Collision with Chronos

“Huh?” Ascar’s attention jerked back into the room. He stared at Heshke with glazed eyes. “Oh. Oh, you don’t know about that, do you?”

“Don’t know about what?” asked Heshke in some exasperation.

“About what it’s like in the past. You can’t talk to the people there because they don’t hear you. They don’t see you, either. What’s more you can knock them down and they don’t react in any way at all, just lie there squirming and eventually get up again. It’s as if they were robots going through motions which time has already ordained.”

Heshke stared at him.

“Oh, I know it sounds weird,” Ascar said with a wave of his hand, “but that’s how it is.”

“Do you mean they have no consciousness?”

“They act like they have no consciousness. Like robots, predetermined mechanisms,” Ascar repeated.

“That sounds … sort of dream-like. Are you sure the Titans couldn’t be right?”

“Oh no, it accords with my theory of how the time traveller works very well. You’ve probably read fictional stories about time travel and got your ideas of time from them. They always make the past or the future sound no different in essence from present time; but we know now that they’re very different indeed.”

The physicist finished his tobacco roll and threw away the end, groping in his pocket for another. Heshke gave him one and helped him light it. “How?”

“I’ll explain. Think of the universe as a four-dimensional continuum – three dimensions of space, as is our ordinary experience, and an additional dimension which we call time, extending into the infinite past and the infinite future. If we take the moving ‘now’ out of the picture we, could just as easily call it a universe of four dimensions of space. So now we have a static four-dimensional matrix. That’s basically what the universe consists of, but there’s one other factor: the fleeting present moment, sweeping through the fourth dimension like a travelling wave.”

Heshke was no physicist but he had read widely and to some extent was already familiar with what Ascar was saying. He nodded, picturing it to himself. “The ‘now’ that we seem to be trapped in, being moved on from one moment to the next.”

“That’s right. What is this ‘now’? Does anything exist outside it? For centuries the philosophical question has been whether the past and the future have any existence, or whether only the present that we experience has existence. Well, we’ve found out the answer to that question all right: the past and the future do exist, but they have no ‘now’. In effect, they have no time. No differentiation between before and after. They’re both dead, as it were.”

“So that’s why the people in the past act like robots?”

Ascar nodded. “The travelling ‘now-wave’ has passed them by. Consciousness can only exist in the ‘now’ – somehow or other it appears to be a function of it.”

“This time-wave – what does it consist of?”

“We’re not really sure. Some form of energy that travels through the four-dimensional continuum like a shock wave. We know its velocity: it travels with the speed of light. And as it goes it has the power to make events happen and to organise matter into living forms. You know in olden times they used to talk about the ‘life force’? This is the life force.”

A thought occurred to Heshke. “You say there’s no time in the past. But what if you went back in time and changed something? What happens to the past as it was before you changed it? There’d have to be a kind of time there because there’d be a before you changed it and an after you changed it. …” He broke off in confusion.

The physicist grinned. “What you’re talking about used to be called the Regression Problem, and it exercised us too when we first realised time travel was possible. Actually, in a slightly different form, it’s an ancient philosophical riddle: how can time pass without having another ‘time’ to pass in? One instant ‘now’ is at one point and the next instant it’s at the adjacent point, passed on to the next event, and so you seem to have a ‘before’ and an ‘after’ associated with the same moment – one where ‘now’ was there and one where it wasn’t.”

“Yes, I think that’s what I mean,” Heshke said slowly.

Ascar nodded. “These paradoxes have largely disappeared now that we’re able to make on-the-spot observations. Theorists used to posit an additional fifth dimension to accommodate these changes, but we know better than that now. The universe is indifferent to all artificially imposed changes, as well as to where ‘now’ is situated. It doesn’t distinguish between one configuration and another: therefore any changes you make don’t alter anything.”

Heshke didn’t understand him. “But there’s still the old riddle, what if I went back and murdered my father before I was born …?”