Does time exist?

One of the remarkable aspects of loop quantum gravity is that it appears to eliminate time entirely.

Loop quantum gravity is not alone in abolishing time: a number of other approaches also seem to remove time as a fundamental aspect of reality.

Emergent time

So we know we need a new physical theory to explain the universe, and that this theory might not feature time.

Suppose such a theory turns out to be correct. Would it follow that time does not exist?

It’s complicated, and it depends what we mean by exist.

Theories of physics don’t include any tables, chairs, or people, and yet we still accept that tables, chairs and people exist.

Why? 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 whizzing around the universe.

But 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.

So unless we can come up with a good account of how time emerges, it is not clear we can simply assume time exists.

Time might not exist at any level.

Time and agency

Saying that time does not exist at any level is like saying that there are no tables at all.

Trying to get by in a world without tables might be tough, but 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, with an eye to reprimanding them later on.

We believe ourselves to be agents (entities that can do things) in part because we can plan to act in a way that will bring about changes in the future.

But what’s the point of acting to bring about a change in the future when, in a very real sense, there is no future to act for?

What’s the point of punishing someone for a past action, when there is no past and so, apparently, no such action?

The discovery that time does not exist would seem to bring the entire world to a grinding halt. We would have no reason to get out of bed.

Business as usual

There is a way out of the mess.

While physics might eliminate time, it seems to leave causation intact: the sense in which one thing can bring about another.

Perhaps what physics is telling us, then, is that causation and not time is the basic feature of our universe.

If that’s right, then agency can still survive. For it is possible to reconstruct a sense of agency entirely in causal terms.

At least, that’s what Kristie Miller, Jonathan Tallant and I argue in our new book.

We suggest the discovery that time does not exist may have no direct impact on our lives, even while it propels physics into a new era.

Sam Baron, associate professor of philosophy, Australian Catholic University.

This article is republished from The Conversation under a Creative Commons licence. Read the original article.

Article source: https://www.theweek.co.uk/news/science-health/956460/does-time-exist