What if time didn’t exist? In our daily lives, everything seems governed by an implacable mechanism: a day lasts twenty-four hours, the seconds tick by without anything being able to hold them back, giving our life a sensation of inexorable movement forward. However, certain theories in quantum physics overturn this fundamental intuition. They suggest that time could be an illusion, a useful concept, certainly, but without a reality of its own.
To understand this dizzying idea, we must first recognize that we never measure time directly. We simply observe changes in different systems. In the past, the course of the Sun and the Moon served as a reference: their position dictated the times of day and night. Today, scientists use ultra-precise instruments, such as atomic clocks, which count the oscillations of an electron around an atom. In other words, what we call “time” is only the evolution of another physical reality, that of our own knowledge and our tools.
An article from Popular Mechanics takes the example of a car circuit. A car spins around the circuit, while a hand holding a stopwatch marks each lap. In practice, we could describe the entire race by a simple table of correspondence between the positions of the car and those of the number indicated on the stopwatch, without ever needing to involve the variable “t”, symbolizing time. The stopwatch reads 36, so the car has completed 36 laps.
This idea takes on an even more interesting dimension in quantum physics. In this field, physicists study changes in the state of particles on an infinitesimal scale. In 1983, researchers Don Page and William Wootters proposed a bold concept: time could emerge from a phenomenon called “quantum entanglement,” a deep correlation between the system being studied and the clock that measures it. According to their approach, the dynamics of a system would result from this entanglement, even if the overall state of the universe remains perfectly still.
A simple impression of continuity
This hypothesis is dizzying: each moment of time would correspond to a distinct universe. Moving from the present to the future would simply mean moving from one universe to another in this infinite whole. This shift brings us back to the experience of the famous Schrödinger’s cat, simultaneously alive and dead by the effect of entanglement. Being in a universe where the cat is alive or in one where it is dead would be equivalent to existing in two different moments of time.
If time is an illusion, the past and the future would therefore coexist with the present. No moment would be special or to be privileged over the other. The river of time would not carry us forward as we mentioned at the beginning of the article; our consciousness would simply correlate successively with the different states of the universe. The impression of continuity that we feel on a daily basis would only be a perception effect within an immense set of entangled states.
Albert Einstein shared this peaceful vision of time. In a letter addressed to the wife of his friend Michele Besso, after the latter’s death, he wrote: “For those who believe in physics, the distinction between past, present and future is only an illusion, however tenacious it may be.” The genius saw this as a consolation: in this timeless universe, nothing really disappears, everything coexists in a vast set of possibilities.
But if the universe is truly timeless, what new explorations are open to physics? Some researchers imagine that by subtly manipulating the quantum clock of the universe, we could influence its dynamics itself. This idea, still highly speculative, suggests that the fundamental laws are not fixed. They could be reprogrammed depending on how we interact with the timeless structure of the cosmos. Understanding nature could, finally, mean truly taking control of it.
