Reality is that which, when you stop believing in it, doesn’t go away.
Philip K. Dick
Dick was an American science fiction writer whose novels and short stories often depict the psychological struggles of characters in surrealistic situations. He is perhaps best known popularly for his 1964 novel Do Androids Dream of Electric Sheep?, which was adapted for the silver screen in 1982 as the iconic Blade Runner, starring Harrison Ford.
In colloquial discourse, the word “real” comes up in a wide variety of phrases, e.g.,
· Let’s get real
· Let’s keep it real
· Real estate
· In real time
· The real deal
· It’s the real thing
· Real soon now
· Real numbers
· The real McCoy
· In real life
· For real
· It’s been real
· Real men (insert your favorite predicate)
· Make a real difference
· A real doozy
A similar list could be constructed for “reality”. In most of these, the connotation is “actual”, “genuine”, “authentic”, “honest”, or the like. But in this discussion, we need a more rigorous definition of our subject matter. In what follows, I have used a broad range of sources. One of the most useful has been the Stanford Encyclopedia of Philosophy, from which I frequently excerpt below.
How Do We Get Real?
In the philosophy of metaphysics, there is a vast landscape of dialogue on reality and realism, hotly contested for at least three thousand years, and unresolved to this day.
Metaphysics is the study of the fundamental nature of reality. It derives from two Greek words: μετα (meta, beyond) and φυσικός (physikos, natural or physical). Metaphysics attempts to describe the reality of the world — whatever that “really” means — and is concerned with things that exist apart from what is immediately apparent in the physical world around us. We adopt the following definition of realism, in broad agreement with many sources:
In philosophy, the viewpoint which accords to things which are known or perceived, an existence or nature which is independent of whether anyone is thinking about or perceiving them.
Of course, the problem with all definitions is that they use terms which themselves require definition, in this case, “existence”. One description is posed in terms of “properties”, things that can be attributed to objects, the ways that they “are”. The technical term for this attribution is instantiation, the concrete realization of a property in an object.
If I say that “roses are red, violets are blue”, this is to say that the property of redness is instantiated in roses (well, in the red ones LOL), and that of blueness in violets. This begs the question of what we mean by “red” and “blue”. Although I am unable — no one is — of describing how red feels when I see something red, I assume that you feel the same thing, or we would not be able to agree that “A rose is a rose is a rose is a rose.” (Gertrude Stein, in Sacred Emily). We say that something exists if there is a property which is instantiated in some corresponding object.
The Reality of Mathematics and Physics
Are mathematical relationships, and by extension physical ones, real? Ask those who labor in this field (joyously, by the way), and many will answer that mathematics exists independently of any of its connections to objects in the physical world and which we commonly think of as real. To me, the integers (1, 2, 3, …) exist because there are objects, the entities just enumerated, that express the desired properties but are neither material nor mental.
If the integer 17 is only a mental object, is it unique in its existence?
Whose mind contains the number 17? Is there one 17 in your mind and another in mine? In that case, the appearance of a common mathematical subject matter would be an illusion.
Eugene Wigner (1902–1995) was one of the preeminent theoretical physicists of the 20th century. He was a consummate mathematician (this literally goes without saying, can’t have the one without the other), and one of his most famous essays is The Unreasonable Effectiveness of Mathematics in the Natural Sciences.
The miracle of the appropriateness of the language of mathematics for the formulation of the laws of physics is a wonderful gift which we neither understand nor deserve.
In a review of this essay, the science historian José Ferreirós wrote,
The enormous usefulness of mathematics in the natural sciences is something bordering on the mysterious and there is no rational explanation for it. Ingenuity, inventiveness, the skill of the virtuoso to develop interesting connections, guided by a sense of formal beauty and a basic concern for logical coherence, are what drive pure mathematics.
In a recent interview with the contemporary quantum field theorist S. James (Jim) Gates, Jr., this exchange occurred:
Q: “If we come into contact with extraterrestrial intelligent life, will we find that they have discovered (or unveiled) the same mathematics that we understand?
