The Mythos of Mathematics

‘Modern man has his ghosts and spirits too, you know.’

‘What?’

‘Oh, the laws of physics and of logic . . . the number system . . . the principle of algebraic substitution. These are ghosts. We just believe in them so thoroughly they seem real.’

Robert Pirsig, Zen and the Art of Motorcycle Maintenance

 

It is a popular position among physicists that mathematics is what ultimately lies behind the universe. When asked for an explanation for the universe, they point to numbers and equations, and furthermore claim that these numbers and equations are the ultimate reality, existing objectively outside the human mind. This view is known as mathematical Platonism, after the Greek philosopher Plato, who argued that the ultimate reality consisted of perfect forms.

The problem we run into with mathematical Platonism is that it is subject to some of the same skepticism that people have about the existence of God, or the gods. How do we know that mathematics exists objectively? We can’t sense mathematics directly; we only know that it is a useful tool for dealing with reality. The fact that math is useful does not prove that it exists independently of human minds. (For an example of this skepticism, see this short video).

Scholars George Lakoff and Rafael Nunez, in their book Where Mathematics Comes From: How the Embodied Mind Brings Mathematics into Being, offer the provocative and fascinating thesis that mathematics consists of metaphors. That is, the abstractions of mathematics are ultimately grounded in conceptual comparisons to concrete human experiences. In the view of Lakoff and Nunez, all human ideas are shaped by our bodily experiences, our senses, and how these senses react to our environment. We try to make sense of events and things by comparing them to our concrete experiences. For example, we conceptualize time as a limited resource (“time is money”); we conceptualize status or mood in terms of space (happy is “up,” while sad is “down”); we personify events and things (“inflation is eating up profits,” “we must declare war on poverty”). Metaphors are so prevalent and taken for granted, that most of the time we don’t even notice them.

Mathematical systems, according to Lakoff and Nunez, are also metaphorical creations of the human mind. Since human beings have common experiences with space, time, and quantities, our mathematical systems are similar. But we do have a choice in the metaphors we use, and that is where the creative aspect of mathematics comes in. In other words, mathematics is grounded in common experiences, but mathematical conceptual systems are creations of the imagination. According to Lakoff and Nunez, confusion and paradoxes arise when we take mathematics literally and don’t recognize the metaphors behind mathematics.

Lakoff and Nunez point to a number of common human activities that subsequently led to the creation of mathematical abstractions. The collection of objects led to the creation of the “counting numbers,” otherwise known as “natural numbers.” The use of containers led to the notion of sets and set theory. The use of measuring tools (such as the ruler or yard stick) led to the creation of the “number line.” The number line in turn was extended to a plane with x and y coordinates (the “Cartesian plane“). Finally, in order to understand motion, mathematicians conceptualized time as space, plotting points in time as if they were points in space — time is not literally the same as space, but it is easier for human beings to measure time if it is plotted on a spatial graph.

Throughout history, while the counting numbers have been widely accepted, there have been controversies over the creation of other types of numbers. One of the reasons for these controversies is the mistaken belief that numbers must be objectively real rather than metaphorical. So the number zero was initially controversial because it made no sense to speak literally of having a collection of zero objects. Negative numbers were even more controversial because it’s impossible to literally have a negative number of objects. But as the usefulness of zero and negative numbers as metaphorical expressions and in performing calculations became clear, these numbers became accepted as “real” numbers.

The metaphor of the measuring stick/number line, according to Lakoff and Nunez, has been responsible for even more controversy and confusion. The basic problem is that a line is a continuous object, not a collection of objects. If one makes an imaginative metaphorical leap and envisions the line as a collection of objects known as segments or points, that is very useful for measuring the line, but a line is not literally a collection of segments or points that correspond to objectively existing numbers.

If you draw three points on a piece of paper, the sum of the collection of points clearly corresponds to the number three, and only the number three. But if you draw a line on a piece of paper, how many numbers does it have? Where do those numbers go? The answer is up to you, depending on what you hope to measure and how much precision you want. The only requirement is that the numbers are in order and the length of the segments is consistently defined. You can put zero on the left side of the line, the right side of the line, or in the middle. You can use negative numbers or not use negative numbers. The length of the segments can be whatever you want, as long as the definitions of segment length are consistent.

