theories. Popper, an anti-Positivist, argued that abstract concepts are a necessary part of this process. New ideas cannot emerge unbidden from raw data and equations. They come from inventive human minds that work top-down, imagining different concepts and testing each against the data. Popper considered that Positivists were naive to think that abstract concepts could be expunged from science. There is no clear demarcation between empirical and abstract content in scientific theories. Abstractions appear throughout science because they give theories explanatory power beyond data and equations.

Later in the twentieth century, Thomas Kuhn analysed what scientists actually do. He looked behind the scenes at the scientists themselves. He found that scientists tend to have a pseudo-religious belief in existing theories. Their scepticism is alerted when data disagrees with expectations but there seems to be an assumption that while the data is good, there is no need to question the abstract concepts that qualify it. Senior scientists are, unsurprisingly, reluctant to undermine their whole life's work, which they risk doing if they give room to radically new ideas. Dissenters have more difficulty getting funding and advancing their careers. Education, not just of scientists, tends to deeply entrench current scientific views. Popularisations in books, magazines and television establish science's views almost universally. Alternative views are dismissed or made light of. But slowly and inevitably, over many decades or longer, dissent grows to a critical level. Eventually and relatively suddenly, an alternative view gains wide support. Kuhn called this a paradigm shift. It is not just one theory being replaced by a new and better theory, although this may be part of it. It is a complete revision of the scientific community's consensus view. All theories, or at least all theories within the relevant branch of science, are now seen in a new light. There is a revolution in our understanding of nature. Kuhn pointed out that paradigm shifts were changes in the mental framework within which theories are understood, and this must be a top-down, abstract world-view, the subjective consensus view of the scientific community.

Kuhn's findings showed that Postivism still lived on in science. Belief in the absolute correctness of theories, because they are built upon evidence, is a typical Positivist stance. Building ever more detail around existing theories, and shunning new abstract ideas, is typical of Positivist methods. Popper had undermined Positivism by showing that the abstract concepts within science are not a weakness so long as theories are falsifiable. But here's the problem. Abstract concepts are not likely to be falsified by unexpected data. Their falsification requires something more subtle: inconsistencies and paradoxes for example. There are numerous significant paradoxes within physics that are most apparent when one tries to reconcile classical, relativistic and quantum theories. Many decades of empirical data support these theories. It would seem that the bottom-up content of these theories has withstood the falsification test very well so far. The solution to the paradoxes must surely lie in the abstract concepts, the paradigms within which the theories are understood.

So, in the twenty first century, we find the scientific method alive and well. Science is hugely successful at discovering how nature works. Science tells you explicitly how you can prove it wrong as no other source of knowledge does. It has given us modern medicine that makes long healthy lives commonplace. It has given us modern technology that is indistinguishable from magic to most people. If science is on the wrong track, it is surely a miracle that it achieves so much. But science still retains the big picture of the universe that was passed down from classical philosophers. Scientists still speak of a universe made of material particles that somehow have strict order and laws built into their behaviour. The consensus view of science is that the universe is made of active material.

The public tend to follow science's world-view without question. It is embedded in media stories about science and astronomy and in school text books that precondition our scientists of the future with the old world-view. Scientists, when communicating with the public, reinforce the idea of material particles. In television documentaries and popular-science books, scientists describe a material world, but explain away relativity and quantum effects as "weird" behaviour of the material. While scientists don't entertain alternative top-level world-views, they simply allow the old one to continue unchallenged.

Of course, some top scientists have challenged the old world-view or at least hinted that it might be wrong. Werner Heisenberg, one of Niels Bohr's co-founders of Quantum Theory, said that atoms are not things. Lee Smolin, a current leading physicist, said that the universe is made of processes, not things. Richard Feynman said "You can't say A is made of B or vice versa. All mass is interaction". Perhaps it is unfair to imply that science ought to be seeking a new world-view. Even allowing that Popper gave science the freedom to entertain abstract ideas, science must remain rooted in data. The finest minds of the twentieth century felt compelled to explain Quantum Theory in terms of classical physics. How could they do otherwise? The whole scientific edifice at that time was the data and theories of classical physics. To reject it would be to pull the rug out from beneath their own feet. The alternative: to start with a barely understood quantum world then explain centuries of established science as some kind of illusion is simply not how science works, nor should it be. This is a task that is beyond physics and therefore lies within the realms of philosophy. So the quest for alternative answers to the question "what exists" should be, and is, undertaken by a special branch of philosophy called Ontology.

