Time might not exist.
Development in physics suggest the non existence of time, is an open possibility,
that we should take seriously.
We need not worry, because even if time does not exist, our lives will go on as usual.
Physics is in crisis.
For the past century or so, we have explained the universe,
with two widely successful physical theories:
General relativity and quantum mechanics.
Quantum mechanics describes how things work in the incredibly tiny world of particles,
and particle interactions.
General relativity describes the big picture of gravity, and how objects move.
Both theories work extremely well in their own right.
But the two are thought to conflict with one and another.
Though the exact nature of the conflict is controversial,
scientists agree both theories need to be replaced with the more general theory.
Physicist wants to produce a theory of quantum gravity,
that replaces general relativity and quantum mechanics,
while capturing the extra ordinary success of both.
Such a theory would explain how gravity’s bit picture,
works in the miniature scale of particles.
It turns out that producing a theory of quantum gravity is extremely difficult.
One attempt to over come the conflict between the two theories, is string theory.
String theory replaces particles with strings, vibrating in as many as eleven dimensions.
However, string theory faces a further difficulty.
String theories provide a range of models that describe a universe broadly like our own.
They don’t really make any clean predictions, that can be tested by experiments,
to figure out which model is the right one.
In the 1980’s and 1990’s many scientists became dissatisfied with string theory.
They came up with a range of new mathematical approaches to quantum gravity.
One of the most prominent of these, is loop quantum gravity.
The theory proposes that the fabric of space and time,
is made of a network of extremely small discrete chunks or ‘loops’.
One of the remarkable aspects of loop quantum gravity is that,
it appears to eliminate time entirely.
A number of other theories also seem to remove time as a fundamental aspect of reality.
We know we need a new physical theory to explain the universe.
This theory might not feature time.
If this theory turns out to be correct, would it mean that time does not exist?.
It is complicated, and depends on what we mean by ‘exist’.
Theories of physics don’t include, any tables, chairs or people.
Yet, we still accept that tables, chairs and people exist.
That is because we assume that such things exist at a higher level,
than the level described by physics.
We say that tables, for example ‘emerge’ from an underlying physics of particles,
existing in the universe.
While we have a pretty good sense,
of how a table might be made out of fundamental particles,
we have no idea how time might be made out of something more fundamental.
Unless we can come up with a good account of how time emerges,
it is not clear, we can simply assume time exists.
Time may not exist at any level.
Saying the time does not exist at any level, is like saying that there are no tables at all.
Managing in a world without time seems positively disastrous.
Our entire lives are built around time.
We plan for the future, in light of what we know about the past.
We hold people morally accountable for their past actions.
We believe ourselves to be agents, - entities that can take action -,
in part because we can plan to act in a way that we bring about changes in the future.
The discovery that time does not exist,
would seem to bring the entire world to a grinding halt.
There is a way out of this mess.
While physics might eliminate time, it seems to leave causation intact,
the sense in which one thing can bring about in another.
Perhaps what physics is telling us,
is that causation and not time is the basic feature of our universe.
If that is right, then agency can still survive.
For it is possible to reconstruct a sense of agency, entirely in casual terms.
The discovery that the time does not exist, may have no direct impact on our lives,
even while it propels physics into a new era.