More on Time

Last night I had a couple things running through my mind and they came together into one idea that had a bearing on a previous post - the one on Time and Time Travel. I read a little while ago about someone who was able to solve every possible game of checkers. that reminded me that back when I was in 10th grade, Stan Chase and I sat inthe back of our math classroom and worked out every pssible combinations of moves for tic-tac-toe. (Since the corners and sides are equivalent in tic-tac-toe, the number of unique combinations is pretty small.) The number of possible checkers board positions is 10 with 20 zeros, whcih is a pretty big number and much more money than I have in my bank account. It took 18 years to "solve" this puxzzle. (I find it interesting that I read about this in a Web site called NewScientistTech. Exactly when did solveing all board positions of a gasme become science? More o nthat later.)

What does this have to do with time? One of the examples people use for the "direction of time" is the movie analogy. When I was a kid, my Dad filmed one of my brothers climbing out on a swing set, hanging for a few seconds, pulling his legs through his arms in a move we called 'skin the cat,' and then dropping to the ground. We owuld always run the movie backward at that point and my brother would spring from the ground, flip over and cach the bar. It was obvious that the movie was played backwards. In some peoples minds, that shows that time has a direction.

Not so fast, if you filmed a game of checkers (see the connection now?) and played it backwards, you would know that it was played backwards. owever, there is no time associated with checkers, only a series of sequential moves. The rules of checkers allow you to determine a direction. If we came up with a new version of checkers with the following rules:

1. Start with the checkers in a random position - red on red squares and black on black squares.
2. Pieces can move any direction.
3. When you "jump" another piece, the pieces stay on the board.

Besides being a pretty stupid game, I submit that a movie of this game could be shown backwards and forwards and you could not determine which was which. So the set of interations along with some rules of interaction give the illusion of time.

Again, there is no time, it is a human invention.

Intelligent Designer

I was working on the next step in the Physics of Hope - a discussion of hierarchy and how it "falls out" from the nature of change. I still have some things to work out on that so I thought I'd take a few minutes to put down some of my thoughts on Intelligent Design.

Where does Intelligence Design leave us? We have some intelligent agent who set up a universe with certain “laws of nature” and a certain initial state that lead to the evolution of the universe as we see it today. (I’ve been trying to avoid the “e” word and I’ll get to a discussion of evolution as a universal mechanism in a future post.) We know enough to understand that if some of the basic parameters of the universe were different (like the strength of gravity, for example) then the universe would not support life. You could almost imagine that perhaps this intelligent agent had designed other universes that did not create life or humans and that was so disturbing that another universe needed to be created. (What happened to the other, non-interesting universes?) Although it is incredibly disturbing to me and runs counter to my religious education, the conclusion to make is the our Intelligent Designer is an experimenter; a curious, pencil-headed geek wearing what ever passes for a pocket protector in their existence with nothing better to try out different laws of natures and initial conditions to see which ones lead to “interesting” universes. (A universe that is interesting to the Intelligent Designer, at least.) Even worse (to me), the most plausible explanation of the universe is as some sort of computer game or simulation.

Does this mean that there was some purpose in setting up the laws of nature? It looks like there might be an overall design to the universe, but does it filter down to humans? I’ve read countless pieces that have someone looking back at their life and the “road” they have traveled. (I’ve did this just the other day, in fact.) When I looked at the decisions I made and how it “pushed” me in a specific direction. (This included where I went to college, who I married, when I had children, etc.) It is tempting to look at the improbability of knowing how a decision made 20 years ago could have had such a dramatic effect on my life today and conclude there must be guiding force to my life. So I replayed my life, in my mind, and changed one of the decisions I made so guessed where it would have lead me. I imagined myself at my age looking back at that decision and wondering how remarkable it was that I was in the place I ended up by making that different decision. Then I realized that no matter which choice I had taken at any of the forks in the road, I would always end up at a place where I would marvel at how I got there. It’s like Buckaroo Bonzai says, ‘No matter where you go, there you are.” (I wondered how I would ever get that quote into one of my writings!) It’s a miracle and improbable that you got to where you are, but the miracle is that you got anywhere at all. The path was not foreseen, and could not be foreseen, but it is miraculous none the less.

