On a journey like this one, it is difficult to know where to begin, to define the singularity which is the source of this conjecture. It is really a tale of many related parts, each affecting the other, and a tale that tells itself through these other aspects of itself. So, maybe it is better to talk about these other aspects and let you decide.

**Cause & Effect**

In recent years, modern scientists have increasingly become aware of the chaos theory and its related branches; more particularly, in relation to our journey, the theories of cause and effect, and not just local causality (more on that later).

Before we get into deep physics, let’s make the assumption that some event causes another to occur, its resultant effect. For example, if I take a hammer and hit an egg, this will cause it to smash. OK, this is a very simple example, but it illustrates the point nicely. In the same way, every thought you have causes some kind of action to occur, including non-action. You would have to visualise the action of smashing the egg before you would start using the hammer to achieve the end result. This is getting a little more complex – where exactly is the defining moment that originates the ultimate cause of a smashed egg for you? Even before the visualisation, another event occurs to create the desire to follow this sequence of events, but is it this which is the defining moment, the causal singularity of the effect?

**Probability**

Now, each event which occurs is more or less likely to occur based on the previous one and its related events. In our “egg”citing example, each step along the causal event chain is dictated by probability. The desire to perform the action causes you to pick up the hammer. In other words, the desire itself causes a swing in the probability that you are more likely to pick up the hammer than not. You could just use your hand, or do nothing instead, or a million other possibilities for that matter.

Before I get too immersed in this chain of diatribe, I must clear up that **probable **and **possible **are two different things in this story. Probable means something that is “most likely” to occur. Possible is something that “may occur” but is outweighed by other, more probable options. Get the picture? Right, let’s be getting on …

The implications of this are quite mind-boggling, because if you consider the desire itself, you are lead to ask the question: “so what caused the desire in the first place; what exactly made the shift in probability from fifty/fifty (let’s assume) in favour of beating the living daylights out of the egg?”

This illustrates the complexity of the causal model, and despite the linear appearance of cause and effect, there are many related events off to the side of each prior event in the chain that exert an influence over the current event shifting its probability from probable to possible or vice versa.

**Non-locality**

And it’s not just local events either. Unfortunately, there are two camps in this argument that say that either

- The less local an event is to the one being observed, the less probable it is to have an effect on it, or
- That the distance between the two events has no impact on the probability of it affecting it.

We must always be mindful here that it is not a dipolar decision point – either it does or it does not affect it – it is a scale and the question is how much will it affect it and how significant is this effect in adjusting the probability in the causal event chain.

Now, I pulled a rabbit on you in that last paragraph – I brought into play “observation”, the bane of all experimenters, but it also emphasises the effect of cause and effect. Let us observe the classic Schrodinger’s Cat …

**Schrodinger’s Cat**

In 1935, Erwin Schrodinger, Austrian physicist and father of quantum mechanics, put forward his famous “cat paradox”. This illustrates how quantum mechanics provides no way of predicting the precise outcome of a single observation or measurement. Instead, it can tell you only the probability that the system you are studying will be in a given state when you observe it – that is, in the language of quantum mechanics, when “the wave function collapses”. Until that moment the system is described in terms of a “mixture” of all possible states.

Although quantum mechanics was developed to describe the behaviour of matter at an atomic level, Schrodinger chose to illustrate the peculiarity of the quantum description with something easier to imagine – a cat in a box, together with a radioactive atom. When the atom decays, it produces a signal in a detector that will activate a valve to release poison gas into the box. Quantum mechanics cannot tell us the precise moment at which the atom will decay, and so cannot tell us whether the cat is alive or dead at any instant. Instead, we must regard the cat as being in quantum mechanical “mixture” of both states – dead and alive!

OK, so if that is true, i.e. that the contents of the box are in stasis until the wave function collapses, what happens if we expand this postulate across space. Bring on the kittens!

**Schrodinger’s Kittens**

Let us take two kittens and put each in a sphere. Each sphere is connected to the other by a thin, long, hollow tube (smaller than each kitten). Into each sphere, we put the Geiger counter and the poison (and enough food for their long space flight to come – we’re not that heartless). Into this sealed environment exactly halfway along the interconnecting tube, we introduce a single radioactive particle as before and shortly afterwards separate the two halves of the craft by introducing a complete seal between them and set them drifting across space. Therefore, we cannot say with any certainty which half the radioactive particle is in.

