What is it that believes?

Draw a dot on a piece of paper. That dot is you, right here, right now.

Are you okay with that? This is the first act of imagination I am asking you to perform. There will be more, of increasing levels of outrageousness. If you find yourself struggling, the trick is to just go with it. Pretend. Like when you were a small child and the toy farm animals and train set were real animals, real trains. Of course they were not real, you knew that back then, but what if they were? What happens when the cows and sheep climb aboard the train and the train flies off into space?

Back to that dot that is you. Draw a very long line on either side of the dot. This is your timeline. To the left the line plunges back into your past, to the right it disappears into your future. A little way to the left of your dot is the day you were born, a tiny way before that the day you were conceived. The line goes an awful long way further back than that. And travel a little way along the line to your right, and soon you come to the day you die. Again, there's a whole lot more line beyond. It's a long, long line and your life is a tiny segment of it. 

While you've been doing all this (as I am sure you have been) your little dot has moved ever so slightly rightwards, towards that point on the line where you die. Like a fish on the end of a line, your death is slowly reeling you in.

You have no choice in the matter. You can't discreetly shuffle leftwards, let alone turn and run. Your belief in now, the rolling present, that means you can only move rightwards down the line is so powerful, so completely a part of what it means to be the believing you, that all you can do is meekly follow. 

Happily, we are not dots. We are three-dimensional beings in three-dimensional space, furnished with length, breadth and height. So, that dot on the line is you in three-dimensional space. Here we are free to move, back or forth, in any direction we want. Maybe I will go downstairs and make a cup of tea, maybe I will fly on an aeroplane to Japan. Whatever I choose, I freely relocate my dot to a new place in those three dimensions of space while, like a prisoner in shackles, it is dragged further rightwards along my timeline.

We can move in space with a freedom that we lack when we move in time; though in all four of these dimensions, three of space and one of time, "move" feels like the appropriate word to use.

Hang on. Lost person here. You said four dimensions. Three I can just about cope with, but that's the limit. No way is time a dimension.

It is. Here's why. 

A dimension is simply something we find useful when we are trying to describe something. In space, an obvious way to describe something is to say where it is. If you want to know where I am, one way of doing this would be to say "go two miles north, turn right and go half a mile to the east. You will reach a tower block. Go up to the 99th floor. That's where I live."

I've given you the route to my home in three dimensions: north/south, east/west, up/down. A mathematician might write this as (2, -0.5, 99) and call them my home's coordinates in space. Anywhere in space (relative to a given point) can now be represented just by changing those three numbers. (-6,000, 27, -15) means go six thousand miles due south, 27 miles west and go down 15 floors, where you will find the underground bunker where I live.

Armed with these three coordinates, you go off to find me. You get to my home, no problem. The problem is, I am not at home. If you wanted to see me you should have said what time you were coming. In other words, you should have provided a coordinate in another, fourth dimension, the dimension of time. 

Alternatively, I should have given you a fourth coordinate specifying the time that I will be (or, less usefully for you, have been) at that location. If I had given you (2, -0.5, 99, 3.15 on the 10th of October 2019) then just so long as you turn up at that location at that time you will find me.

That is an incredibly mathematical way of saying that when you make an appointment with someone you should write down both where and when it is.

So, the dimension of time is just as necessary a dimension as the three dimensions of space. All four are needed in order to pin down my whereabouts. Yet we tend not to see time as a dimension because we do not have the same freedom of movement in time as we do in those three other dimensions. We are also used to the idea that whatever time it is for me, that is the time it will be for you, ignoring international conventions. A mathematician would also point out that all four are necessary to locate me (omit one of them and you won't be able to find me) and sufficient (you could also add other dimensions which record how hungry I am, what clothes I am wearing or whether or not I am playing the piano, but none of these adds anything that helps to locate me or means that one of those original four dimensions is no longer needed).

Now, some more imagining. This time you are a woodworm deep in a vast block of wood. You can gnaw your way in any of its three dimensions, leaving a trail that twists and turns as much as you like, maybe even ties knots in itself. Now suppose one of those dimensions takes on the property of time. You can still move up and down, deeper in or further out, but you are inexorably required to move rightwards. Try as you will, you cannot move to the left. I wonder, can you still tie knots?

What a strange limitation! How could you be so blinkered?  

There is a further limitation we endure in all four of these dimensions of space and time. When we go downstairs or get on a plane, we are always moving from one location in space to one next door to it. We can't suddenly disappear from our home to reappear in Japan without passing through some or other continuous set of points in space. At the same time, our ever forward movement is from one moment to the next, never to the next but one.

And, a final constraint, maybe the most hard to reimagine of all. Wherever our body is in space and time, there too our consciousness is: that same old view with a slightly blurry nose in the bottom middle.

Could it be otherwise? Could we teleport from our homes to the other side of the world? Could we move backwards in time, or forwards into the far future? Can people really have out of body experiences where they hover over a scene and tell you what is on top of the wardrobe? Would there still be a blurry nose in the way?

Could we do any of these things by somehow reconfiguring the way we perceive space and time? 

If we could, it would be by an act of imagination, of substituting one set of beliefs for another. We would need to unbelieve that we are human beings who, by passing through a succession of moments in time have experiences, form memories and beliefs from these experiences, and instead believe that we are -- what?

What is it that would be believing then?