If there is any consolation in the idea that we are living in a computer game it would be as a way to explain the existence of miracles. Our Intelligent Designer could decide to “tweak” thinks during the simulation run to see how these humans will react. Now if only there were a way to tap into the psyche of this Intelligent Designer and through exhortations or prayer get them to intercede on our part. Mind you, since the universe is non-computable, even our Intelligent Designer would have no way of knowing how the intervention will come out. So who’s to say that one intervention (save the life of my child) is better than some other intervention (or no intervention). Since no one has ever been able to document or replicate a Devine Intervention, perhaps we’re better off without?

Paradoxes

On the heels of the previous post on time travel, I wanted to make a quick post talking paradoxes since time travel always comes with paradoxes.

What do we make of time travel paradoxes? Like the one where you go into the past and murder your grandfather. (Why so gruesome? You’d get the same effect if you married your grandmother before your parents were conceived, and the weirdness would be ever some much greater. Then you could be your father’s father and your own grandfather which is much odder than a being a cold blooded murder and more likely to keep you out of prison.)

I suspect paradoxes exist solely because the theories that suggest them are flawed. It could also be that some paradoxes are part of the lack of completeness (like we saw in the posting on atheism) but I suspect most are the result of wrong assumptions and wrong theories.

Let's look at one of the more famous paradoxes - Zeno’s paradox. Zeno made the analysis that if you shoot an arrow towards a target then before it can hit the target it first needs to go half way to the target. The after it goes halfway, it needs to go half of the remainder, etc. Then you need to go another halfway and on and on so the arrow would never reach the target because it needs to go through an infinite number of halves. There are a couple things about this that need to be addressed:

1. Of course, the arrow hits the target. So obviously there is something wrong with the logic. Too many times we think logic should drive reality. In this case, the reality trumps the logic.

2. One of the failures in the logic is that the sequence of distances can be written as ½ + ¼ + 1/8 + …. That’s because first the arrow goes through ½ the distance to the target (the first ½), then it goes through the second half (1/2 of ½ is ¼). It can be shown that the sequence adds up to one, so although it is an odd way to write 1, it is identical. (Similarly, .9999999… is another way to write 1. There was a lot of theoretical work required to handle infinities before this argument could be finalized.

3. Of course, the biggest issue in the paradox is how does the arrow get half way to the target? Why is it so special that the arrow first get halfway and then half of that, etc. We now have the paradox of how does the arrow get from where it is shot to the halfway spot. Zeno’s paradox is really about how does an arrow start moving. The answer is that the bow interacts with the archer and string to send the arrow towards the target. No paradox required!

Similarly, in the time travel paradoxes, I suggest that there are only pardoxes becuase there is no time travel so if you start your questions with, assume time travel is possible, then you can set up all sorts of non-sensical conclusions, some of whic hwill be paradoxical.

Time and Time Travel

I was going to wait a bit but this section on Time and Time Travel seems to fit very nicely right here. John Wheeler, Nobel Laureate in Physics, stated “Time is what prevents everything from happening at once.” In the previous post, we saw that the basic unit of the universe is the interaction. That would mean that Dr. Wheeler’s statement is actually backwards. The fact that things cannot happen all at once is why we have time! Let’s look at one example from the realm of nuclear physics. Assume we have two distinct protons. Since they are distinct, they are some distance from each other. (If they were in the same place, then there wouldn’t be two different particles so they would not be distinct.) . When these protons exchange a photon, that photon must pass from one particle to the other. Since photons travel at the speed of light, there is an order imparted to interactions. First these two protons exchange a photon and then after they change state they can exchange another photon with another proton. Things do not happen at the same time because an interaction requires the exchange of something and that something has a speed less than the speed of light.

