Philosophy

Different Futures

Time for you and time for me.
And time yet for a hundred indecisions,
And for a hundred visions and revisions,
Before the taking of a toast and tea...
Do I dare
Disturb the universe?
In a minute there is time
For decisions and revisions which a minute will reverse.[87]

If uncertainty means that some events have an equal chance of happening, then the story would be different if the universe was run again from the beginning with exactly the same starting conditions. Millions of different but equally likely outcomes would contribute to a different future each time.

Instead of one time line (like children draw at school) there could be lots of branches leading outwards from every point at which uncertainty is possible. This would make time more like a plane than a line. I'm sure that this is in part what Einstein objected to. Of course we only see one line in the past; only one line leads to us. But we have lots of choices from now on, only one of which we can experience.

The problem seems to be tied up with our idea of time itself. For physics to reflect what actually happens in the Universe we have found that we must incorporate time as a space-time dimension like width height and depth. Like the three spatial dimensions its meaning is defined by relationships within the Universe. There is no time without the universe; just as there was no width height or depth. And it has no meaning to ask what was 'before' the Universe.

In the world of direct experience we experience height, breadth and depth (3 physical dimensions) and time. There may be additional dimensions, more about these later, that we can infer but do not experience directly.

But time is experienced in a different way to the other perceived dimensions. We only know about time because one event seems to follow another; a second passes and that scene is now only a memory. The next second is a prediction. The present seems instantaneous. Without memory there would be no experience of time and consequently no expectation of future. But memory is an entirely biological feature of our organism. Thus our experience of time may be unique to our biology or the human brain.

Our human, common sense, concept of time may be entirely due to the way we perceive the here and now.

For example we know from repeated experiments to test relativity that an observer in a different frame of reference (travelling at a different relative speed) experiences time differently. The clocks that set GPS positioning from satellites do indeed run at a different rate according to their relative velocity.

In order to explain and predict electro-magnetism, static electric force (the force that makes your hair cling to a comb) gravity and so on, all four dimensions have to be considered as a continuum (Einstein's space-time continuum). The future and the past are as real and existent as the present.

The space-time continuum means that all four dimensions are closely bound together and all four can be stretched or bent according to relative velocity, mass (and therefore energy) defining a system. We know this is broadly true because it underlies most modern technology, allows accurate prediction of certain classes of event and if it were not at least a good approximation of reality, our technologies like GPS navigation and computers would not work.

Using the movie metaphor, the whole movie is already 'in the can'. You can start it anywhere you choose and the story will flow as it did before, as when first run; the characters having no knowledge of what will happen next. If this is so in reality you could be anywhere in the time dimension spanning your life. But it will always feel the same, as if say, you are twenty (or 30 or 60). At any point you will have identical memories of the last second and no idea what happens next.

This 'next' is defined by the state of your perceptions at that point on the time dimension.

When we dig a little deeper it becomes ever more apparent that the idea of time is moulded human perception. This instant is not infinitely short. The brain processes that give rise to our perception of the 'present' themselves take time and the 'present' is made up of a series of events that do not occur simultaneously. For example it is well known that showing a human being a series of pictures changing more often than four per second appear to us to be a continuous moving image. In other words we are unable to fully process more than four images in the second.

Other brain processes take even longer:

Brain scanner predicts your future moves[88]

• ... 14 volunteers lay in a brain scanner and were told to tap a button with a finger of the left or right hand whenever they felt the urge.
• ...When Hayne's team later analysed the fMRI scans, they found that the prefrontal cortex – a part of the brain that is involved in thought and consciousness – lit up seven seconds before the subjects pressed the button.

In other words there is around a seven second delay, like the one used by talk-back radio to allow the host to censor an unwanted remark. During this delay our unconscious brain is at work but not reporting its activities to the conscious brain. We only become aware of some decisions seven seconds after 'we' actually made them. Numerous other studies reveal similar neurological processing delays.

These studies indicate that when we want to react to something very quickly we apply a predefined set of rules. This is why we can't learn to drive a car or to ski from a book; we have to program a subconscious and nervous system so that it will react appropriately, without time consuming processing.

At the Australian Institute of Sport, elite sports players wear occlusion goggles during training, to blank out of their view of a high speed ball's flight to their bat or racquet, because this view can't be processed in time and actually confuses the brain's effective processing of the situation[89].

Each of us is an enormous corporation of cells and neurons like a giant business corporation; and as in a business the chief executive only learns of many decisions long after she is supposed to have made them. Her role like our 'conscious self' is to clean up after any mistakes and 'sell the outcomes' to the stakeholders.

So my 'now' on the timeline is a bit fuzzy. Some of my conscious 'now' and some of my 'future' are already past. As a result I have a built in perception of time and of the direction of time being driven by causality. If I stand on a pin the pain in my foot precedes my consciousness of it.

The command to get something to stop the blood was actually put into action by the troops seven seconds before the General thought of it.

