The Playground of Consciousness

Part 1: Experiments and Experience

Science

“It does not do harm to the mystery to know a little about it. Far more marvelous is the truth than any artists of the past imagined!”
– Richard P. Feynman

The mystery of quantum physics
Changing the past from the present
Summary: t he cosmology of physics

The area of the playground of consciousness that we are most familiar with is what we call “the physical universe.” It is only natural, then, that we take this as the first step in our discussion.

Note: This paper isn’t meant to be a complete introduction to quantum physics or psychic phenomena. Please see the links below for a more in-depth discussion of some of the principles.

Don’t worry if what you read here is confusing or incomprehensible. Quantum behavior is unlike anything you know about. Because this behavior is so unusual and unlike anything we know, it’s very difficult to get used to, and it appears confusing and mysterious to everyone, even to experienced physicists. Many physicists and Nobel Laureates, including Richard Feynman who I quoted above, admit they do not thoroughly understand what is going on.

If you don’t want to work through all the details, you can go straight to the summary.

The Mystery of Quantum physics

In the early part of this century, scientists accumulated more and more evidence of strange behavior of the building blocks of matter they were investigating.

Waves as particles

Light had always thought of as waves. But a phenomenon called the photoelectric effect was puzzling them. When a beam of light is shone on a metal plate, electrons are released, which in turn.produces an electric current.

In the classical picture, one would expect that the electrons accumulate energy from the incoming light, and are released when they reach a threshold. This is somewhat like the energy a rocket needs to leave the Earth. The chemical energy of the fuel is transformed into kinetic energy of the rocket. When the rocket is flying fast enough, it can leave the gravitational pull of the earth.

But this is not what happened. No electrons were emitted when the frequency of the light was below a certain minimum frequency. The explanation Einstein came up with is that the electrons can only take up energy in packets or ‘quanta’ of energy. If the energy in the packet (related to the frequency) is not sufficient, the electron sends the packet on its way again. If the energy is sufficient, the electron is ejected.

Apparently, light, which had always been thought of as waves, sometimes behaved as particles.

Particles as waves

Perhaps even stranger is that the reverse is also true. Objects that we think of as particles, sometimes behave as waves.

When you throw a stone in a pond, it will generate a circular wave that moves outward from where the stone hit the water. When the wave reaches a small opening in a wall, it will once again behave as a ‘point source’, and start a circular wave from that point onwards. This effect is called diffraction.

You can see this for yourself when you look through the narrow opening between two fingers. As you move them closer together, the edges become blurry because the light is diffracted more and more strongly around the edges. This is also an illustration of the wave behavior of light.

The remarkable finding is that the same thing happens for particles like electrons, and even for billiard balls! The more energetic or the heavier the particle, the weaker the effect. This means that for an object we can actually see, the effect is too small to be observed.

Probability waves

We are left with a confusing position: what we think of as particles sometimes act like waves, and what we think of as waves sometimes act like particles. Erwin Schroedinger found the equation that determines the evolution of these quantum waves, but it was unclear what it actually meant. Then, Max Born proposed in 1926 that the waves are, in fact, probability waves. The strength of the quantum wave at any point indicates how likely it is that the quantum particle is located there. We can observe a quantum of light or an electron when it makes a mark on a screen.

The single mystery

When you throw two stones in a pond at the same time, right next to each other, the two waves they produce will interfere. In some places, the waves will reinforce each other; in others they will cancel out.

The same thing happens when you send laser light through two narrow slits onto a screen. Where the waves reinforce each other, the image on the screen will be bright, where the waves cancel out, the screen will be dark, with varying degrees of brightness in between. This pattern is called an interference pattern.

The story doesn’t end there, however. Quantum physics wouldn’t be considered so strange if some weird effects did not occur. When you close off one of the slits, the interference pattern disappears: there is - after all - only one wave.

Light behaves as a particle when it hits the screen and leaves a bright mark there. Now, since light can also behave as particles, we should be able to measure through which of the two slits the light particle or photon travels on its way to the screen. When you put a device at one of the slits that gives a signal when a photon passes through it, we encounter the first mystery of quantum physics: the interference pattern disappears! Apparently, light can’t act as a particle and as a wave at the same time.

Or can it? Say we want to see how one single light quantum or photon behaves. We send the photons through the slits one at a time, leaving both slits open, and not measuring through which one the photon travels. Amazingly, after a while, we still see the same interference pattern appearing! If we look which slit the photons pass through, the interference pattern disappears once again. It looks like the one particle is traveling through both slits at the same time!