So things cannot happen all at once because the only way they can change is by interaction and the unit of interaction cannot travel faster than the speed of light. There is no need for time to keep things from happening at the same time. All that is required is a speed limit on interactions. There is actually a lot more going on within these interactions but we’ll get to these later. For now, I’d like to stay with time and causality.

Einstein’s work developing the theories of relativity (special and general) showed that things that appear to happen at the same time in one frame of reference could happen at different times in another frame of reference. An example is in order here. Since he could not move at speeds near the speed of light, Einstein had to use his imagination to do “thought experiments.” In one of his most famous experiments, he imagined a train that could travel at close to the speed of light. He had one person sitting in the middle of the train and another sitting at a train station. He imagined that as the train went by the station and the person in the middle of the train car was lined up exactly with the person at the station, two lightning bolts hit the front and beck of the car at the same time (according to the person at the train station). He asked the question, “Did the person sitting in the train see the lightning bolts hit the front and back of the train at the same time?” The answer is no, since the train is traveling so fast the person in the train is a little closer to the front of the train than the back so they would see the front bolt hit first and the second bolt hit a little bit later. Einstein deduced from this that people saw time differently based on their relative speed. This was an amazing insight, since up until then everyone believed that time was the same for everyone, no matter if they were moving or standing still

Now I’m saying that the there is no time at all! But I am saying that time is a human invention, not something that is inherent in the fabric of the universe. Time is completely derived from the theory of interactions. Humans have memory and can remember the way things were before and after a number of interactions. Humans created time asa way to measure the duration of the change. This means time is related to space, which is just what Einstein thought when he created the concept of space-time. Are there any observations that support this interpretation? The answer is yes.

We discussed Feynman diagrams earlier. For simple system (like the particle diagram from last week's post) when the system goes from one state to another we see that that as going forward in time so going back to the original state would be going backward in time. But we're not seeing time going backward but just an example of a system switching between two simple states. There is no time at all, just a very simple system. We’re seeing a system switch between two or three states so over a number of interactions, each state is visited multiple times so depending on how the system transitions, we could call one way to be forward and the other backward.

Is there a direction of time? Since there is no time, there is no direction to time. What we perceive as a direction in time is an illusion. We talked about simple Feynman diagrams that can be reversed and still make sense. What about a series of events like an egg falling off of a table and breaking? The actual number of particles and interactions in just this simple series of events is staggering. It only looks simple because of the way the universe organizes itself. (We’ll talk about organization and hierarchy a little later.) If you saw a movie of an egg falling off a table shown in reverse, you would quickly discern it was nonsense. That’s because our experience tells us that systems don’t “magically” go from a disorganized state (broken egg) to a more organized state (whole egg). That is the concept of entropy, which we’ll get to a little later on.

Is there a way to explain time travel? I believe the answers come pretty clear based on last week's post. There is no way to travel into the future, because there is no future to travel to. It’s sort of like looking at a blank piece of canvas and “seeing” the finished picture. There is no picture there until the artist puts brush and paint to canvas. The future is merely the state of the universe after a number of interactions so until the interactions occur, there is really no “there” to travel to. Travel to the past is not much better. What would it mean to travel to the past? It means you would go to a state that existed previous to a number of interactions. There is no way to easily re-create the state of any system, let alone the entire universe, so although not zero, the chances of re-creating the universe in a previous state is slimmer than slim. Even worse, if you were able to re-create the state of the universe and insert yourself into that universe, you are now part of this new universe. All interactions in this universe are now different, since you were not in the original past, so the new universe would evolve in a different way. There would be no way for you to “return” to the universe you came from, since we’ve also decided there is no way to travel into the future. You would be “stuck” in this past and move into the “future” just like all the others in your “new” old universe.

Summary: There is no time travel, except in our minds.