At some point in the future, one of the craft lands intact on a planet and is discovered by its intelligent inhabitants. Curious to see what’s inside, they gaze through the portal we generously provided and see …

Well, as before, the kitten would be alive or dead upon observation, but the state of the kitten in the intervening journey is indeterminate and only quantified as a probability. This demonstrates the effect of non-locality at the point of observation in that the state of BOTH spheres is determined by the observation of ONE sphere providing we accept that the cat is in either one state or the other. If the inhabitant saw a living cat, then, by deduction, the other must be dead. However, this could not be proven until it too was also observed, though the original observation has already preset one probability for the other condition.

Still with me? Good.

OK, so far we have seen that things are just plain complicated out there. We have also seen that events cause other events to happen – that’s the key – and we have also seen that it’s extremely difficult to isolate the causal event for a particular effect that we have observed. In addition, until an event is observed we cannot determine its state, only its probability of occurring, and that this probability may be affected by otherwise unexpected events (non-locality).

**Time Lines**

To take another example, imagine you are playing pinball. You launch the ball up the ramp and it rolls around and drops onto a rubber stopper. It bounces off in one of a number of possible directions (since a circle is round and has an infinite number of sides, there is an infinite number of possibilities). However, the probable direction of bounce is indicated by where it strikes the stopper – on the right and it bounces right, on the left and it goes left. This can be affected by other local and non-local events, but for now, the important point is that one event can cause an infinite number of possibilities. And here’s the crunch: The final direction of travel (the **probable** direction) is determined by the product of the acting effect vectors on the event of the impact, thus reducing the possible solutions to a probable outcome occurring when it is observed.

The same is true of our perception of time. We perceive our direction of travel as straight. In other words, time is linear and we are going forward in that direction, carried forward by some momentum.

If we consider the event model we have built up in (for now) three dimensions, then your actual direction of travel from the perspective of an outside observer will be a wiggly path through the maze of events filling their perception view. Hardly straight. And I bet you didn’t know you were already a time traveller?

The hard part to get your head around is when we add non-locality so that every event in this perception field (which is infinite) has an effect on the probability of the direction of travel from the current event to the next event. In effect, all events are “in contact” causally. In addition, depending on your current event position, the likelihood of one event affecting you varies. Remember the hammer and egg? The probability of the egg smashing when you pick up the hammer is a lot less likely than when you actually hit it, but the event of “the egg” itself is unchanged until some other event causes a shift in probability in its own event bubble. Don’t forget that everything has its own event bubble and its own path.

**Time Travel**

Now that we’re all agreed that occurrence of every event (existence, past, present and future) is simply a matter of interrelated events with complex probability models, and the transition from one event to another is based on this model, the concept of time as linear and applicable to each of us equally decays and it instead becomes a device to measure our position in this event matrix.

If we measure, or record, our position in this matrix, we build up a historical record of the probabilities which have existed. Knowing his information makes it easier to manipulate causal event models and “go back” to a known point and create a new set of possibilities. Beyond our current wavefront (the probability wave we create in our current event state) it becomes harder to assess the actual outcome of events and, effectively, we exist on the boundary between classical observation and quantum realities, a very privileged position indeed. So if we choose to travel “back” in the event model (I’ll explain the quotes later unless you’ve already figured it out) it is relatively straightforward to “predict” what the consequences would be if we changed anything in that event bubble since the intervening events have been “fixed” by history.

Hang on, we said that everything was just an event and the probability of the next event coming into our observation field was a derivation of the momentum from which time is derived (to paraphrase). If everything is just an event, back and forward don’t have any true significance in this model. It’s like trying to compare apples to oranges.

The difficulty in predicting “future” ripples from a “past” event based on “historical” information is that the observational details of the event itself may differ for other observers (i.e. other events connected with it). Three blind men may all have a very different model of the same elephant they are touching, but their perspective gives them one aspect of the full probability equation. In other words, the probability effects of other events related to the “historical” event may be obscured or harder to determine as they may not be “historical” of themselves.

I’ll stop at that point or the discussion could become very long and very dry, and that’s not the point of this piece. It’s about the fact that “time travel” is probably based on this event model of existence.

If you’ve got your head around that, you’re already thinking in more than three dimensions. And I guess I’ve found the path through the story after all. You can see why I found it difficult to know where to begin since each part could have been the start, the end, or the causal singularity.