Parallel universes

In his book, The Fabric of Reality, dr. David Deutsch puts forward a convincing argument that the deflection of the light is caused by particles we cannot see. We can’t see those particles because they live in parallel universes. The single photon moving through the slits is pushed around by its neighbors in nearby universes, and it helps push around its own neighbors. When it seems the photon is moving through both slits at the same time, what is happening is that the photon is moving through one of the two in our universe, and some counterparts are moving through the other in their universe.

This isn’t just true for light. All particles behave like waves. In other words, for every possible situation, there is a universe or world where that possibility is ‘actualized’. This point of view has come to be known as the ‘many-worlds’ interpretation of quantum mechanics.

Schroedinger’s Cat

To illustrate this further, Schroedinger came up with a thought experiment involving his cat. He set up an experiment in which a geiger counter (measuring radioactive decay) has exactly a 50% chance of firing. If it fires, then poison is released, which his cat will then drink with rather unfortunate consequences.

The important thing is that all this happens in a box. We can’t see what is going on inside the box. As long as we haven’t looked in the box, it is equally likely that the cat is dead or alive. With our knowledge, we can’t distinguish between the two universes: one where the cat is dead, the other where it is alive. It is only when we look that one or the other is chosen.

Heisenberg’s Uncertainty Principle

We also see that the mere act of observing has an effect. We saw earlier that when we look through which of the two slits the particle passes, we get a different result from when we don’t look.

The reason is found in the famous Heisenberg Uncertainty Principle. It is easily derived from the mathematical equations. In its most common form, it says that there is a limit to how precise we can measure the position and the momentum (mass times velocity) of a particle at the same time. There is an inherent uncertainty in Nature about “what will happen next,” and in the 3/4 century since the discovery of this principle by Heisenberg, all efforts to get around this uncertainty have failed.

So it isn’t simply that our measurement changes the particle in some way. It is our knowledge of the world that determines what can happen. Apparently, Nature only allows us to know so much about itself. By deciding what we want to know, we as observers have a central role in determining the world’s future.

Changing the past from the present

In the previous section, we saw how the choice of what one wants to measure in an experiment plays a central role in determining what happens. With a variation of the two-slit experiment, we can go even further, and show that a decision in the present can change or determine what happened in the past. The setup of this “delayed choice” experiment is depicted in figure 2 below:

The setup of the delayed choice experiment.
Figure 2: Setup of the delayed choice experiment

The laser fires photons at a semi-penetrating mirror. Half the light goes through, half is reflected. The light beam is split in much the same way as it would be when it had to go through the two slits at the same time in the previous experiment. Again, because of the slightly different distances traveled, we get an interference pattern at the detector. The pattern remains when we send one photon at a time. The mirrors play the role of the slits. Removing a mirror is equivalent to closing a slit: the interference pattern disappears. When we put a detector at position X to see which of the two paths a particle takes, the interference pattern also disappears.

We come to the essence of this experiment when we put a device at position X that only decides at the last moment whether it will measure the passing of a particle. This choice has to be made so fast that the light must have already passed the half-penetrating mirror, and so part of the light wave is already underway in the other direction as well.

So what happens? As expected, the interference pattern disappears. This means, however, that the light wave that was already underway in the other direction must have been stopped in its tracks. In other words: the past has been changed by a decision in the present .

Summary: The cosmology of physics

What do these experiments tell us about the nature of physical reality? We see a universe with an inherent uncertainty about what will happen next. Every one of these possibilities is real and is explored. Moreover, this exploration starts from the Now point of the observer. All places and times exist at once. We experience reality as the flashlight of our consciousness points in different directions. As one of the founders of quantum mechanics, Erwin Schr'dinger, put it:

"For eternally and always there is only now, one and the same now; the present is the only thing that has no end."

It follows that our experience in the physical world is not primarily the result of our interaction with some ‘world machine’. Rather, it is directed by our own choices. As another pioneer, Niels Bohr, said:

"Causality may be considered as a mode of perception by which we reduce our sense impressions to order."

The observer plays the central role in determining what happens. In the remainder of this paper, we will turn our attention to consciousness to learn more about how it interacts with the physical world.

Resources

These sites may give you further information about the material in this paper.

A brief tutorial explaining the most important effects in quantum physics can be found at the web site of Science & Spirit magazine.
The University for Colorado has an excellent collection of online demonstrations, including more on waves on its Physics 2000 site. You can find out more about some of the experiments we talked about there in their “Atomic Lab” </p>
Another interactive demonstration of the interference effect can be found here.
For a wealth of links about all disciplines of physics, including some online tutorials, visit PhysLink.
Another general site is the PhysicsWeb.