“Facts” and Opinion: What One “is” vs What One “does” as Seen by Modern Physical Science

Alvin M. Saperstein, Professor of Physics Emeritus, Wayne State University, Detroit Michigan

There is much ado in the current political world about facts, alternate facts, fake facts, etc.1 What is a “fact”? It is a piece of information about the world — external or internal — obtained either from trustworthy others, by direct observation and measurement, or by an explicitly rational chain of reasoning from other well established facts.2

If by observation, either by direct use of the human senses or via instrumentation, the observer must be cognizant of the possibilities and limitations of the instrument used. The process of establishing the “fact” must be open to, and agreed upon, by many other independent individuals; otherwise it is impossible to differentiate between illusion and established fact. Despite Freud3, it is very difficult for different individuals to share the essence of their respective dreams. (Actually, all meaning is communal since almost all thinking, whether awake or asleep, requires the use of words, words which are created by the community and implanted in the brain of the growing child.)

It is also vital to distinguish between a “fact” and an “opinion”4 — which also may be shared by many others. Whether or not a Picasso painting is beautiful, or a politician is a credible candidate for high office, is an opinion. Whether or not the Earth is roughly spherical or billions of years old is a well-established fact. The choice between fact and opinion cannot be left to popular vote (which may change rapidly and radically) but must rely on a well established process, usually referred to as a “science”. Whether or not a crowd watching an event is large or small is an opinion.1 How many people were in the crowd can be a fact if suitable — numerical — observations were made. Thus the use of numbers must be a key attribute of any distinction between fact and opinion. Whether Shakespeare was a great dramatist is opinion. It is possible, and many scholars have tried, to make a credible estimate — with a wide range of uncertainty — of the number of people who have read him — an estimated “fact”. When using the word correctly, there should be no need to add the qualifier “established’ to the word “fact”.

It might be useful to view facts as modern physical science sees them — specifically “quantum physics”. Traditional philosophers (and later “scientists”) have always wondered what the “world” is — material or spiritual? real external or internal to our mind? controllable or not? harmful or not? good or evil? In addition to the rather rare human curiosity — the sense of wonder as to how the world “works”, there is also a common feeling that knowledge could lead to control of our environment, private or public, possibly beneficial, e.g., a sturdy bridge could be built, dangerous illnesses may be cured, effective public policy may be created. This search for what is has led from the macro- world to the micro-world — molecules, atoms, nuclei, other, “elementary particles”5. In the 20th century, these attempts at understanding our micro-world — the foundations of our macro-world — led theoretical physicists to the creation and growth of Quantum Mechanics6 and its applicability to more and more practical aspects of the world — e.g., new structural materials, solid state electronics, molecular biology. But as the applicability of Quantum Mechanics has spread and understanding of it deepened, physicists have come to understand that they cannot understand what the micro-world is, only what it does — and the latter to an ever increasing degree. Thus the fundamental “fact” about the real physical world is what it does, not what it is.

The concept that something “is" implies permanence; it exists whether or not it is being observed. Its state of being is independent of whether there is an external world cognizant of its existence. On the contrary, what something “does” is a response to an external stimulus; an external world is required — an observer, a measurement. Prior to twentieth century physics, the two descriptors — is and does — were always assumed to go together. Something, living or otherwise, could not be seen as “doing” without existing between observations. (To the thinkers of that time, a tree falling in the forest made a sound whether or not there was a human present to hear the sound.) Since the advent of Quantum Mechanics., this is no longer the case for microscopic entities — we can no longer definitely say what something “is” between observations, only how it responds to the measurement process — what it “does”.

The progress of microphysics — from molecule to atoms to nuclei and electrons to nuclear constituents — was the assumption of smaller and smaller “particles”. All of matter, and the light with which we interacted with that matter, was shown to be made up of particles. Contrary to Aristotle, for whom the world is a continuum, with no end to its divisibility, the now known entire physical world is a collection of particles. But what is a particle? Like most words, in most languages, the world “particle” comes from ordinary, daily human experiences — in this case marbles, pebbles or grains of sand. As observed, these particles have definite shape, color, hardness, electric charge, mass, location, and motion. As we, conceptually and experimentally, went down in size to the most fundamental entities, those of which the entire rest of the physical world is constituted — the so-called “elementary particles” — we gave them a smaller set of standard characteristics - mass, electric charge (and other “coupling” strengths to other particles) and spin. Other physical characteristics of matter– shape, color, hardness, etc. — could be the manifestations of the particles acting in concert. And so, these elementary particles — of which the universe is thought to be made — were conceived to be tiny balls of definite mass, electrical charge, spin, and size — though to-date, no measurements have shown the electron to act as if it were larger than a geometric point.

The ‘is-ness” of such a ball, tiny or otherwise, is that, at any instant of time, it has a definite location and state of motion (motion is just a coordinated sequence of locations); being at rest is just a particular form of motion. Thus each such particle traverses a definite trajectory through space, having, at each instant of time, a definite position and a definite velocity. And the universe, as we came to know it, is made up of such particles, interacting with each other via various forces — gravitational, electrical, nuclear, etc. Or so we thought until the first quarter of the twentieth century.

By 1900, the electron was thought to be such a particle, uniquely associated with the atoms of matter. It could be disassociated from its atoms, and, fired from an “electron gun” in a vacuum tube and thus have its mass, spin, and electrical charge accurately measured. Using a low intensity beam, fired at a phosphorescent screen or photographic plate, a bunch of individual spots was observed — certainly characteristic of particles. As the intensity of the beam, or the observation time interval, increased, the density of spots would increase, eventually covering the entire screen or plate. Since the electron gun had a known, predetermined accelerating voltage, the electrons hitting the target had a known velocity. And so they had the expected behavior of particles — definite trajectories. Therefore, the electron is a particle, and so were all of the other atomic and sub-atomic constituents of matter. And so, by 1905, was a light beam understood as a stream of particles called “photons”.

