February 21, 2013
Raymond Tallis: Time's arrow
Raymond Tallis at the website of the Institute of Art and Ideas:
While most philosophers of time would be content to abandon the notion that time “flows”, “passes” or “moves”, the idea that time has a “direction” is more adhesive. Insofar as it is a consequence of the conception of time as a fourth dimension on a par with the three of space, it should, like flow , etc be incompatible with it. After all, the spatial dimensions do not have a direction. Collectively the spatial dimensions are the possibility of direction, just as they are the possibility of movement. Clearly, the direction of time – or the possibility of its having a direction - could not be provided by space. It would not make sense to say that time was pointing from left to right or up and down.
But there is something else, which is absolutely central; namely that the unfolding of time appears to be one way. This is in contrast to any direction in space – or any line marking a direction or trajectory in space. The line from A to B is also from B to A; any path going from a lower point to a higher point is also a path going from a higher point to a lower point. The apparent absence of this reversibility is all that there is to the direction of time. The link between earlier time t1 and later time t2 can be traversed in one direction- earlier-to-later – but not in the other direction – later-to-earlier. The path from t1 to t2 is inescapable while the path from t2 to t1 is blocked.
The hunt has therefore been on for something that will give time a direction in this very restricted sense of moving “forward” but not “backward”. This something will account for the difference between time and its spatial companions, a difference that will account for the fact that we can wander at will in space but not in time.
More here.
Posted by S. Abbas Raza at 06:57 AM | Permalink
Comments
Lubos Motl gives a far more rigorous demonstration here:
http://motls.blogspot.com/2013/02/ludwig-boltzmann-birthday.html
Hard to understand for the uninitiated, granted, but it all rooted in probability. Time flowing backwards, even for a tiny instant in a tiny region of space, is so vanishingly small that you would have to wait longer than the age of the universe to see it happen, at least outside a movie theatre.
Posted by: Luke Lea | Feb 21, 2013 10:42:47 AM
I question the final phrase of Mr. Stallis's assertion: "Memory is the accumulation of information; information is increased entropy; the increased entropy of our brains . . ."
As we store particular bits of information in our brains in the form of memories the entropy of the brain decreases, just as the entropy of a living organism decreases as it develops from an egg -- made possible from the energy flowing from the sun. The total entropy of the organism and its surroundings increases, but not of the organism itself. Likewise in the case of the brain. I may be mistaken about this though. I am hardly an expert.
Posted by: Luke Lea | Feb 21, 2013 11:31:28 AM
Clarification: the total entropy of the brain decreases in the sense that it becomes more ordered. Order is the inverse of entropy. A disordered state requires more information to describe, but the information required to describe an ordered state, while less, .is more useful.
Isn't this clearer than Mr. Stallis's long-winded discussion. If you are going to be long-winded do it Motl's way: with math.
Posted by: Luke Lea | Feb 21, 2013 11:36:00 AM
Clarification of my clarification, made necessary because my middle comment failed to post. In it I took issue with Mr. Tallis's assertion that as a brain stores information in the form of memories its entropy increases. I think it decreases and for the same reason that the entropy of a living organism decreases with time: it absorbs energy from the environment, ultimately from the sun. The total entropy of the organism (or brain in this case) together with its environment increases due to metabolism, so there is no violation of the second law of thermodynamics.
I am not a professional theoretical physicist however, merely an amateur, so I could be mistaken on this point. Ask Lubos, I am sure he can give an authoritative answer.
Posted by: Luke Lea | Feb 21, 2013 12:45:47 PM
@luke
Did you even really read the full article? Tallis systematically undermines the position you maintain he holds. Retread the last paragraph in the linked post.
Posted by: Gene | Feb 22, 2013 12:01:31 PM
Hi Gene, please elaborate
Posted by: Luke Lea | Feb 22, 2013 12:38:46 PM
He's saying that if we employ a metaphor, here Time's Arrow, to guide our thinking about time that we will end up making contradictory statements. Shannon and Weaver, the first to give a firm definition of information, were explicit that it referred to the message and not to message interpretation. So, when we use the word information we either fail to use it in the limited sense or muck things up by conflating it with older senses of the word. Same with entropy more or less. IOW, when we try to locate our experience of time in frameworks that exclude "our" side we can't help but get nowhere or in his sense "no-when." He's not saying the problem is with information science or the 2nd law of thermodynamics but with the limitation of the metaphor. BTW, his is an old observation as Gustav Fechner, the founder of the field of experimental psychology, made a similar observation a 150 years ago. He said that any living system with enough complexity has an interiority that is as basic as its material substrate and science would do well to not exclude it. Because hardly anyone listened we have a Tallis trying to reorient our basic attempts to understand time, temporality & event-ualty. The post is a part of his new book which won't come out to 2014. We'll unfortunately have to wait until then to see if this promising start is something really new, a re-presentation of older views or as you might have it just a lot of wind.
Posted by: Gene | Feb 22, 2013 1:31:59 PM
Thanks, Gene. I rest my case.
Posted by: Luke Lea | Feb 23, 2013 11:57:52 AM
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