A: “They will know about π.”
This seems reasonable: The geometric nature of a circle is encapsulated in two statements. 1) A circle is the set of all points a specific distance r (the radius) from an arbitrary point in the two–dimensional plane, and 2) The ratio of the circumference of a circle to its radius is a constant, the transcendental number π (3.1415926…, ad infinitum), whose digits neither terminate nor repeat. It crops up over and over again in all branches of mathematics, many of which have nothing to do with circles at all.
It seems to me that this cannot depend on whether we are or are not thinking about π itself, or more broadly, about any of the concepts and relationships of mathematics, and therefore that not only does π exist, so must the whole of mathematics, hence they must both be real.
What about physical laws and relationships? We need not restrict the discussion to human perception or learning. Dogs have an intimate practical knowledge of the kinematics of two–dimensional motion. How do we know this? Because when we throw a ball into the air, they can catch it. They could not do this without being able to predict where the ball is going to be based on where it is now, and how to position themselves so that their mouth and the ball coincide at some particular point of space and time (a “simultaneous event” in the language of special relativity). It does not matter whether they are able to solve Newton’s Laws of Motion, or if they have a neurophysical algorithm to solve the differential equation known as the Pursuit Curve. So, do dogs “know” this elementary branch of mathematical physics, or do they merely instantiate it? Either way, it is real according to our criteria.
Am I Real?
To address this ultimate existential enigma, I must first ask what I am. Is an immaterial pattern, one not embodied in some way, like a dress pattern or a construction blueprint, real? What about one realized in an object? Essentially, I am an embodied pattern, completely determined as I exist now by the current state of my genome and phenome. The genome is the set of all biological information specified by my DNA. The human genome comprises about 3 billion base pairs distributed among 23 chromosomes, the point being that the genome is finite. The phenome is the set of all possible phenotypes expressed in living tissue. Examples of phenotypes are skin, hair, and eye color; height and weight; or any other physical attribute. These in turn are only a very small subset of the observable structure, function, or behavior of a living organism. In principle this can vastly outnumber the collection of base pairs, so that the phenotype is essentially unbounded.
Due to cellular death (apoptosis), the body must through cell division replace the lost tissue using fresh material from food, water, and air ingested and metabolized by the organism. About 75% of all the atoms in our bodies are replaced every two weeks. As much as 98% of an organism is replaced in one year, and every atom in it once every five years. We continually take up life’s building blocks from our environment and return them to the environment after we are done with them. After death, all our materials are recycled, not back into ourselves but into other terrestrial life.
The ship of Theseus, also known as Theseus’ paradox, is a thought experiment that raises the question of whether an object that has had all of its components replaced remains fundamentally the same object. It was first introduced in Greek legend as reported by the historian, biographer, and essayist Plutarch:
The ship wherein Theseus and the youth of Athens returned from Crete had thirty oars, and was preserved by the Athenians down even to the time of Demetrius Phalereus, for they took away the old planks as they decayed, putting in new and stronger timber in their places, in so much that this ship became a standing example among the philosophers, for the logical question of things that grow; one side holding that the ship remained the same, and the other contending that it was not the same.
The paradox involves what we mean by “same”. If the same materials, then no. If the same functions, then yes. However, the Ship of Theseus is a fictional construct, an idea, while I am not. Are ideas real? I have an idea that even if they are not, I am.
The Reality of Music
Music is a wonderful metaphysical counterpart of mathematics, perhaps the quintessential one. In both disciplines, there exists a symbolic language to describe the definition and development of concepts, and some of us have learned to read and write in both languages. But most of us appreciate music from an intensely emotional and aesthetic perspective when we hear it, and many can sing or play an instrument without being able to read a musical score. Similarly, theoretical mathematicians can “hear” the beauty of their concepts in their “mind’s ear”, as it were — there is no corresponding physical sense that carries over in the analogy. The same can be said for any other form of art.
