Monday, December 5, 2011

Going Forward, Not Standing Still: On the Arrow of Time, Entropy and Growth

I happened to be flipping through the TV channels and I saw a documentary by Brian Greene called The Elegant Universe  (if you're interested you can watch it for free online...though be careful because of the many errors he makes by trying to reach a large, public audience.) In particular, he states that the laws of physics are the same forward as backwards, i.e. that the laws of physics are time reversal symmetric. While three of the forces of nature are time reversal symmetric, the weak nuclear force is not time symmetric. And this force is most likely the cause of the arrow of time that we see in the real world.

But this is not a new fact. The lack of time reversal symmetry has been known since the 1960s, and Brian Greene would have studied this multiple times in life. But it's not only Brian Greene who repeatably makes this mistake; in a previous post, I discussed how Sean Carroll of CalTech makes the same mistake. Another physicist in the same boat is Julian Barbour, who wrote a book in 1999 called "The End of Time." This book, which I've only skimmed, suggests incorrectly that there is no such things as time and hence, no such thing as history, because the equations of motion of time reversible (which they are not, and as already stated above, this has been known since the 1960s.)

Why do so many smart people ignore the time asymmetry of the weak nuclear force and continue believing that there is no such thing as time or history?

It really makes me think that there must just be some people out there who prefer thinking that the world is time reversal symmetric because it falls inline with their philosophical beliefs...it's almost a statement that if there is no arrow of time, then there is no such thing as progress. That growth is an illusion. It appears that there are some people, like Brian Greene, Julian Barbour or Sean Carroll, who prefer thinking that there is no difference between the past and the future. This is basically a philosophy of nihilism, i.e. that there is no meaning to life.



What I find so hilarious is that many physicists and astrophysicists think that they are better than religious believers because they are willing to live with the meaningless of the universe...that they are better than other people because they can shoulder this burden.

But there's no burden because these physicists are basing their philosophy (of timelessness) off of out-of-date physics. As I've stated above, it's been known for over 40 years that the laws of physics are not time reversal symmetric. And since Prigigone's work in the 1960's and 70s, we've known that lifeforms are dissipative structures that consume exergy, do work and generate entropy without violating any of the laws of thermodynamics. There is a clear arrow of time. It's not an artifact; it's not a trick that the human mind is playing on. There is a very real difference between the future and past. The entropy of the future is always greater than the entropy of the past. And although it's hard to see at the macro-scale, the universe is actually becoming more symmetric.

The questions remaining in my head are:  why do some people want the world to be timeless? i.e. without past or future?  why do some people (like the one's I've mentioned above) want the world to be timeless so badly that they are willing to ignore well established results? And worse, why would they write a book or make a documentary about the "timelessness of the universe" if they really believed that the world was without past or future?  (Why would they get out of bed each morning? What would be the point of their life? Why would they spend so much time doing physics if there were no meaning to life?)  Somehow, I'm guessing that Brian Greene, Sean Carroll and Julian Barbour don't really believe in the "Timelessness BS" that they are promoting. These are all really smart people who have each made meaningful contributions to their fields of study. I'm guessing that they are just drawn to the simplicity or the symmetry of the equations, and haven't thought through the ramifications of their philosophy of "timelessness."

Luckily, the facts aren't on their side, and there is a meaning to life that is consistent with today's understanding of the laws of physics...that the goal of life is for life to grow and expand. So, I'd like to end this post with a quote by the narrator of Dostoevsky's Notes from the Underground...


"Perhaps the only goal on earth to which mankind is striving lies in this incessant process of attaining, in other words, in life itself..."

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