The Nature of Change

“And these children that you spit on

As they try to change their worlds

Are immune to your consultations

They're quite aware of what they're going through

Ch-ch-ch-ch-Changes”

Changes, David Bowie

You change your mind. You change your mood. You change your clothes. But what exactly is change and why do things change? It may seem so simple because we can’t imagine a world without change. Change is the single most important thing in the universe and will strive to discuss in some detail why that would be so Since I’m trying to see if hope (which we’ll get to eventually) is part of the “fabric of the universe” we’ll need to look at some things that are not just human-based, but physics-based. We need to spend some time looking at change - how it comes about and the implications of change – so we’ll start with some basics.

It is pretty incredible how much change is part of our existence. Have you ever thought about what would happen if nothing changed? (I’m not talking about stopping time like in the Twilight Zone episode – “A Kind of a Stopwatch” - where the boorish guy had a stop watch that stopped everything around him but he was still able to move around. That was way cool, but impossible. I’m talking about NOTHING changing.) I’m not sure about you, but I can’t imagine it. If absolutely nothing changed there would be no rocks, no trees, no birds, no earth and no us – yikes! Change is so much a part of not only our reality, but it is ingrained into the very fabric of the universe. The old saying goes something like – “change is the one constant in life.” (I tried to look up this quote and found every variation of it except this one and no one to attribute it to.) Like most of these “true-isms”, it makes a lot of sense. (I was going to say it has a ring of truth to it, but I’ll have some things to say about truth later on so I’m trying to avoid that word for now.)

Did you ever stop and ask yourself why things change? (Probably not, but now that you’re here and reading this, take a moment to ask yourself - What is it about the universe that makes it change all the time and never stand still?) Is there a purpose to the changes or are they just random events. (Will I ever stop asking questions and start answering them? Yes!) I’d like to first talk about how change takes place. Examples work best here and we’ll go with three examples:

Example 1: Atomic Particles

Atomic particles interact by exchanging particles (the type of particle depends on the type of interaction). Richard Feynman came up with a diagram that allow you to visualize the interaction. (Do a web search on Feynmann Diagrams and you'll see) In this simple sort of interaction, particles (let's call them x and y) get close enough to exchange a particle and after the exchange they go off. What's interesting about these simple interactions is that they could go forward or backeards and stillmake sense. In these diagrams, time moves from left to right in this diagram but it could also move from right to left and still make perfect sense. That is not at all how things at the human level work. If you take a movie and run it backwards you know it is running backwards because things look different. There is a good reason why Feynman Diagrams can go backwards and forwards in time and still make sense, while larger “diagrams” cannot. More on that later.

In order to think about something changing, you also need to know what it changes from and what it changes into. In the world of particle physics the nucleons from above, x and y, are described by their state. Most atomic particles are described by their position (latitude, longitude and altitude – i.e., their three dimensional location), their speed and direction of their movement (together known as velocity), charge and spin. (Different particles have different characteristics, but the state of a particle is always the collection of all of their characteristics.) Some particles can be described using a half-dozen or so characteristics. Physicist’s ability to describe the interaction of only a few particles is limited. For example, we have no way to distinguish one elementary particle from another. If two protons have the same charge and spin then they are the same. They are even more identical than identical twins, since identical twins share only their DNA. Identical twins do not share mitochondrial DNA so they are still pretty different.) I sometime wonder if protons can tell each other apart. “Say, do you think Proton Betty will go with me to the Atom Smasher Ball?” Imagine how this scales up to a human who is made up of so many atomic and sub-atomic particles that there are no reasonable ways to describe the number. This complexity is a big part of how the universe works and we’ll spend some time on this concept in a little bit.

3-Way Light Switch: In an attempt to make things just a little more complicated, but more meaningful, let’s look at the system consisting of two 3-way light switches and one light bulb. A 3-way light can be controlled by wither of the two switches. In this system, each of the light switches can be up or down and the light can be on or off. Let’s say we start with the light off and both light switches down. If you move on of the switches up, the light goes on. If you then change with of the two switches, the light goes off. Let’s look at a sequence of light switch interactions and their effect on the light bulb.

