On Time (Pt.I)

St. Augustine (354 - 430 A.D.) wondered in his Confessions about the nature of time. He wrote that "As long as nobody asks me I know perfectly well what time is, but as soon as I'm asked to explain it I haven't the faintest idea".

Philosophers and scientists ever since have sympathized with Augustine's perplexity. Time has been called one of the universe's greatest mysteries and no one really knows what it is.

John Steele, the publisher and editorial director of Nautilus puts some questions about time to physicist Paul Davies. In an interview for Nautilus Steele asks Davies the following:

• Is the flow of time real or an illusion?
• So where does this impression of flow come from?
• Is time fundamental to the Universe?
• So time could be emergent?
• If multiple universes exist, do they have a common clock?
• What do you think are the most exciting recent advances in understanding time?

Davies' answers to most of these questions amounts to an admission of scientists' ignorance on the topic, but his answer to the first question is interesting. He replies:

The flow of time is an illusion, and I don’t know very many scientists and philosophers who would disagree with that, to be perfectly honest. The reason that it is an illusion is when you stop to think, what does it even mean that time is flowing?

When we say something flows like a river, what we mean is an element of the river at one moment is in a different place of an earlier moment. In other words, it moves with respect to time. But time can’t move with respect to time—time is time. A lot of people make the mistake of thinking that the claim that time does not flow means that there is no time, that time does not exist. That’s nonsense. Time of course exists. We measure it with clocks. Clocks don’t measure the flow of time, they measure intervals of time. Of course there are intervals of time between different events; that’s what clocks measure.

Davies is saying here that the flow of time is an illusion like the apparent movement of the sun across the sky is an illusion. It's we who are moving, not the sun. Likewise, on Davies' view, sometimes called the static view of time, every moment of time, every event, past, present, and future exists now, and somehow our consciousness moves from one to the next.

On this view, the universe is like a movie that has been instantaneously burned onto a DVD. Every event in the movie exists simultaneously with every other event, but the characters in the movie, and even the person viewing the movie, perceive those events as happening sequentially.

If this is true then it would seem that time does not exist "out there" but is rather somehow a feature of our minds. It's the way our minds apprehend events.

I'll have more to say about this tomorrow.