Metaphors of Cloth in Popular Physics
“Heisenberg imagined that electrons do not always exist. They only exist when someone or something watches them, or better, when they are interacting with something else” (Rovelli 17).
Theoretical physicists puzzle over having two well-established theories that are incompatible with each other: general relativity and quantum mechanics (Greene 16). Physicists looking for a new theory to unite these two subfields have a few ideas, and these new theories use systems of metaphor to elucidate the imperceptible to lay audiences (Greene 15).
Today textile metaphors often describe spacetime as something woven. In this essay, I examine the spacetime-as-textile metaphor, and its entailments, limitations, and interactions within a greater system of symbols, focusing in particular on the use of this metaphor in two popular physics books, Carlo Rovelli’s 2016 Seven Brief Lessons on Physics and Brian Greene’s chapter “Roads to Reality” in his 2004 book, The Fabric of the Cosmos. This essay touches on Rovelli's work to suggest that the spacetime-as-textile metaphor exists throughout popular physics discourse, but the primary focus of this exploration examines Greene's use of the metaphor.
Quantum Loop Gravity
Physicist Carlo Rovelli, one of the founders of loop quantum gravity theory, uses textile metaphors in his bestselling book, Seven Brief Lessons on Physics. Rovelli notes that while general relativity looks at the universe as continuous, quantum mechanics shows “leaps” between particles as they interact (40). For Rovelli, the concept of “grains of space” may be a solution to this inconsistency (43). Rovelli explains, per loop quantum gravity, that “space is not continuous, that it is not infinitely divisible but made up of grains, or ‘atoms of space’ . . . called ‘loops,’ or rings, because they are linked to one another, forming a network of relations that weaves the texture of space, like the rings of a finely woven, immense chain mail” (43). Language of “loops” and “woven chain mail” suggest the spatial interconnection of all things, but the weaving metaphor is less suitable for describing the concept of time as understood by theoretical physics (43).
Rovelli generally describes time in negatives, explaining what time is not: it does not flow; it is not absolute, but he does provide one striking image (44; 60). "For a hypothetically supersensible being, there would be no ‘flowing’ of time: the universe would be a single block of past, present, and future. But due to the limitations of our consciousness we perceive only a blurred vision of the world and live in time” (Rovelli 62). Arguing against time as “flowing,” Rovelli leaves time in the spacetime chain mail, the “grains of space” (44). Although spacetime is a single entity, the visual image of woven loops highlights the concept of space and downplays the concept of time.
Brian Greene on String Theory
Renowned physicist Brian Greene, writing about cosmology and quantum mechanics, foregrounds the spacetime-as-textile metaphor by placing it in his book title, The Fabric of the Cosmos. Greene relies heavily on textile metaphors to bring abstract concepts into view. Here I examine Greene’s introductory chapter, “Roads to Reality,” as it functions as an overture for the book and includes his own ontological and epistemological questions and interpretations, as he sees them through the lenses of myth and physics (3-22). Greene, clearly acquainted with Greek myth, opens the book with a reflection on Sisyphus and the value of life and comes back to the myth throughout the chapter as he considers how meaning, truth, reality, and knowledge interact with principles of modern physics such as relativity, probability, and the flexibility of spacetime (3). Elsewhere I explore the connections between the spacetime-as-textile metaphor and Greek myth; here I will examine Greene’s use of fabric and thread metaphors as he describes findings of modern physics.
Connecting Spacetime and Thought
Using the spacetime-as-textile metaphor in multifaceted ways, Greene writes, "we will encounter a series of developments . . . that will show how close we’ve come to wrapping our mind around the fabric of the cosmos and touching the true texture of reality” (6). Greene describes the mysterious “fabric of the cosmos” and the “true texture of reality” using an additional metaphor of “wrapping,” evoking an image of cloth and showing that Greene’s textile metaphors describe not only spacetime but also thought itself (6).
Probability, Uncertainty, and Simultaneity
Greene incorporates probability into the spacetime-as-textile metaphor, suggesting a spatialization of time, as probability typically concerns the future:
“most physicists agree that probability is deeply woven into the fabric of quantum reality . . . quantum mechanics describes a reality in which things sometimes hover in a haze of being partly one way and partly another. Things become definite only when a suitable observation forces them to relinquish quantum possibilities and settle on a specific outcome” (Greene 11).
This description quickly transitions from the spacetime-as-textile metaphor into one where “things” can “hover” until they “settle” back into the fabric (11). I imagine a thread of time, up and down, sewing, solidifying behind itself. This metaphor functions paradoxically: if the fabric of spacetime is all-encompassing, wherein the totality of matter and time exist as completely interconnected, the images of hovering and settling and depart from the fabric (partially due to the structure of English relying on prepositions to describe spatial relationships). If spacetime is a fabric, probability is not just in the fabric, probability is the fabric. And with this example language bumps up against the boundaries of concept—serving as a reminder that distinctions are not inherent to objects, but are rather constructions and projections of the way people interact with and categorize concepts (Lakoff 161).
Greene’s use of the spacetime-as-fabric metaphor to discuss both cosmology and quantum mechanics functions rhetorically to support Greene’s argument that string theory unites the two separate subfields of modern physics (11).