Switch 1	Switch 2	Light
Down	Down	Off
Up	Down	On
Up	Up	Off
Up	Down	On
Down	Down	Off

In this example, if the switches are in the same position (both up or both down) the light is off. If they are opposite (one up and one down) then the light is on. In the example above, after 4 “interactions” the state of the system is back to where it started – both light switches down and the light off. There are also a very limited number of states and interactions that can occur. As in first example, the above sequence could go in either top to bottom or bottom to top order and it would make sense. In this small little universe of light bulb and two switches, time can go forward or backwards and still make sense. Let’s look at an example where this is not the case.

Human example of change: You’re feeling blue; you are in a “lowered mood state,” also known as depressed. You’re at home, in bed, with the lights out and soft lite-jazz playing on the radio. (My, aren’t you depressed!) It’s Friday, early evening and you had a horrific day at work. Nothing you did was right and if you had been fired it would have been better than living with your unknown job status over the entire weekend. (Will I have a job when I show up to work on Monday? What if they fire me via fax over the weekend? That would be the worst!) The phone rings and you check the caller ID and see it’s that guy/girl at work that has caught your eye. You thought about asking them out tonight, but the day went so poorly you just couldn’t get the strength to ask – the rejection would have been too much to take. You answer the phone and get asked out for dinner that night. Your mood perks right up and, “job be damned,” you’re out into the night with a smile on your face.

A lot went on to change your mood but without getting into all of the details, you had an interaction with someone and it changed you. In this case, if you played this movie backwards you would notice it made no sense. It is important to notice that simple interactive systems seem to have the ability to go forwards and backwards in time but complicated systems do not. We’ll talk some more about this in a little bit.

Looking at all of the examples, you see that every change comes about because of an interaction. An interaction can be simple, as in the first two cases or something complicated - a conversation, a text message, an e-mail or even a glance. What’s important in an interaction is something needs to be exchanged between you and the other person. (or thing – dogs make great mood changers)

So I’m saying that interactions are the only things in the universe that cause change. These interactions start from the simplest things that we know of (quarks and other sub atomic particles) and result in some of the most complex things (humans). You should be asking yourself, “How can something as complex as the Earth or humans come about from simple interactions between sub-atomic particles?” The short answer is – we have no idea. However, the facts are pretty compelling. If you have some spare time (perhaps a few months or so) take a look at Stephen Wolfram’s book, "A New Kind of Science." In it he shows how simple interactions can lead to complex behavior. His models are surprising simple and the tools to model the interactions are a PC. The results are startling and give a glimpse into how the universe has come into being.

At the atomic level, the interactions I’m talking about are the 4 (or three) basic forces of the universe – weak nuclear, strong nuclear, electromagnetic and gravity. (Both Special and General Relativity Theory describes gravity and a curvature or space, not as an actual force. Others have proposed a special particle, the graviton, which carries the gravitational force. No one has ever seen a graviton but a number of experiments agree with the hypothesis that gravity can be described as a curvature of space.) The strong nuclear force is what holds the nucleus together. Since the nucleus is composed of neutrons (no charge) and protons (positive charge) is must overcome the electromagnetic repulsion of the protons to hold everything together. It is very strong indeed but acts over a very short range (about the diameter of a nucleus of an atom.) The weak nuclear force governs radioactivity. In a weak interaction, a neutron decays into a proton (which remains in the nucleus), an electro0n (which is emitted from the nucleus) and a neutrino. This interaction allows heavy atoms to transform into lighter atoms so it is in some ways a repulsive force. The electromagnetic force can be both attractive (remember opposite charges attract) and repulsive. And then we have gravity, which leads to things getting closer together so we can look at it as an attractive force. (At very close range gravity can be repulsive. But since those conditions only occurred at the beginning of the universe and we can assume gravity works to attract things together.) So there you have it, the recipe for a universe:

0. Start with some small sub-atomic particles and add

1. The strong nuclear force to bind things into a nucleus.

2. The weak nuclear force to allow the nucleus to morph from one state to another.

3. The electromagnetic force to allow nucleus and electrons to bind together into atoms and allow atoms to bind together into molecules, which can build up into even larger groups pf molecules.