This may be why time seems to fly in one direction. You have a sense of the past but less of the future. Well actually you can't see the past you can only remember the past imperfectly; again you brain is selective in what it sees and keeps. And indeed you have a fair expectation of drawing another breath, another heart beat, the world about you not suddenly disappearing and that person continuing to drone on as before.

The time dimension itself is measured out by the direction of causality. Past things result in present things and present things result in future things. One measure may be increasing entropy, the tendency to chaos, or cooling, as described by the second law of thermodynamics but this is not essential to one thing needing to happen before another can.

If this Block view of time is true then time travel is not possible as a perceived 'travel event'. We may well travel back or forward on the time dimension but no change is permitted so our perceptions are identical to those we had the first time or the six millionth time. We have no way of distinguishing one from the other; each visit is a unique point perceived, while there, as the very first.

But if different futures are possible, for example if we can change the future through the decisions we make, then time travel becomes a possibility (not a certainty), as differences (due to different choices made by billions of life forms) may well result in a Universe where this can happen.

Let's assume that Humans exist for some time into the future and continue to advance technologically so that time travel, if possible, becomes available. And let's assume the Universe is sufficiently vast in scale and duration for time travel to be developed elsewhere. This would allow space exploration across the entire universe as the speed of light ceases to be a constraint.

If this were true we should already be receiving visits from a vast array of future humans and travelling aliens.

The fact we are not is evidence that time at least up to now is 'set in concrete' - although we may be able to jump forward in future, something prevents the future interfering with the past.

This gives support to the idea that time (defined as a series of events in a specific order) is unchangeable into the future, as well as in the past.

The verifiable arrival of a time traveller would instantaneously refute the Block view of time, as being unchangeable and thus, amongst other things, affirm freewill.

It seems probable that time is a single dimension in this universe. If every one of the six billion people on the planet (and possibly animals and plants; not to mention life on other planets in the universe) is able to change the course of time simultaneously by exercising freewill, then which line do we collectively take? If different versions of each of us go in all possible directions then it may have to be in multiple universes.

When you decide to go to the pictures tomorrow night you do not annihilate all the people on the planet who have simultaneously decided to go down a different future road. But you might find that you get a better offer or the car broke down or the movie was cancelled. All decisions must somehow be taken into account in a common future (or futures).

Some people in remote countries may change the future enough for their choices to be quickly felt in Australia. But if they are living in a remote village and are not even known well in their own country, their influence may take hundreds of years to be felt here.

The problem is that they or say, some creature in another galaxy have made a decision you can't possibly know about but which will need to take yours into account if we are to go the same direction in time.

For a moment let's consider the possibility of other intelligent life. Planets have been detected around several nearby stars. It is safe to assume that there are trillions of trillions of planets like the ones in our solar system. Some, or many, of these may have life on them and sometimes this life may be intelligent.

The trillion to one chance is most of these creatures would be in other galaxies. The nearest of these is Andromeda; 2 million light years away. Most are many hundreds of millions of light years away. Even if we received a message from a creature like us in Andromeda the creature would be long since extinct before the message reached us.

Our best bet for actually meeting other life forms is on another body in our solar system or if a stray planet (without a sun; which may be in the majority) comes close some day and it happens to support life. On earth intelligence is rare (only one living species has it) so by that standard it is very unlikely that this life would be intelligent. But on balance these considerations suggest that human decisions are probably not changing cosmic futures.

Even though it seems unlikely that we are constantly going in several directions in time (but looking back see only one route to this version of you) there is a possibility that this really does happen in a limited way. Some events inside atoms may be intertwined so that decisions that change the future are instantaneously communicated throughout the universe. In this way the options for change may in some way be limited and shared by the change agents.

Some theorists now propose ten or eleven dimensions[90] (super string theory) for their calculations to explain all the various sub-atomic forces and particles and to get to a single theory explaining the laws of physics. All but four of these dimensions[91] do not seem to be evident in our physical universe. Physicists say the other dimensions are 'curled up'. Maybe one or more of these gives our universe a little extra dimension, just sufficient to stop us getting all the information from a message or knowing both the position and momentum of a particle.

In our world what looks to us like choices we make, flow out from the event like ripples on a pond to provide new options to others over time and space. So the things my father did before I was born directly resulted in my existence but things he has done since have had less and less influence on my life.

Even if there is a possibility of multiple futures, true acts of 'freewill' may still be limited to a very few events; just enough to make the future unknowable. Possibly, as some have speculated, quantum states play a part in the way that the neurons in our brains work, at a molecular level, and it is 'quantum uncertainty' that gives rise to 'freewill'. But quite clearly our brain works in similar ways to that of a chimpanzee or a dog or a spider and if this speculation is true, quantum states play a role in their brains too.

If animals have 'freewill' their indecisions too must 'Disturb the universe'. It could be that a different kind of brain to ours might see these ideas more clearly.