Does time exist? The answer to this question seems obvious: Of course it is! Just look at the calendar or the clock.
But the development of physics shows that the non-existence of time is an open possibility and we should take it seriously.
How is that possible, and what does that mean? It will take some time to explain, but don’t worry: even if time does not exist, our lives go on as usual.
A crisis in physics
Physics is being in crisis. Over the past century or so, we’ve explained the Universe using two extremely successful physical theories: general theory of relativity and quantum mechanics.
Quantum mechanics explain how things work in the infinitely small world of particles and interactions between particles. General relativity gives an overview of gravity and the way objects move.
Both theories work too well, but the two are said to contradict each other. Although the exact nature of the conflict is disputed, scientists usually agree that the two theories should be replaced by a new, more general theory.
Physicists wanted to come up with a theory of “quantum gravity” that would replace general relativity and quantum mechanics, and capture the phenomenal success of both. Such a theory would explain how the big picture of gravity works on the miniature scale of particles.
Time in quantum gravity
It turns-out that creating a theory of quantum gravity is extremely difficult.
One attempt to overcome the contradiction between the two theories is string theory. String theory replaces particles with strings that vibrate in 11 dimensions.
But string theory faces another difficulty. String theories give a wide range of models that explain a universe as wide as ours, and they do not really make definite predictions that can be tested with experiments to determine the model which is correct.
During the 1980s & 1990s, many physicists became not satisfied with string theory and came-up with a series of new mathematical approaches to quantum gravity.
One of the greatest important of these is looping quantum gravity, which introduced that the material of space & time is made-up of a network of tiny discrete chunks, otherwise known as “loops”. “
One of the amazing things about loop quantum gravity is that it seems to eliminate time entirely.
Loop quantum gravity isn’t the mere way in astonishing time: several other approaches also seem to eliminate time as a fundamental aspect of reality.
So we know we require a new physical theory to describe the Universe, and that theory might not be related to time.
Suppose such a theory turns-out to be true. It follows that time does not exist?
It is complex, and it depends on what we mean by existence.
Physical theories do not include any tables, chairs, or people, but we still accept that tables, chairs, and people exist.
Why? Because we suppose that such things exist at a higher level than that explained by physics.
We say that the tables, for instance, “emerge” from a particle physics whizzing around the Universe.
But while we have a very good idea of how a table can be made of fundamental particles, we don’t know how time can be “made up of” anything more fundamental.
So, unless we can come up with a good description for how time comes emerges, it’s not clear that we can only assume that time exists.
Time may not exist at any level.
Time and agency
To say that time does not exist on any level is like saying that there are no tables at all.
Trying to manage in a world without tables can be difficult, but managing in a world without time can seem disastrous.
Our entire life is built on time. We plan for the future, based on what we know from the past. We hold people morally accountable for their past actions, in order to reprimand them later.
We see ourselves as agents (entities that can do things) in part because we can plan to act in ways that will cause change in the future.
However, what good is action to bring about change in the future when, in a too real sense, there is no future to act on?
What good is it to punish someone for a past action, when there is no past and therefore, it seems, no such action?
The discovery that time doesn’t exist would seem to immobilize the world. We will have no reason to get-out of the bed.
Business as usual
There is a way out of trouble.
Although physics can eliminate time, it seems to leave the same causality: consciousness in which one thing can bring-about to another.
What physics is telling us, is that cause and effect, not time, is a basic characteristic of our Universe.
If that’s true, the agency could still survive. Because it is possible to rebuild a sense of agency entirely in terms of causal terms.
At least that is what Kristie Miller, Jonathan Tallant and he argue in their new book.
They suggest that the discovery that time doesn’t exist may not have a direct impact on our lives, even if it propels physics into a new era.
This article have been originally published from The Conversation.