Time is a concept so familiar and fundamental that many people never question whether it exists naturally or if it is merely a “product” of human invention.
For anyone anxiously watching the clock while trying to finish a test or rushing to catch a flight at the airport, the question: does time really exist? may seem like a joke. However, the truth is that humanity has pondered this question for at least 2,500 years, and to this day, no one has provided a fully satisfactory answer.
If time is not a fundamental component of the universe, could it simply be something humans invented to explain what we do not understand?
Contrasting Views on the Existence of Time
Around 500 BC, Heraclitus of Ephesus observed that if we bathe twice in the same river, both we and the river are never the same as before. This concept inspired Plato, who called it panta rei, meaning “everything flows.” Heraclitus’s philosophy is based on the passage of time.
At the same time, the philosopher from Elea held an opposing view: nothing changes; everything remains in its place. Both doctrines inspired differing perspectives on time for centuries to come.
The truth is that humanity has pondered the question of whether time exists for at least 2,500 years. (Illustrative image)
However, in the 19th century, physicist Ludwig Boltzmann wrote: “For the universe, the two directions of time are indistinguishable, just as there is no up or down in space.” Boltzmann’s view denies time as something absolute, a natural constant of the universe. He implied that there is no objective direction of time, and we invent it based on our perception, similar to how we refer to the direction toward the Earth’s center as “down,” even though there is nothing definitive to prove that this designation is correct.
In the 20th century, doubts about the existence of time began to deepen. Isaac Newton viewed the universe as an enormous unchanging clock, marking the passage of time as an absolute intensity, something existing independently of everything else.
The great revolution in the concept of time began with Albert Einstein. In his general theory of relativity, he considered time as another dimension in the universe’s deformable structure to explain gravity. In his special theory of relativity, time also became elastic, depending on the position and velocity of the observer, making the concept of “now” meaningless.
Decades later, in a condolence letter to his friend Michele Besso’s family, Einstein wrote that for physicists, “the distinction between past, present, and future is only a persistent illusion.”
With relativity, Albert Einstein shook the very notions humanity had taken for granted about time. He demonstrated that time is constituted by matter. Time does not exist independently from the beginning; it was not created before the universe formed to wait for events to be recorded on its axis. In other words, time is relative and flows faster or slower depending on the observer. It flows slowly for an observer moving quickly and vice versa, flows quickly for an observer moving slowly.
Clearly, many events in the universe can be arranged in order, but time cannot always be absolutely divided into past, present, and future. Some physical equations may still hold true even if time runs backward. All fundamental physical equations used to describe the world do not contain any time variable.
The great revolution in the concept of time began with Albert Einstein. (Illustrative image).
Is Time Just an Illusion?
In 2018, theoretical physicist Carlo Rovelli published The Order of Time and the Emergence of Time in the Context of Thermodynamics, suggesting that time is an illusion generated by our incomplete knowledge. Time does not exist objectively.
He wrote: “Time is a concept created by humans; it is not something fundamental. We certainly have a common intuition about time, contrary to clear physical experiments. After all, perhaps time does not exist.”
He argued that time seems to flow in an orderly manner. The way Earth moves in the universe creates a sense of order for us (which would not exist on other planets), while time is merely a product of our planet’s relationship with its surroundings, rather than something inherent to the universe.
If Rovelli and other physicists believe our understanding of time is incomplete, other scientists go even further by practically asserting that it does not exist at all. This is what philosophers Kristie Miller, Sam Baron, and Jonathan Tallant argue in their book Out of Time: A Philosophical Study of Timelessness.
The existence of time remains an ambiguous question. (Illustrative image).
Kristie Miller presents the argument: “Time may not exist, but we still have causal relationships, the notion that one thing causes another afterward. And according to the authors, this is not time but a fundamental property of the universe.”
Nevertheless, the existence of time remains an ambiguous question and will certainly be a topic of debate for a long time to come.
“Discussing time is a fascinating topic because it touches on the deepest emotions within the human soul. Time opens up life and takes away everything. Reflecting on time is reflecting on the meaning of your life,” shared Italian scientist Rovelli, explaining that this is also why he dedicates his life to studying the two words “time.”
