Did I leave you from my last letter with the impression that I am both master builder and in control of my emotions at all times? You may assume I am prone to exaggeration, Deuteros, not so different from the mass media you hear me lament, though my reasons are less vile. Unlike the news, I am not trying to drum up your anger so much as elicit your pity. Pity me, though, not for failing to live up to my ideals at all times, but for feeling the need to hide that I am flawed. If I should not pretend to be perfect, I would not be so ashamed to miss the mark, thus failing doubly in my thinking.
To atone for my weakness, I will revisit another branch of thinking I have discussed with you before, fundamental physics. The ancients were the masters of the human condition and we have yet to match or exceed their analyses of virtue and values, emotion and reason, motivation and action. But to modern eyes, their understanding of physics missed the mark. Or put differently, we have moved on from their thinking to develop fresh understandings of the workings of our universe.
To use my recent analogy, if the ancients found themselves building a guard’s hut by the front gate, successive generations have expanded it to a fortified watchtower, only to abandon these defensive positions altogether for a handsome, full building on the grounds of the estate. Whether today’s knowledge is but a well-appointed guest house, or we have moved into a wing of the grand house itself, we do not know. For all our progress, my dear Deuteros, I think humility is in order. Despite all that we think we’ve figured out, we cannot answer fundamental questions about this structure we inhabit. Though to be fair to Seneca, when he asked Lucilius to be the judge of disputed questions, he asked him only to
state who seems to you to say what is truest, and not who says what is absolutely true. For to do that is as far beyond our ken as truth itself.
Let’s review how we’ve come to know what we presently think is truest, though it may not be the truth yet. Just as our knowledge of the human condition has been built by accretion through the workings of generations of philosophers adding to existing corpus, so has the advancement of science proceeded. How wonderful that any can contribute! The physicist Richard Feynman described the supreme democracy of science in the first of his undergraduate lectures in physics at Caltech:
We are not concerned with where a new idea comes from – the sole test of its validity is experiment.
What fundamental rules have we learned, first from intuition and hypothesis, and subsequently proven by experiment?
One of the most interesting things we’ve learned is that we cannot know at the same time both the definite location and the definite momentum of a particle. This is called the Heisenberg uncertainty principle, and I find it fitting to start with a statement of fundamental uncertainty: an inherent property of the quantum systems that make up our reality is that not everything can be determined with precision. For certain fundamental things, we must satisfy ourselves with probabilities.
We think it quite probable the following is a fundamental law: that mass-energy is conserved, which is to say although that mass can be transformed into energy and energy into mass, the quantity of both does not change; and energy (E) and mass (m) are related to one another via the speed of light (c) as captured in the famous formula E = mc2.
Besides this mass-energy equivalence formula, Einstein also gave us special relativity (the laws of physics do not change if there is no acceleration between observers; and the speed of light is the same for all observers) and general relativity, improving upon Newton’s laws of motion themselves to describe gravity as a geometric property of space and time, the curvature of which is related to the energy and momentum of matter and radiation.
Quantum mechanics has undertaken the description of properties of nature at the atomic and subatomic scale. It is from quantum mechanics that we are forced to accept uncertainty as a definite element of nature. Objects have characteristics of both waves and particles, and can be either or both depending on when and how we observe them. From probability amplitudes, we calculate probability density functions to predict where, for example, an electron will be found in an experiment.
Quantum mechanics describes the first three of what we believe are the four fundamental forces or interactions, namely the weak nuclear, strong nuclear, electromagnetic, and gravitation. For gravitation, we still rely on Einstein’s general relativity. Physicists would dearly love to extend quantum mechanics to explain gravitation and so create a “theory of everything,” but quantum gravity has eluded our best efforts. The physicist who finds a way to not just hypothesize but actually detect the as yet hypothetical graviton particle will have performed weighty work indeed.
String theorists have proposed frameworks that are intellectually appealing because they give rise to the graviton, but they come at the cost of introducing additional dimensions to the four we currently know, for example M-theory with its eleven-dimensional model. The theories have so far yielded insights but no testable hypotheses. Can string theory be considered science at all, then, at least in the way that Feynman describes? Do we need better methods of experimentation or have we reached the limits of science to explain nature?
I recall from my earlier letter on such topics what reaction I should hear from you now: “Why are you spending your time on these questions? If they cannot be answered by today’s methods, or perhaps ever, what point is there is pondering them? Surely your hours are put to better use in taming your passions, and following the lessons that we know are valid.” If one purpose of the study of philosophy is a well-ordered mind, Deuteros, then I accept no limits on the ability of my mind to take the lessons of other disciplines. Indeed, to know that, though countless problems have been solved, countless still remain should give humankind purpose: we can make progress, we have made progress, there is progress to be made.
Did nothing exist before a random fluctuation in quantum gravity created the universe from an infinitely hot and dense Big Bang singularity (the so-called no boundary proposal), or was there some First Cause in the form of God that set everything in motion as the Stoics believed?
We think everything we can observe and test today can be explained back to the first 10-11 seconds from the creation of the universe. We speculate on what must have happened in the vanishingly small amount of time before this back to zero. Though we change our scale from the incredibly vast and long to the microscopically tiny and short, the significance of the questions increases.
Any person alive today may yield up answers to the questions that have propelled humankind’s search for meaning and for reason. Although Heisenberg tells us in some realms we must be satisfied with uncertainty, I am sure that humans will never stop searching for meaning. Is the scientific pursuit so different than our philosophical one? For centuries they were united. Even though we cannot account yet for every fraction of every second for all time, I say training yourself in fundamental rules from whatever branches of human endeavor you find them is time well spent.