Threads of Thought
A similar example emerges as Greene describes the mathematically unexplainable directionality of time moving from past to future: “The question of time’s arrow provides a common thread that runs through many of the developments we’ll discuss, and it will surface repeatedly in the chapters that follow” (20). In this case, Greene’s use of a weaving metaphor, with a “common thread” that “will surface,” again refers to the fabric of the text—a thread of thought emerging as Greene weaves it into The Fabric of the Cosmos (20). By using the images of thread and fabric in multiple ways Greene connects human understanding with the universe itself.
The spacetime-as-textile metaphor is as flexible and dynamic as fabric. Because the concept of fabric depends on space outside and around the fabric, the image can immediately remind audiences of the limitations of perception. The metaphor defies the everyday reality of experience, while describing it as quotidian, comforting: cloth. By sharing the metaphor of fabric between descriptions of understanding and spacetime, Greene weaves his text and his thought and his audience’s understanding together into the concept of spacetime. The audience is not separate from the fabric of the cosmos, considering it objectively as outsiders—the audience is part of the fabric.
String Theory
The spacetime-as-textile metaphor works in conjunction with a spacetime-as-symphony metaphor as it describes superstring theory, which Greene promotes as the best unifying theory available to describe the nature of reality (18). Greene writes:
“according to superstring theory, every particle is composed of a tiny filament of energy. . . which is shaped like a little string. And just as a violin string can vibrate in different patterns, each of which produces a different musical tone, the filaments of superstring theory can also vibrate in different patterns . . . [to] produce different particle properties” (17; 18).
Examining particles and subatomic particles, physicists posit energy emerging as vibrations shaped as strings which become fabric yet make music (Greene 17-18). These two metaphors together struggle in describing time. As Rovelli genuinely asks, “What is vibrating time?” (58). Still, the polysemic relation between strings vibrating to create music which occurs invisibly in time, and strings woven to create fabric which exists visibly in space, allows for a dialectic between what the metaphor makes apparent and what it hides.
All metaphors function by highlighting certain elements and veiling others (Lakoff 163). A metaphor has a “vehicle” and a “tenor”: literary terms for what a metaphor says and what it means. “Tenor,” as a term for meaning is a homonym of another musical term. So with “string theory” we have terms of cloth and music in the polysemy of "string", just as elements of metaphors themselves use terms of cloth and music with terms like"veiling" and "tenor."
A Tapestry of Theory and Spacetime
Greene uses a tapestry metaphor to describe string theory: “Superstring theory has revealed the breadth necessary to stitch all of nature’s forces and all of matter into the same theoretical tapestry.” (18). The term “revealed” suggests its cloth-based Latin root of veiling, velum (OED). Veils cover something; yet the “fabric of the cosmos” metaphor, it seemed, was meant to describe totality, as the book's subtitle is "Space, Time, and the Texture of Reality." Greene’s statement uses metaphor to suggest that superstring theory explains the “tapestry” of spacetime, stitches the tapestry, and actually is the tapestry (18). The weaver weaves itself. This node on the symbol web of textile metaphors helps resolve the issue of conceptualizing time through fabric. The prototypical image of fabric (as Lakoff describes prototypes) resists embodying time metaphorically (Lakoff 71). But specifying that the textile is not just “fabric” but a tapestry allows for the temporal element more readily, better depicting what Rovelli calls the “single block of past, present, and future” (62). A tapestry is a fabric with a story spatialized, solidified in time: the characters’ past and future existing at once, physically close together, part of the present.
Stories as Threads
Stories-as-threads is a textile metaphor pervasive in certain discourses in Western cultures, as I have heard in common expressions such as “weaving a story,” “spinning a yarn,” and even in terms such as a “fabrication.” The connection between the concepts of stories and threads can be found in the classical Greek tradition as well, as it relates to the concepts of fate and kairos; I explore these connections here.
Crumpled Dimensions as Texture
Greene also uses the spacetime-as-textile metaphor to discuss dimensions beyond perception: “String theorists . . . have found that extra dimensions might be so tightly crumpled that they’re too small for us or any of our existing equipment to see” (19). In describing dimensions as “tightly crumpled,” Greene uses the fabric metaphor to highlight the possibility of tiny wrinkles and folds (19). The term “crumpled” suggests the consequence of forces from the outside; in physics, something moving toward its own center suggests gravity, which relies on mass (19). For the fabric of space to crumple in on its own mass while also being spread through existence suggests a complex texture, no mere linen.
Layering Perception and Reality
As Greene expands the metaphor to include textures, dimensions materialize; from here, he adds another layer of fabric (19). Greene writes: “If superstring theory is proven correct, we will be forced to accept that the reality we have known is but a delicate chiffon draped over a thick and richly textured cosmic fabric” (19). While Greene suggests there is more to reality than meets the eye, this iteration of the metaphor uses multiple fabrics of the cosmos, with separate properties: a chiffon as “the reality we have known,” veiling a deeper reality (19). Chiffon is sheer, showing lights and colors moving behind it as it obscures the “thick and richly textured cosmic fabric” (19). This instance of the fabric metaphor highlights its veiling aspect but downplays its integrative aspect.
Using a metaphor of multiple layers may undermine the meaning of the term “fabric” to describe totality, downplaying the ontological questions to emphasize the epistemological concern: that human experience cannot directly know the reality of the structure of spacetime or energy, and that the idea of “reality” itself is problematic.