Who knows what exists?

Ontology is the study of existence. The word comes from the Greek Ontos which means 'being' or 'that which is' and logos which means 'logical discourse'. So Ontology would appear to be the place to look for the answer to "what exists?" Unfortunately, like so much of philosophy, it does not make for light reading. There is a whole genre of publications known as popular science that makes science accessible to non-experts but there is no such equivalent of popular ontology. I would not recommend looking for a book on Ontology to find an explanation of what exists. Instead, I have identified two notable attempts to question the active material world-view and offer a plausible and well-argued alternative.

Alfred North Whitehead described how reality could be a process. He famously said, almost poetically, that existence is "Not being but becoming". He proposed that events are the real fundamental elements of the universe. Events are what we experience but that's all there is. There are no objects, no material stuff. What we think of as objects are themselves made of events. This is a difficult idea to grasp but I urge you not to dismiss it too quickly. It is universally understood that events are something abstract that happens to things. The idea of an event having its own existence without it happening to something is alien to us. Whitehead showed that actually it is just a prejudice, something so deep within our psyche that we hold it as self-evident.

A more recent ontological idea than Whitehead's is called "Ontic Structural Realism" (I told you it's not easy reading!) When new scientific theories oust older ones, they often retain the mathematical structure of those old theories and merely add a more sophisticated layer of new structure. As science goes deeper, it finds ever more evidence of structure but, crucially, ever less evidence of anything material. The trend is towards a picture of nature as structured patterns. Ontic Structural Realists conclude that there are no "things" of any sort at the fundamental level of reality. Structured patterns are all that there is. It is perfectly feasible that reality is, at its most fundamental, information patterns. Material, space and time are then secondary concepts: structure in the patterns; shadows on Plato's cave wall. It is difficult to grasp ideas like this because they are so far removed from our day-to-day experience. We must keep in mind that science itself provides evidence against the concept of active material. If the universe is not made of ordinary objects, then it certainly must be made of something extraordinary that will necessarily seem strange on first encounter.

Note that ontologists don't dream up such strange ideas independently of science. They study science in great depth, especially fundamental physics and cosmology. Their ideas are constructed specifically as a way to interpret and explain the findings of science. They see their role as providing a bigger picture beyond physics. The aim is to find a world-view that makes sense of everyday experience and fundamental physics. In fact, any world-view should make sense of the whole of science and eliminate any contradictions and paradoxes. The active-material world-view does not meet this requirement. Indeed, there is no widely accepted world-view that does so at present.

Ontology interprets the theories of science and attempts to build around science, using ordinary language and simple logic, an overall picture of reality. This picture builds upon knowledge obtained from empirical and rational science. Modern philosophers are therefore strongly bound to science. They no longer deal merely in intelligent guesswork as the classical philosophers had to. In going beyond science, there is more speculation but speculation was always vital to the advancement of science. We cannot know for certain what reality is, as an absolute fact, but we can still distinguish better and worse attempts to explain it. Like a detective trying to solve a murder case, we imagine different scenarios and gradually eliminate their weaknesses until we arive at the most likely answer. Weak ontologies are ones that don't conform with known science or raise inconsistencies and paradoxes. The best ones should give a unifying picture of all of science, not just physics. Scientific investigations would eliminate weaker ones using Popper's principle: by seeking data and new experiments that would falsify them.

The quest to understand the universe has come a long way. Science does not claim to offer the view looking back in Plato's cave. Science's reputation requires that it focusses on the shadows on the cave wall because they are the only source of facts that we have. Yet, as Kuhn showed, scientists have world-views or paradigms that are not difficult to recognize. They are the classical materialist view, the relativistic view and the quantum view. Scientists step easily from one view to the other but these views are not compatible with each other. They cannot be combined without raising major paradoxes. Could there be a new science-based view from which the three existing ones can be derived while avoiding paradoxes? Such a view is certainly possible (see The Freeze-frame Universe) but may have to be so revolutionary that we just cannot believe it. Perhaps at most, science can only help us to understand what the universe is not. And all the signs are that the universe is not at all what we typically think that it is.

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