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Monday, November 10, 2008

Time and the nature of now

Time is short. Now is the time. Father Time. We have lots of time.


I have been thinking a few years now about the nature of time. In particular, what is now? As I write this, it is 3:26 pm, and it is the present. Now it is 3:27 pm, and time I wrote the prior sentence is now in the past, and this is the present. What happened? What changed to make the present into the past? How does the future become the present (and then the past)?

The world could be like a old time movie reel. The whole story is actually already filmed, and in a can. The characters in the plot don't know they are in a movie, as each frame is displayed, they experience a "now", and have the illusion of free will - the ability to make decisions, and see the results. But since the future (the frames yet to be shown) is just as real as the past (the frames that have already been shown), their sense of freedom of action is not real, from the viewpoint of a "super-time" resident outside of the can. In Christian terms, this is a form of Calvinism, as practiced by Presbyterians and Baptists (although most don't know that is their doctrinal belief) - a belief where the future is fixed, and some are born to be saved, while some are born to be damned. I suspect Islam has similar view - "God's will be done", but I'm not as familiar with Muslim thought.

In physics, there are lots of equations that include "t", standing for time. Some don't, for example "F=MA", Newton's 2nd law, which says that a force acting on an object of mass "M", will create an acceleration in equal proportion. No time there, except as implied by acceleration, which is the rate of change of velocity over time. but extending the concept gives us "v=u+at", which says that if you apply an acceleration over a time period ("t"), you will get a change in velocity in addition to the starting velocity ("u"). So "t" is a range of times, say 10 seconds.

It doesn't say if that 10 seconds was last week, 3 billion years ago, or 2 years in the future. It doesn't say "the time between 09:10:23 EST on Tuesday October 7th, 2008, and 10 seconds after that". These equations (and all others in physics that I have ever seen) take no regard of the present (or past, or future), only a period of time, indistinguishable from any other, and to an observer in the same inertial frame of reference (nod to Einstein and relativity), always passing at the rate of 1 second per second, 60 seconds per minute, 60 minutes per hour, 24 hours per (Earth) day.

I think we get the closest to an answer from quantum mechanics. Heisenberg's uncertainty principle says that that for a particle, the values of position and momentum, cannot both be known with precision. The more precisely one variable is known, the less precisely the other is known. This is not a statement about the limitations of a researcher's ability to measure particular quantities of a system, but rather about the nature of the system itself. In other words, nature itself is fuzzy, and it takes a conscious act of observation (measurement) to resolve the fuzziness, but the more you know (or tune in to) about one attribute, the more fuzzy (out of tune) everything else becomes. It's not just you - the universe is actually itself "fuzzy".

The Universe (at a quantum level at least) is unresolved until an observer measures it. By measuring, I don't mean with a yardstick or scales - simply seeing or feeling something is enough. Schrondinger's cat illustrates this nicely (http://en.wikipedia.org/wiki/Schrodingers_cat). Schrodinger envisaged an experiment, where a macro event (whether a cat lived or died) is tied to a random quantum event, such as the decay of an unstable radioactive atom. According to quantum theory, the cat is both dead, and alive at the same time, until the experimenter checks to see if the cat is alive or dead, at which point the quantum uncertainty collapses into one of the two possible states, and we know that the cat either lives, or is dead. Leaving aside all the cosmological interpretations of this (e.g. Everett's Many Worlds theory, vs. the Copenhagen (just follow the math) interpretation), this might start us on the road to understanding what is Time, and what is Now.

I think Now is best defined as "the moment the quantum uncertainty is resolved through observation". I don't think it necessarily means that this Now is any different from all the other "nows". Our conscious brains give the illusion of things happening in a particular way and order, but it is more like the movie reel - only one frame is the Now, but all the other frames are equally valid and imminent.

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