4. Gravity which has little effect at atomic scale, takes over at the macro-molecular scales to bring things together.

5. As things come together, new interactions are created and can effect the way things change. It may take a whilem but over time, you'll get everything in the universe.

If we assume the universe is built up from simple things interacting we can conclude at least two things:

1. Sequencing and Causality - Since interactions require an exchange, there is a basic causality to the universe. Things cannot “just change” for the heck of it but only when something is exchanged. The something that is exchanged is constrained to travel at less than or equal to the speed of light. Since the two interacting objects are separated by some distance (even if they are very, very close) the interactions cannot all happen at the same time. Changes occur one after the other in a serial fashion and cannot all happen simultaneously. Since change is preceded by an interaction and only after that interaction is complete can another interaction which leads to an ever more different state. Causality is a big deal, as we shall see, and appears to be integrated into the very fabric of the cosmos. Lee Smolin, physicist and author, wrote in his book “The Trouble with Physic” wrote about relativity and the notion of spacetime (Spacetime is the where you think of the universe as a four dimensional space with the three space dimensions and time as the 4^th dimension.) He says, “These days, many of us working in quantum gravity believe that causality itself is fundamental – and thus meaningful even at a level where the notion of space has disappeared.” We’ll return to this discussion a little later on, since it has a lot to do with our notion of time.

2. Non-Computability - After you go through a lot of interactions, say many hundreds of millions or billions or more, you arrive in a state that is different from where you started. In the case of a human, made up of so many atomic particles, atoms, etc. the number of interactions that go on in a second is truly mind boggling. If you look back and see how you got to your current state, you will be amazed at how your path evolved and some of the truly incredible twists and turns you went through. People sometimes misconstrue this as meaning there is some intelligent force guiding their life and interactions towards a pre-determined fate. I believe I can make the case that while there is something guiding you the path is neither pre-determined nor pre-ordained. We’ve seen that simple things (interactions which are the exchange of something) can lead to amazingly complex systems and behavior. It has been shown that these sorts of systems are non-computable. There is no way to know how the future will unfold without actually waiting for it to unfold. It isn’t a matter of not being smart enough (or omniscient enough) to “see the future” because is there is no future to see. We’ll look at this situation a little later. Obviously, people do predict the future and we can determine how some things will turn out. We need to reconcile the non-computability of the universe with our ability to do at least some prediction. We would not be able to survive very long without the ability to predict.

Summary: Change is so simple that it seems odd to even discuss it. However, I propose that although simple, change – through interactions – is the only thing that matters in the entire universe. The way things change is the same from the simplest sub-atomic particles to the most complex thing we can imagine. Change is accomplished through interactions and the type of interactions change dramatically depending on who is interacting. The interactions of sub-atomic particles are very different from human interactions, but the results is the same – change. We also discussed that because interactions cause change we can refer to these interactions as carrying a force. So we conclude that interactions carry a force which leads to changes in the things (people, particles, etc.) that are interacting. Interaction – communication - change - force all are just different ways of saying the same thing. Now you can see why actors and great communicators are so popular and powerful! We found that although simple, interactions can lead to amazingly complex systems and behaviors. But don’t be fooled, the rules behind everything are very simple. We ended with two ideas that fall out of interactions – causality and non-computability. Causality implies that things change because of an interaction and things don’t change for “no” reason. Non-computability means no one, not even an omniscience being who created the world, knows how things will turn out.