The number line is a great mental tool, but it does not objectively exist, outside of the human mind. Neglecting this fact has led to paradoxes that confounded the ancient Greeks and continue to mystify human beings to this day. The first major problem arose when the Greeks attempted to determine the ratio of the sides of a particular polygon and discovered that the ratio could not be expressed as a ratio of whole numbers, but rather as an infinite, nonrepeating decimal. For example, a right triangle with two shorter sides of length 1 would, according to the Pythagorean theorem, have a hypotenuse length equivalent to the square root of 2, which is an infinite decimal: 1.41421356. . .  This scandalized the ancient Greeks at first, because many of them had a religious devotion to the idea that whole numbers existed objectively and were the ultimate basis of reality. Nevertheless, over time the Greeks eventually accepted the so-called “irrational numbers.”

Perhaps the most famous irrational number is pi, the measure of the ratio between the circumference of a circle and its diameter: 3.14159265. . . The fact that pi is an infinite decimal fascinates people to no end, and scientists have calculated the value of pi to over 13 trillion digits. But the digital representation of pi has no objective existence — it is simply a creation of the human imagination based on the metaphor of the measuring stick / number line. There’s no reason to be surprised or amazed that the ratio of the circumference of a circle to its diameter is an infinite decimal; lines are continuous objects, and expressing lines as being composed of discrete objects known as segments is bound to lead to difficulties eventually. Moreover, pi is not necessary for the existence of circles. Even children are perfectly capable of drawing circles without knowing the value of pi. If children can draw circles without knowing the value of pi, why should the universe need to know the value of pi? Pi is simply a mental tool that human beings created to understand the ratio of certain line lengths by imposing a conceptual framework of discrete segments on a continuous quantity. Benjamin Lee Buckley, in his book The Continuity Debate, underscores this point, noting that one can use discrete tools for measuring continuity, but that truly continuous quantities are not really composed of discrete objects.

It is true that mathematicians have designated pi and other irrational numbers as “real” numbers, but the reality of the existence of pi outside the human mind is doubtful. An infinitely precise pi implies infinitely precise measurement, but there are limits to how precise one can be in reality, even assuming absolutely perfect measuring instruments. Although pi has been calculated to over 13 trillion digits, it is estimated that only 39 digits are needed to calculate the volume of the known universe to the precision of one atom! Furthermore, the Planck length is the smallest measurable length in the universe. Although quite small, the Planck length sets a definite limit on how precise pi can be in reality. At some point, depending on the size of the circle one creates, the extra digits in pi are simply meaningless.

Undoubtedly, the number line is an excellent mental tool. If we had perfect vision, perfect memory, and perfect eye-hand coordination, we wouldn’t need to divide lines into segments and count how many segments there are. But our vision is imperfect, our memories fallible, and our eye-hand coordination is imperfect. That is why we need to use versions of the number line to measure things. But we need to recognize that we are creating and imposing a conceptual tool on reality. This tool is metaphorical and, while originating in human experience, it is not reality itself.

Lakoff and Nunez point to other examples of metaphorical expressions in mathematics, such as the concept of infinity. Mathematicians discuss the infinitely large, the infinitely small, and functions in calculus that come infinitely close to some designated limit. But Lakoff and Nunez point out that the notion of actual (literal) infinity, as opposed to potential infinity, has been extremely problematic, because calculating or counting infinity is inherently an endless process. Lakoff and Nunez argue that envisioning infinity as a thing, or the result of a completed process, is inherently metaphorical, not literal. If you’ve ever heard children use the phrase “infinity plus one!” in their taunts, you can see some of the difficulties with envisioning infinity as a thing, because one can simply take the allegedly completed process and start it again. Oddly, even professional mathematicians don’t agree on the question of whether “infinity plus one” is a meaningful statement. Traditional mathematics says that infinity plus one is still infinity, but there are more recent number systems in which infinity plus one is meaningful. (For a discussion of how different systems of mathematics arrive at different answers to the same question, see this post.)

