Among these terrestrial anomalies is the sheer smallness of Earth’s surface. Our planet is so remarkably compact that a beam of light can travel around its entire circumference in a mere tenth of a second—a scale far smaller than human senses are capable of perceiving organically. This terrestrial compactness shapes how we communicate, making global interactions feel instantaneous. People can converse seamlessly via telephone between Paris and Shanghai, experiencing the connection as though standing right next to each other. Yet, such effortless communication would be impossible with a companion residing in a different solar system, where years must pass just for a signal to return from even the nearest neighboring stars.
This localized smallness instills in us the comforting illusion of a shared, common time. It makes intuitive sense to ask what might be happening somewhere else in the world "right now," under the assumption that a simple phone call could immediately provide the answer. But this assumption breaks down entirely when applied to the vast expanse of the cosmos. While the concept of a shared time functions reliably enough among neighbors on the same planet, it completely fails to describe reality across the rest of the universe. Much like a child born in a secluded village who naturally assumes the entire world mirrors that village, humans routinely project local conditions onto the cosmos at large.
Our terrestrial environment also shapes our fundamental understanding of matter. On Earth, we are surrounded by discrete objects—solid entities like stones, pens, and houses that are well-defined and stable over time. This daily familiarity conditions us to believe that nature itself is inherently constructed of such rigid "things." Yet, simply considering massive gas giants like Jupiter and Saturn, or our own Sun, reveals that solidity is far from universal. Jupiter and Saturn are worlds vastly larger than Earth where countless complex phenomena unfold, yet those phenomena are entirely fluid. On Saturn, there are no solid, well-defined objects; phenomena there cannot be understood in terms of static "things."
Furthermore, Earth’s surface is enveloped by an atmosphere of air, a substance so evanescent that humans frequently treat it as if it were entirely absent. When we call a glass "empty," we ignore the reality that it is actually full of air. This perceived emptiness leads us to imagine the existence of absolute empty space, even though the wider universe contains no regions that are truly, completely empty.
Compounding these perceptions is the rigidity of Earth’s continents. Roughly one-quarter of the planet’s surface is remarkably stable, with earthquakes and geological shifts occurring slowly enough to offer a rare navigational advantage. This relative permanence allows humanity to assign static names to specific geographic regions and use them as fixed anchors—such as declaring "I am in Princeton" or "I am on Ponte Pietra in Verona." If Earth were entirely covered by restless, shifting oceans, locating positions would be infinitely more complex, as experienced mariners have always known. The existence of locations fixed relative to one another through continental rigidity encourages a static view of space that simply does not hold true elsewhere in the universe. It allows us to comfortably claim we are "staying in the same place," when what we actually mean is that we are not moving relative to Earth’s solid crust. On Jupiter, by contrast, the very meaning of staying in the same place dissolves into ambiguity.
Gravity, too, behaves with uniform reliability across the Earth’s surface, ensuring that the duration between separating from someone and reuniting remains roughly consistent for everyone. In the wider universe, however, time passes at different rates for different travelers, meaning that upon reunion, they will generally have aged by differing numbers of years. The localized consistency of terrestrial time imbues humanity with a peculiar intuition regarding temporality—one that fails outside our planetary neighborhood.
This tendency to mistake local peculiarities for universal truths underpins the entire challenge of scientific discovery. As Rovelli notes, it is not always easy to free ourselves from the outlook of our native village. Even learning that felines are called gatti in Rome and billee in New Delhi does not stop humans from clinging to the instinctive belief that "cat" is somehow the proper, true name of the animal. Reality is fundamentally more complex and varied than our immediate experiences suggest.
This cognitive limitation becomes strikingly evident when examining the concept of motion. Consider an everyday object nearby, such as the chair or sofa currently supporting you. Ask yourself whether it is stationary or in motion, and if moving, at what speed.
The immediate, intuitive response is that the chair is completely still, provided you are not reading these words aboard a moving train or airplane. Yet, even if you are sitting quietly in a room, the Earth itself is constantly rotating on its axis and orbiting the Sun, carrying everything on its surface along at a considerable velocity. Zoom out further, and our entire solar system is rotating alongside our galaxy at tremendous speed. When pushed to identify an ultimate reference point—a truly still, objective anchor against which the chair’s absolute speed can be measured—physics delivers a definitive negative answer.
There is no ultimate reference point, nothing truly stationary, and no intrinsic meaning to an objective, non-relative notion of velocity. This fundamental aspect of nature was first intuited by Galileo some four centuries ago and subsequently refined through the development of classical mechanics. Motion only holds meaning relative to something else; questioning whether an object is moving or stationary in and of itself is entirely meaningless. Humans routinely employ implicit reference points for convenience—defining "stillness" relative to the Earth’s surface, a moving train’s interior, or the Sun when mapping planetary orbits. Yet, in our current scientific understanding of the cosmos, an absolute reference point simply does not exist.
Despite this well-established physical reality, Rovelli points out that humanity has barely begun to grapple with just how radical the concept of relative speed truly is. During a lecture tour, the physicist befriended a brilliant young philosopher at Princeton University’s esteemed philosophy department. While the philosopher fully understood the equations and mechanics of physics, he ultimately confessed that he did not actually believe them. Accepting that absolute motion could not be measured, the philosopher nonetheless insisted that whether an object was moving or stationary must remain an objective, real fact independent of measurement.
When pressed on why he held this conviction despite centuries of contrary scientific evidence, the philosopher explained that it is simply the inherent nature of the concept of motion that a thing must be either moving or still. His worldview demanded that reality conform to human concepts.
The error, Rovelli argues, lies not in the philosopher’s precise conceptual analysis of movement, but in the failure to recognize that this specific mental concept is entirely inadequate for describing the actual physical world. The philosopher mistook his own intuition—forged through limited, everyday experience as a slow-moving organism on the solid surface of a small planet—for a universal truth more reliable than centuries of accumulated human knowledge.
Concepts are the inevitable products of experience. When that experience is inherently limited, those concepts can easily prove inadequate for accurately accounting for the wider real world. To better understand the universe, humanity must allow its conceptual frameworks to evolve, even when those evolving truths initially feel deeply counterintuitive. A major pitfall in contemporary philosophy and human thought alike is the persistent trap of believing that familiar concepts are inherently adequate for understanding reality far beyond the specific contexts in which those concepts were originally shaped. Without consciously breaking free from these deeply ingrained mental frameworks, humanity risks remaining forever like the child who mistakes a single village for the entire universe.
