Time Does Not Exist

October 18, 2008 – The next time you tell someone, “I don’t have time,” rest assured, you are telling the truth. We humans are obsessed with “time,” but does time even exist?

By The Cerebral Aesthetic Vagabond

Hot on the heels of my post titled If I Could Live In Any Place And Time, I have a most unfortunate confession to make: it’s not possible to travel back to a preferable point in time because time itself does not exist! I can forgive people for having an immediate impulse to dismiss this entire post as the babbling of a lunatic and stop reading. After all, our entire existence revolves around the concept of “time.” Just try uttering a single sentence without referring to time: “today I’m going to ...”; “call me later”; “when I was ...”; “how long will it ...”; and so on. Time is so innate, ingrained, and intuitive to our thought processes that we don’t even give it a second thought.

But just because our minds depend on the concept of time to help us think, does that make time real? It’s been claimed by some that lower animals do not perceive time, or at least do so with far less discrimination than humans. Some claim that the human capacity for perceiving time has to do with our sophisticated memory, which certainly seems like a prerequisite for perceiving time. After all, a huge chunk of what we perceive as time, the past, is only made possible by memory. Without a good memory the past is inconceivable. A rich collection of memories, however, could actually be a mentally debilitating liability without some means to categorize those memories and make some sense of them. Chronological ordering is certainly a useful way to categorize memories, thus necessitating the concept of time. Animals that don’t possess such rich memories or engage in complex mental analyses may not require the concept of time. It definitely seems to be the case that the lower orders of life are governed less by thinking and more by “programming.” Insects, for instance, are totally controlled by programming, largely directed by the release of chemical pheromones. Insects have absolutely no need for the concept of time.

I submit that time is merely an aid to thought, required only by humans.

Universe As A Giant State Machine

Every individual atom in the universe represents a tiny state machine, the positions and vectors of all its subatomic particles defining its state at any given point in “time.” (I’m afraid I’m going to have to use the word “time” throughout this essay because human thought is impossible without it. However, what I really mean by “point in time” is “state X,” one state in an infinite sequence of distinct states. I’m also not going to take into account quantum physics because, frankly, I don’t know enough about it to talk about it intelligently. So please bear with my simplistic view of atoms.) Each individual molecule also represents a state machine, slightly more complex, defined by the arrangement of its atoms and their individual states. Finally, the entire collection of molecules and atoms in the universe represents a single, giant, extraordinarily complex state machine.

Any change of state, even at the subatomic level shifts the entire universe to a new state. However, at any given point in time, there is still just one universe and it’s still in just one state. Granted, this universal state machine progresses through state changes at an unfathomable pace, but each state is still distinct, if only for an infinitesimal moment.

(I am aware that my simplistic view of the universe is at odds with theories such as the Many-Worlds Interpretation of Quantum Mechanics, the essence of which seems to be that each subatomic state change actually produces a whole new parallel universe, if I correctly understand the theory. According to MWI, a single atom can thus be in multiple states at once, each in its own parallel universe. While I find MWI too abstract for me to grasp and it defines an infinitely more complicated universe than my “simple” one, it’s not incompatible with the fundamental argument presented in this essay, which is that time does not exist.)

Time Does Not Exist

The simplest proof I can offer that time does not exist is this little thought exercise. Imagine if every atom in our universal state machine (including all the MWI parallel universes) were instantly frozen in place and not allowed to move. The universe could be held in that state indefinitely and it would be impossible to ascertain how much “time” had elapsed. When the universe was allowed to resume its movement, whether one second or one million years later, everything would continue where it left off, nobody the wiser. For people who play video games, think of it like pausing the game. You can walk away for a minute or an hour and the game resumes from where it was paused. Therefore, since time cannot be measured while the universe is in this suspended state, time does not exist as a physical, measurable property. Time is merely an illusion, a thought aid for our complex human minds.

Consider the ways we measure time. A sundial is an ancient timepiece that uses the movement of the sun to produce a positional change of a shadow upon a graduated surface; an hourglass reports the movement of a finite number of grains of sand from one globe to another; a mechanical watch or clock reports the movement of hands from one place to another. All these timepieces measure not time, but movement, in other words, changes of state.

Analog clock
The movement of the hands on the watch from one position to another is merely a proxy for the passage of “time.” As a charming “proof” of my frozen universe argument above, it took me several minutes to photograph the watch pictured above. However, the battery in the watch is dead, so the hands did not move; in other words, they were frozen. Consequently, it was not possible to ascertain that any time had elapsed because the hands were frozen. If I replace the battery, unfreezing the watch, it will resume its advance from the point where it was frozen as if nothing had happened, and it will be impossible to ascertain how long the watch had been frozen.

Suppose you could speed up or slow down the rate of state changes taking place in the entire universe. Would it be possible to measure the speed of the universe with the above timepieces? No, because everything would be accelerated or decelerated by the same amount. The shadow would move across the sundial “faster” or “slower,” but so would all other state changes, making the altered rate of state changes impossible to discern. Since the rate of state changes in the universe cannot be discerned, then the notion of “rate of change” is meaningless, and therefore so is the notion of time itself.

By way of example, let’s say that using a standard mechanical watch in a universe running at “normal” speed, in the time it takes us to walk from our house to the park the hour hand moves from the 12:00 position to the 1:00 position. We would say that one hour had elapsed. In fact, what physically happened is that the hour hand moved one-twelfth of the way around a circular dial. We impart meaning which we call “time” to that physical change of state. Now let’s say that we somehow slow down the universe so that everything moves half as fast. How long would it take now to walk from our house to the park? Well, the watch would move half as fast, so it would actually take two hours for it to move from 12:00 to 1:00, but it would also take us twice as long to walk from our house to the park. The resulting state changes in both our position and the position of the watch hands would be identical, even though the universe was running at half speed! In other words, there is no way for us to measure the true “speed” of time, and therefore time must not exist.