Nevertheless, many mathematicians and physicists fervently reject the idea that mathematics comes from the human mind. If mathematics is useful for explaining and predicting real world events, they argue, then mathematics must exist in objective reality, independent of human minds. But why is it important for mathematics to exist objectively? Isn’t it enough that mathematics is a useful mental tool for describing reality? Besides, if all the mathematicians in the world stopped all their current work and devoted themselves entirely to proving the objective existence of mathematical objects, I doubt that they would succeed, and mathematical knowledge would simply stop progressing.

What is “Mythos” and “Logos”?

The terms “mythos” and “logos” are used to describe the transition in ancient Greek thought from the stories of gods, goddesses, and heroes (mythos) to the gradual development of rational philosophy and logic (logos). The former is represented by the earliest Greek thinkers, such as Hesiod and Homer; the latter is represented by later thinkers called the “pre-Socratic philosophers” and then Socrates, Plato, and Aristotle. (See the book: From Myth to Reason? Studies in the Development of Greek Thought).

In the earliest, “mythos” stage of development, the Greeks saw events of the world as being caused by a multitude of clashing personalities — the “gods.” There were gods for natural phenomena such as the sun, the sea, thunder and lightening, and gods for human activities such as winemaking, war, and love. The primary mode of explanation of reality consisted of highly imaginative stories about these personalities. However, as time went on, Greek thinkers became critical of the old myths and proposed alternative explanations of natural phenomena based on observation and logical deduction. Under “logos,” the highly personalized worldview of the Greeks became transformed into one in which natural phenomena were explained not by invisible superhuman persons, but by impersonal natural causes.

However, many scholars argue that there was not such a sharp distinction between mythos and logos historically, that logos grew out of mythos, and elements of mythos remain with us today.

For example, ancient myths provided the first basic concepts used subsequently to develop theories of the origins of the universe. We take for granted the words that we use every day, but the vast majority of human beings never invent a single word or original concept in their lives — they learn these things from their culture, which is the end-product of thousands of years of speaking and writing by millions of people long-dead. The very first concepts of “cosmos,” “beginning,” nothingness,” and differentiation from a single substance — these were not present in human culture for all time, but originated in ancient myths. Subsequent philosophers borrowed these concepts from the myths, while discarding the overly-personalistic interpretations of the origins of the universe. In that sense, mythos provided the scaffolding for the growth of philosophy and modern science. (See Walter Burkert, “The Logic of Cosmogony” in From Myth to Reason: Studies in the Development of Greek Thought.)

An additional issue is the fact that not all myths are wholly false. Many myths are stories that communicate truths even if the characters and events in the story are fictional. Socrates and Plato denounced many of the early myths of the Greeks, but they also illustrated philosophical points with stories that were meant to serve as analogies or metaphors. Plato’s allegory of the cave, for example, is meant to illustrate the ability of the educated human to perceive the true reality behind surface impressions. Could Plato have made the same philosophical point in a literal language, without using any stories or analogies? Possibly, but the impact would be less, and it is possible that the point would not be effectively communicated at all.

Some of the truths that myths communicate are about human values, and these values can be true even if the stories in which the values are embedded are false. Ancient Greek religion contained many preposterous stories, and the notion of personal divine beings directing natural phenomena and intervening in human affairs was false. But when the Greeks built temples and offered sacrifices, they were not just worshiping personalities — they were worshiping the values that the gods represented. Apollo was the god of light, knowledge, and healing; Hera was the goddess of marriage and family; Aphrodite was the goddess of love; Athena was the goddess of wisdom; and Zeus, the king of the gods, upheld order and justice. There’s no evidence at all that these personalities existed or that sacrifices to these personalities would advance the values they represented. But a basic respect for and worshipful disposition toward the values the gods represented was part of the foundation of ancient Greek civilization. I don’t think it was a coincidence that the city of Athens, whose patron goddess was Athena, went on to produce some of the greatest philosophers the world has seen — love of wisdom is the prerequisite for knowledge, and that love of wisdom grew out of the culture of Athens. (The ancient Greek word philosophia literally means “love of wisdom.”)