However, experimental physics moved on. What would happen if one placed an opaque screen (a thin metal sheet) between the electron gun and the photographic or phosphorescent film and parallel to the latter? As expected, nothing would appear in the film. If a thin, rectangular slit were cut into the blocking screen, a thin line of electron dots would appear on the film, directly behind the slit — again, as expected. With increasing time or beam intensity, the density of dots would increase, eventually becoming a solid image of the slit. The image line in the film would be somewhat thicker and diffuse than the cut slit; presumably some of the electrons were hitting the edges of the slit and so were slightly deflected from their original straight line trajectories.

In the next experiment, a second slit was cut into the blocking sheet, parallel and close to the first slit. Instead of there being two line images, one behind each cut, expected as a result of there being two possible trajectories through the blocking sheet, a series of line images were observed! The brightest one appeared on the film directly behind the central obstructed region between the two cuts, a place unreachable by either of the two expected trajectories. The remaining images, evenly spaced lines, got dimmer and dimmer as they appeared further and further from the central bright image line. The observation certainly contradicted the conception of electrons as particles! The observed pattern was familiar to those familiar with the behavior of waves — water or sound — approaching a barrier with two openings in it — a wave phenomenon called “two slit interference”. Could the electron beam approaching the barrier with the two slits be a wave? But as the beam intensity was greatly diminished, it was noted that the images were built up of a number of individual spots — just as expected for particles.

But if they were particles, which of the two possible trajectories - from electron gun, through one or the other of the two slits in the barrier sheet, to the film — did they follow? If the experimenter blocked one of the slits, the observed image was identical to that previously observed in the one-slit experiment. No surprise. If both slits were kept open but an electron counter placed behind one of them and the film configured so that it only registered when the counter indicated that an electron had passed through its slit, the resultant pattern on the film was that of the single slit experiment. The electrons could pass through either slit but if you could determine which of the two they had actually passed through; the observed pattern was the single slit pattern! Thus if your observation technique is such as to determine which trajectory the electron follows, it acts like a particle; if the observation is ignorant of which trajectory is followed, the electron acts as a wave. You can no longer say what it is, only what it does in response to your observation.

Similar experiments were repeated many times with electrons and many of the other “elementary particles” (proton, neutrons, etc.) — and similar results were obtained. When only a single trajectory was possible, the “elementary particle” behaved as a particle would be expected to behave. When several paths were open to it, and the path that was chosen was unknown to the observer, it behaved as a wave would be expected to behave. The “superposition” of two or more possible particle paths led to wave like behavior. Hence we cannot know what an “elementary particle is, only what it does under specified measurement procedures. The physical “fact” is not an is but a does!

This quantum behavior of the elementary particles — universally accepted by science as the fundamental building blocks of our universe is certainly peculiar. But there have been other important examples of the transition from is to does in our human world. For example, the biological sciences know of animals, e.g., the chameleon or the octopus, of which it cannot be said that their skin color “is”, since the color or pattern varies with the conditions under which the animal is observed. The skin does change. In human psychology, it is difficult to say what a person’s mood is but relatively easy to say what the mood does under differing interactions with others. In the border area between psychology and philosophy, there is a long simmering question as to the relation between brain and mind. We know that the brain is; an anatomist can hold the complete brain in one hand; we know a great deal about its constituents, their chemistry, structure, and electrical circuitry. But the mind is only known by what it does. We do not know how it creates a poem or a theory, only that it does.

The transition from is to does does not only occur for facts; it has also occurred for commonly held opinions. For example, many groups of people, in the past and in the present, talk about, and worship, a God that is; e.g. “I, the Lord, am your God”. (Exodus 6.7). But the same God was also known via doing: “God answered him in thunder”. (Exodus 19:19). This “is” God evolved from the personification of imperfect natural objects, to beings with human-like attributes, to the singular all-knowing, all-powerful formless God of the later Hebrew Bible. But through this evolution, from Gods, to God, the deity was always conceived of as is. However, many in modern theology have abandoned this notion of the deity as a being and opted for the concept of God as the process by which persons are creative and moral, as “the spirit that promotes righteousness in the world”7, i.e., this modern deity does.

And, of course, many of us — such as some politicians — loudly proclaim what they are (a form of is) but never do (a form of does) what they say.

Whether a fact is or does — and the distinction between fact and opinion, knowledge of it is a product of a long chain of observation and rational thought. Denying a fact’s reality may lead to some short term local gains, but casts doubt on the process by which it was ascertained — rational thought and science. It is this rational process which has proven vital for the well-being and advance of the human world, as well as to the creation of devices and systems which may lead to the obliteration of that world. Just as denial of biological facts have historically led to deadly epidemics and much shortening of life, so denial of physical and social facts has led to much starvation, war and misery. It is the task of all of us, not to deny the facts but to use them for the betterment of our common world.

Footnotes

1. White House Pushes 'Alternative Facts.' — The New York Times, Jan 22, 2017
Facts VS. Alternative Facts | Time.com

2. https://en.wikipedia.org/wiki/Fact

3. https://en.wikipedia.org/wiki/Sigmund Freud

4. https://en.wikipedia.org/wiki/opinion

5. https://en.wikipedia.org/wiki/elementary particle

6. https://en.wikipedia.org/wiki/quantum mechanics

7. Mordechai M. Kaplan,” The future of the American Jew”, New York, 1949, pp.381-2.

These contributions have not been peer-refereed. They represent solely the view(s) of the author(s) and not necessarily the view of APS.