I Can’t Get Out of My Head
We are inescapably trapped within our own minds — our perceptions of the external world (assuming such a thing actually exists, haha) are entirely subjective and highly unreliable. This lack of fidelity extends beyond the domain of our biological senses and applies to any information we obtain using technological means. We all at one time or another have experienced a false reading from some instrument — in fact, I get this feeling every time I step on my bathroom scale.
The primary task of a scientist or psychiatrist is to persuade people to be skeptical about their own beliefs, to critically examine the evidence for their assumptions and to not automatically believe their own thoughts and perceptions. Still, subjective perception is the primary tool we use to obtain the data by which we judge the world and its reality.
Our understanding of what is objectively real depends on the assumption that what we perceive is an approximately faithful representation of what actually is. This seems reasonable on the basis that we are currently having those perceptions. Presumably, evolution has made us this way in order that we may survive. If I mistake a mastodon — which I hope to be able to bring down and slice into steaks to throw on the barbie — for a saber–toothed tiger, I’m certain to run the other way and get no meal at all. If my mistake is realized in the other direction, I’m likely to end up as the meal instead.
On this view, material objects in our environment, and the changes they exhibit with the passage of time, are real if they can be sensed or detected, and if it is possible to make quantitative, repeatable measurements of their properties that enable us to make well–judged decisions about what to do in the immediate future based on our understanding of the here and now.
Is It This, or That, or Even Both?
Recently, I was telling a friend that I had just started writing an essay on the nature of objective reality, indeed, this very essay. I knocked on the table in front of us and asked him if he thought the table was real. In many of the senses I have described above, we both would agree that it is. But then I asked him to consider the microscopic properties of the table, down to the level of individual atoms and the protons, neutrons, and electrons from which they are assembled. While he is a trained engineer, and this is no criticism at all, he is only vaguely acquainted with the basics of quantum mechanics, which describes properties of the fundamental particles of nature — their masses, electrical charges, positions, and velocities — in terms of a mathematical expression called a wavefunction.
Quantum mechanics is without question the most successful physical theory ever invented (or perhaps, discovered) by the human intellect. In every experiment that has been devised to test the theory, the outcomes are always exactly that predicted by the theory, to an astonishing level of precision, as much as 14 digits (significant figures) after the decimal point. Only one other example comes anywhere close, Einstein’s great theories of special and general relativity. Now the question arises, since the wave function is so successful at predicting the outcome of experiment, is it real? In other words, is a proton in an atomic nucleus an actual physical object, or is it purely a mathematical entity? Or, perhaps, is it both? Can the sub–atomic constituents of atoms, even atoms and molecules themselves, simultaneously be particles and waves?
Sophisticated experiments show unequivocally that both light and matter exhibit this so–called wave–particle duality. In a famous experiment called the photoelectric effect, the observed outcome can only be predicted successfully, be real if you like, if the radiation striking the apparatus is a stream of photons, individual particles of light. Conversely, in the equally famous two–slit experiment, the outcome can only be understood if the radiation is a continuous wave. It seems that if you look for a particle, you find a particle. If you look for a wave, you find a wave. Dichotomies like this are quite common in the world of quantum physics. Richard Feynman, one of the most brilliant and influential physicists of the 20th century, remarked that, “No one understands quantum mechanics.” This is still true today, more than 120 years after its discovery and 30 years after Feynman’s death.
I Really Don’t Care
I’m just kidding! I really do care, though some or even many will not. But this ancient, controversial discussion remains unresolved and may stay that way. I often repeat myself, so why not here? This post examines the metaphysical universe. In my previous post, Starry, Starry Night, I reflected on the wonders of the physical universe. There, I quoted Shakespeare’s take on the nature of mystery, and it seems no less apt here:
O day and night, but this is wondrous strange.
And therefore as a stranger give it welcome.
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
All the best,
From Broomall, PA on Tuesday, July 5 at 9:30 AM,