It is also worth pointing out that worship of the gods, for all of its superstitious aspects, was not incompatible with even the growth of scientific knowledge. Modern western medicine originated in the healing temples devoted to the god Asclepius, the son of Apollo, and the god of medicine. Both of the great ancient physicians Hippocrates and Galen are reported to have begun their careers as physicians in the temples of Asclepius, the first hospitals. Hippocrates is widely regarded as the father of western medicine and Galen is considered the most accomplished medical researcher of the ancient world. As love of wisdom was the prerequisite for philosophy, reverence for healing was the prerequisite for the development of medicine.

Karen Armstrong has written that ancient myths were never meant to be taken literally, but were “metaphorical attempts to describe a reality that was too complex and elusive to express in any other way.” (A History of God) I am not sure that’s completely accurate. I think it most likely that the mass of humanity believed in the literal truth of the myths, while educated human beings understood the gods to be metaphorical representations of the good that existed in nature and humanity. Some would argue that this use of metaphors to describe reality is deceptive and unnecessary. But a literal understanding of reality is not always possible, and metaphors are widely used even by scientists.

Theodore L. Brown, a professor emeritus of chemistry at the University of Illinois at Urbana-Champaign, has provided numerous examples of scientific metaphors in his book, Making Truth: Metaphor in Science. According to Brown, the history of the human understanding of the atom, which cannot be directly seen, began with a simple metaphor of atoms as billiard balls; later, scientists compared atoms to plum pudding; then they compared the atom to our solar system, with electrons “orbiting” around a nucleus. There has been a gradual improvement in our models of the atom over time, but ultimately, there is no single, correct literal representation of the atom. Each model illustrates an aspect or aspects of atomic behavior — no one model can capture all aspects accurately. Even the notion of atoms as particles is not fully accurate, because atoms can behave like waves, without a precise position in space as we normally think of particles as having. The same principle applies to models of the molecule as well. (Brown, chapters, 4-6)  A number of scientists have compared the imaginative construction of scientific models to map-making — there is no single, fully accurate way to map the earth (using a flat surface to depict a sphere), so we are forced to use a variety of maps at different scales and projections, depending on our needs.

Sometimes the visual models that scientists create are quite unrealistic. The model of the “energy landscape” was created by biologists in order to understand the process of protein folding — the basic idea was to imagine a ball rolling on a surface pitted with holes and valleys of varying depth. As the ball would tend to seek out the low points on the landscape (due to gravity), proteins would tend to seek the lowest possible free energy state. All biologists know the energy landscape model is a metaphor — in reality, proteins don’t actually go rolling down hills! But the model is useful for understanding a process that is highly complex and cannot be directly seen.

What is particularly interesting is that some of the metaphorical models of science are frankly anthropomorphic — they are based on qualities or phenomena found in persons or personal institutions. Scientists envision cells as “factories” that accept inputs and produce goods. The genetic structure of DNA is described as having a “code” or “language.” The term “chaperone proteins” was invented to describe proteins that have the job of assisting other proteins to fold correctly; proteins that don’t fold correctly are either treated or dismantled so that they do not cause damage to the larger organism — a process that has been given a medical metaphor: “protein triage.” (Brown, chapters 7-8) Even referring to the “laws of physics” is to use a metaphorical comparison to human law. So even as logos has triumphed over the mythos conception that divine personalities rule natural phenomena, qualities associated with personal beings have continued to sneak into modern scientific models.

The transition of a mythos-dominated worldview to a logos-dominated worldview was a stupendous achievement of the ancient Greeks, and modern philosophy, science, and civilization would not be possible without it. But the transition did not involve a complete replacement of one worldview with another, but rather the building of additional useful structures on top of a simple foundation. Logos grew out of its origins in mythos, and retains elements of mythos to this day. The compatibilities and conflicts between these two modes of thought are the thematic basis of this website.

Related: A Defense of the Ancient Greek Pagan Religion