Humans are curious, explanation-seeking creatures. However, all explanations are not equal. Many among us are content with mythological, religious, or otherwise simple and simplistic non-explanations of physical reality, and of how the Universe came to be. A few of us are not.
Bad and Good Explanations
A non-explanation, also called a “bad” explanation, is disconnected from what it purports to describe or decipher. Non-explanations are flexible, even fungible, and are as good—or as bad—as other, similarly situated ones. The ancient Greek mythological “explanation” of the seasons is no better than the Norse myth of why there is spring, summer, fall, and winter. Both involve gods, goddesses, and accounts based on actions and things that are divorced from the workings of nature. A myth in which a deity creates the world in ten days, and does not rest afterwards, is as “good” as the current Judeo-Christian myth.
In science, myths and hocus pocus do not make the cut. Therefore, those who search for good explanations have to work hard, and amass knowledge, because such explanations—more commonly known as “theories”—must relate to nature’s regularities and phenomena. They must also be rigid, including no arbitrary elements that can be exchanged with other, similarly haphazard features.
Scientific theories also are, in the words of physicist David Deutsch, “bold conjectures.” Knowledge is thus possible by that human quality we call “creativity.” Contrary to what empiricism proclaimed, theories are not derived from observations, while nature is not a “book,” waiting to be read. A good explanation, a theory, is a product of human creativity, sometimes springing from one mind, often from many minds over several generations.
Knowledge is required not only to explain nature, or to figure out how our bodies work and can be made to recover from sickness, but also for solving all kinds of foreseeable and unforeseeable problems. “Problems are inevitable,” Deutsch reminds us, but, with the right knowledge, they are also “soluble.” Sometimes, it is a matter of applying existing knowledge to the problem; sometimes, we must create new knowledge.
Origins: The Current Explanation
Cosmology—the study of the origin, development, and ultimate fate of the Universe—illustrates how science works. Cosmology’s Big Bang theory is an explanation of how our Universe came to be. It is an origins story, which has been modified and refined as new evidence has surfaced. It also accounts for the evolution of the Universe. The evidence in its support is overwhelming enough. Hence, it has not been superseded by a new theory. Observations and experimental data ultimately tell us how prescient, how accurate, our “bold conjectures” actually are.
In a nutshell, Big Bang cosmology proclaims that the Universe arose out of a “singularity,” a state of infinitesimal size and unfathomable potential energy, unstable enough to burst into a whole, enormous realm. Not exactly an “explosion,” the singularity expanded (“grew,” if you will) in a release of energy that yielded intense heat and electromagnetic radiation, while slowly cooling as the expansion went on.
That outburst of expansive energy produced everything in the Universe, including light and the constituents of matter—protons, neutrons, electrons, and so forth. Electrons began the dance with protons, producing the first hydrogen nuclei, while the heat and pressure of the baby universe fused many of those hydrogen nuclei into helium, a process known as Big Bang nucleosynthesis. In turn, primeval hydrogen and helium provided the raw materials for the formation of stars.
The discovery of cosmic expansion came shortly after astronomers began to realize that the Universe is much more than our galaxy, the Milky Way. More powerful telescopes, and techniques such as spectroscopy, allowed observational astronomers to, paraphrasing Marcia Bartusiak, “find the Universe.” The current estimate is that there are around 200 billion galaxies in the observable universe.
The Autonomous Reach of Explanations
The first theory of gravitation was devised by Isaac Newton, while isolated at his home in order to escape the ravages of an epidemic, the English bubonic plague of 1665-6. His theory postulates that any two massive objects exert an instantaneous attractive force on each other. Two hundred and forty years later, in 1905, Albert Einstein found that there is no such thing as instantaneous action-at-a-distance, and that the speed limit in the Universe is the speed of light. The incompatibility between Newton’s and Einstein’s notions of space and time became a problem to be solved, prompting young Einstein’s quest for a new theory of gravitation.
Cosmology as a scientific field can be traced back to 1915, with Einstein’s announcement of his finished theory of gravitation, the Theory of General Relativity. Considered one of the most beautiful theories ever devised, general relativity postulates that gravitation is the result of the warping of space and time, caused by the presence of matter and energy. Space is curved in the vicinity of massive objects like our Sun, which accounts for the orbital, curved trajectory of planets and comets in our solar system.