In fact, here is the “official” definition of the unit of time we call a second:

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.

Notice the words “periods” and “transition” in the definition. A second is defined as a specific number (“periods”) of state changes (“transitions”) of a particular atom (cesium 133). In other words, if it takes me one minute to walk from my office to the kitchen, according to this definition it doesn’t really take “one minute”; it takes 5.5 x 1011 state transitions of a cesium atom. Thus, I can describe how “long” my journey takes without any reference to “time.”

All of our timepieces, including the sophisticated “official” definition of a second are actually devices that count state changes, not elapsed time. We humans are the ones who attach the notion of time to these state changes.

Why We Sense Time

As I said above, time is a convenient tool for thinking. It’s cumbersome to say I saw my friend 7.9 x 1014 cesium 133 state transitions ago. It’s far easier to say I saw my friend yesterday. Time is a handy tool for some of our laws of physics and mathematics, although if we tried we could probably come up with alternative laws that didn’t involve time. Time enables us to categorize our memories into a useful chronological order, which may help us to understand cause and effect. Consequently, it may also help us to anticipate the future by analyzing present actions in the context of the cause and effect observations of the past. I suspect the concept of time plays an crucial role in such complex thought processes.

How We Sense Time

So if time does not exist, then how do we sense time? Well, since time can be alternatively thought of as the ratio between the number of state changes of different phenomena, perhaps we have built into our heads a little bioelectrical or biochemical metronome which we use as a reference. Such a mechanism is not as absurd as it sounds, as birds have a magnetic compass in their heads which aids their navigation.

So imagine that this internal metronome ticks at a particular frequency, then what we perceive as elapsed time is really our sensation of the number of ticks of this internal metronome. For example, let’s say you walk from your house to the corner store and it takes 1,000 ticks of your internal metronome. Now let’s say you walk from your house to the local park and it takes 1,500 ticks. You would conclude that it took 1.5 times as long to walk to the park as to the store, but is the concept of time actually necessary to arrive at this conclusion? No, all that has really occurred is that in the first case the metronome underwent 1,000 state changes and you underwent one principal state change, from your atoms being at your house to their being at the store. In the second case, your state changed from being at your house to being at the park and the metronome underwent 1,500 state changes. In other words, while time is a useful thought construct, it is not necessary to describe what happened to the state of the universe. Of course, in this example I’m overlooking the virtually infinite number of tiny state changes that occurred in between the major ones.

It’s possible that our brains automatically compare the number of state changes that occur in our built-in metronome with the state changes occurring outside the brain, and synthesize a sensation of elapsed time. What we sense in our minds is elapsed time, when in reality what our brain is measuring is the relative numbers of state changes. Such a hypothesis could also explain why other animals might lack a sense of time: they lack this built-in metronome. It might also explain why some people seem to operate on a different time basis than others: their built-in metronome operates at a different rate from that in other people.

Time Travel

Your average person probably believes time travel is possible, if only the proper piece of equipment could be devised, like that in the movie The Time Machine. Some people may even believe that time travel has actually been accomplished. Now I’m going to say something that sounds contradictory: I believe time travel is possible in theory but impossible in practice.

Traveling back in time is possible in theory by rearranging all the atoms in the universe to their exact same state in a previous “time.” Once so rearranged, the universe would continue more or less along the same trajectory as before, ignoring the random quantum variations which might over the long run produce a vastly different future state. Yet despite being conceptually graspable, this approach to time travel is obviously impossible in practice. Just recording the state of each individual atom in the universe would require at least as many atoms as there are in the universe, so how could we possibly restore the universe to any prior time? We lack the means to even record, and thus know the state of the universe in any single past time, let alone an infinitude of past times.

It would be negligibly more feasible to change the state of a portion of the universe to that of a previous time, for instance, the state of just our solar system. But even in that limited case the rest of the universe would remain in its present state, Since events on Earth are influenced by happenings outside our solar system, and since those external portions of the universe would not have been altered, it’s safe to assume that events on Earth would diverge even more quickly from the historical record, owing to the external influence of the rest of the universe. However, for a brief moment, the Earth might be “back in time.”

While time travel through the process of rearranging all the atoms in the universe is theoretically possible, it’s not just you that would be going back in time, as depicted in the movie mentioned above. The entire universe would go back in time! The present would cease to exist because there is only one set of atoms and they can only be in one state at a time (MWI notwithstanding). Once those atoms are rearranged from their present state to some past state, the present would be gone.

Traveling in time to the “future” makes no conceptual sense at all because the future has never existed as a discrete state, unlike the past. Any “future” state we might wish to visit will be one we have to fabricate ourselves from our own imagination. In fact, we’re constantly creating the future with every single state change we introduce into the universe.

Conclusion

Obviously, the concept of time is a necessary and useful one for us humans. My purpose here is not to disabuse people of the concept of time, but to open their eyes to a different way of looking at the universe, as a giant state machine in which time is utterly irrelevant and unnecessary. If one examines physical phenomena fundamentally enough, it becomes apparent that most can be explained without the concept of time.

Update – 23 June 2009

I ran across an interesting new article describing The Biocentric Universe Theory, which asserts that not only is time a manifestation of the mind, but so is space. The part that is relevant to my essay here is this sentence which concisely conveys the essence of my essay:

According to biocentrism, time does not exist independently of the life that notices it.

It does make some intuitive sense to me that space is subject to perception, just as is time, but without giving it more thought it’s difficult for me to conceptualize.

The End