We were sitting around at the Diogenes Club last night discussing Gordon the Tramp and his astonishing time-telling abilites when I told the club that I am slowly coming to the conclusion that Time does not exist at all.
Now I know that cynics are renowned for systematically doubting pretty well most things, but even in the Diogenes Club this raised a few eyebrows.
Beachhutman, lay back in his comfy armchair and offered the observation that he felt Time was that thing that God invented to prevent everything happening all at once - and consequently Time must exist.
This is a surprisingly powerful argument for the existence of Time. If there is no such thing as Time then why hasn't everything already happend? But I was not to be put off so easily.
One of the things that makes me suspicious of time is the idea that it flows along like a river, immutable and eternal. If that is so, then how fast does it flow? Does it speed up or slow down? And can you measure the flow of time? I don't think you can.
H.G.Wells touched on this in one of his lesser known works "The New Accelerator" which involves a chemist who invents a new potion. The potion has a remarkable affect on anyone who drinks it. They find that every bodily process is speeded up a thousand fold - heartbeat, movement, thinking, everything. This enables a person to perform any task a thousand times faster than normal. However for the one drinking the magic liquid the only observable effect is that the world has slowed down to almost a stopping rate. Holding out a glass at arms length and letting it fall sees the glass seemingly suspended in mid-air. It is infact falling, but a thousand times slower than before.
This raises the question, what would happen if time did slow down? Slow down for everyone. What if the rate at which time flowed was halved or brought to one thousandth of its normal rate. The question is, would we notice it? I think the answer is that we would not. If everything was slower, including our thoughts and perceptions then it would all be seen as normal. It's just as if you record at double-speed a tape running at double-speed -it would come out normal.
That is what makes me suspicious. If we can't detect whether time is moving slower or faster, if in principle it can't be measured, then does it exist? I think not.
Beachhutman interjected with a comment, which I think he thought might bring the whole discussion to a timely close. He was, he said, reminded of something his local vicar once told him. "There are three mysteries in this world; space, time and existance - and we will never understand any of them."
Maybe he's right. Undaunted, I pressed on. "Let's take the thought-experiment a stage further - what if the rate of time flow varied continuously so that one moment it was slow the next it was fast? Could we notice that? Would it change anthing?"
Beachhutman stroked his chin thoughfully, and looked about to speak.
"There is no way," I said, "that we can determine that the length of one hour is the same as the length of another hour at another time. Nor that the length of an hour in one place is the same as the length of an hour in another place. " I got that from Poincare - so it must be right.
Kevin, the newest member of the Diogenes Club, threw into the conversation, the idea that time is irrevocably linked to relative movement. The consequence of which is that if you have a universe with only one particle, there can be no time in that universe. Now that is quite profound and took some of us no little while to get out heads around it. Of course it means that whatever Time is, it is not absolute - running on in the background without reference to anything else.
Pridian keenly observed that without time, there can of course be no time travel. The time-traveller, the morlocks, Weena - or their equivalent would have no existance outside of an H.G.Wells novel. Was I prepared to close the door on this mainspring of science fiction plots - to rule out for all time a whole genre of literature and film? Perhaps the price is too high to pay for a philosopical attitude?
Time-travel has to be a suspect kind of idea anyway, and there is one argument, a kind of modification of the Fermi Paradox, that has never been answered. Enrico Fermi, famous physicist, while sitting at lunch one day dissmissed the idea that there are aliens on other planets by the simple question, "If they exist, why has no-one seen them?" Given the extreme age of the universe and the vast number of stars, there should be plenty of them. But we see none. The same can be appled to time-travel. Given the infinite length of time before us, why do we see that no one has yet invented a time machine and travelled back to see us? The only conclusion must be that they can't. Time-travel is not possible.
But Pridian had a more sophisicated argument in favour of time to present. Quoting the time-traveller he reminded us that time is the fourth dimension. You can't have two objects occupying the same space at the same time. But they can be in the same place at different times. So time definitely exists. If you don't have a time dimension then things couldn't move and they couldn't swap places - which we know happens from time to time.
Mmmm..... This whole appeal to Special Relativity and four dimensional Minkowski space is not so clear cut it seems to me. Albert Einstein's best friend had a look at this. This is the one and only Kurt Godel, more famous for his incompletness theorems, but also a bit of a closet expert in time and space. Albert and Kurt used to take long walks around Princeton every afternoon and chat about Life, the Universe and Everything. Einstein said that the only reason he bothered turning up for work was so that he could chat with the genius Kurt Godel. And Kurt, after many walks and talks, also came to the conclusion that the flow of time is an illusion. In a short little paper he proved that if both special and general relativity are correct then our perception of time (what McTaggart called the A series) is an illusion.
"But what do you really measure when you measure Time?" I persisted. Not Time itself, that's for sure. All you measure is the passing of hands on a clock face, or the swings of a pendulum or the movement of the sun in the sky. None of these is Time. Time is an inference you draw from the movement of one thing against another. Movement is what you have. Cause and Effect is what you have. Time you have to construct from these things.
Nevertheless, I suspect that Time has more to do with the workings of the mind than the workings of the universe. The brain constructs its own timeframe to try to help sort out things into some kind of order. It is based on cause and effect. One event causes another, a moving snooker ball hits another and starts it moving. And the brain builds a framework from that, by seeing that one event causes another, it creates a framework of before and after and puts all the events it sees into the framework by inference.
I can't say that many of my fellow diogenists were convinced about the non-existant of Time. Beachhutman grunted, slid further back in his chair and said he would need some time to think about it.
The truth of this was not lost on any of us.