Moreover, time is not absolute, as a clock runs slower for someone close to a massive object, relative to the clock of an observer located farther from it. In other words, there is no such thing as a universal tick-tock. A gift that keeps on giving, general relativity has been confirmed in different physical settings, thanks to many observations and discoveries.
Since gravitation determines the motions and structures of planets, stars, solar systems, galaxies, and clusters of galaxies, a theory of gravitation is also a theory of the universe-at-large. Einstein himself, and others, worked with the solutions to the equations of general relativity, finding that they describe a dynamic universe. It would soon turn out that the Universe was expanding, meaning that space between galaxies or, more accurately, between clusters of galaxies, is increasing.
At the time, the Universe was viewed as static, so Einstein added to his equations a constant that would avoid cosmic expansion or contraction. A decade later, several observational astronomers, including Edwin Hubble, showed that galaxies are receding from each other. Einstein became convinced that he had balked at predicting the expansion of the Universe, even though his own theory pointed in that direction.
That episode shows that all good, full-fledged explanations, including of course general relativity, have a “reach,” which is independent from the desires and biases of their creators. (Bad explanations have no reach at all, which makes them useless). New theories often defy or supersede existing knowledge, pointing to new possibilities and research routes. The full reach of theories is unforeseeable, requiring to deem them as autonomous entities, not to be tampered with. Since good explanations are rigid, it is nearly impossible to tinker with them, anyway. As soon as, if ever, they do not correspond with observations and experimental results, it is time not to modify them, but to devise a new, better explanation (one with more reach than the former theory).
Newton’s theory of gravitation works in the context of physical parameters where the gravitational field is weaker than a certain threshold. Einstein’s theory works in those contexts too, but it supersedes Newton’s theory in those stronger fields in which the latter fails to deliver. To send a spaceship to the moon, Newton’s theory works fine. To predict the orbit of Mercury, to predict and explain the behavior of a binary pulsar, or the workings of a black hole, it does not. In short, Einstein’s theory has a wider reach than Newton’s.
Indeed, another reach of Einstein’s theory is the existence of black holes, stars that collapsed under their own gravity, which is so strong—the space surrounding them becomes so curved—that nothing, not even light, can escape the gravitational pull. Until 1971, black holes had not been detected, but astrophysicists in general were pretty sure that they were out there. That is another instance of theory preceding the actual observation of a phenomenon, and of telling observational scientists what to look for.
An Ethos of Criticism
Good explanations get us closer to the truth, to a thorough understanding of reality. They are created on the basis of already existent knowledge. Often, the catalyst is the emergence and identification of inconsistencies—of problems.
Knowledge is not “derived” from experience or from contemplating nature. Humans had observed nature since prehistoric times, but it was not until recently that we began to make sense of it all. Why? Because of theories, those well-crafted conjectures, always preceded by, and relying on, the accumulation of physical and mathematical knowledge. Not until the last four hundred years were the necessary cultural and social conditions for the emergence of truth-seeking sustained.
In order to allow for the continuous creation of knowledge, human societies must do away with taboos, and with the notion of authoritative knowledge—that we must uncritically yield to what certain people or institutions tell us to know or not know. More important yet, human societies must develop an ethos of criticism. Only then could humans learn to weed out bad explanations in favor of good ones, in an ongoing process that has actually made possible what we call scientific progress.
For decades now, the United States and other modern societies have been experiencing a wave of ignorance and stupidity, which has been in full display during the coronavirus crisis. The current debacle has been mainly caused, not by the virus, but by ignorance—in tandem with the destructive, narcissistic ways of regimes like those of the U.S.A.’s Trump, and Brazil’s Bolsonaro.
A global culture which overwhelmingly values realism, knowledge, truth-seeking and problem-solving should change the way we think, live, and do politics. It should also allow most humans to see through monsters like Trump, making authoritarianism unlikely. Thus, the discussion above has implications for culture and politics, as well as for how we solve problems and run organizations, institutions, and whole societies.