# Economist: Can time go backwards?

Theory fails to forbid travelling backwards in time. But practice suggests it might just as well be forbidden. Perhaps that is for the best. If backward time travel were possible, some fool would no doubt try testing the grandfather paradox, another invention of time-travelling fiction writers. In this, a visitor to the past kills his or her grand-father before the conception of the protagonist’s own parent, meaning the protagonist could never have been born, and the murder could not have taken place.

The grandfather paradox—the observation that causality cannot work backwards—is probably crucial to an understanding of the arrow of time. It is implicit in explanations that rely on thermodynamics and the like, but has not yet been translated into a coherent mathematical theory. For the person who does translate it, however, or who otherwise solves the conundrum of time’s arrow, a Nobel prize surely beckons.

But it remains, understandably, a staple of science fiction.

## 9 Replies to “Economist: Can time go backwards?”

1. 1
ppolish says:

Can matter go backwards in time? C’mon get serious.

Can information go backwards in time? Hey, thst could help explain the Cambrian. Prophecy is information from the future right? Nostradamus baby.

2. 2
Mung says:

My money sure seems to be worth less and less over time, so I don’t see why not.

3. 3
Mapou says:

Theory fails to forbid travelling backwards in time.

This is getting tiresome. Which theory are they talking about? It’s easy to prove that time not only does not go backward but it does not go forward either. Time does not change, by definition. Why? It’s very simple. The moment one says that time can change, one must determine how fast it is moving. The speed of time would have to be given as v = dt/dt and this is nonsensical. As simple as that.

Another way of saying the same thing is: changing time is self-referential.

Time does not change, people. We live in an eternally changing present. The time that we think is changing is just an abstract time in our minds. It is because our brain is a recording mechanism and we are always located at the end of the recording. So the past seems to move away from us but it does not. The past does not exist. And neither does the future. It’s an illusion. Only the present exists.

PS. This is the reason that Einstein’s physics is self-referential nonsense, by the way.

4. 4
daveS says:

Who is in charge of measuring t? If you’re going to show relativity is incoherent, you have to follow its rules.

5. 5
Mapou says:

daveS, I’ll come back when you have something even remotely coherent to say.

6. 6
daveS says:

Heh.

Well, Einstein talks specifically about comparing the readings given by different clocks. There’s nothing nonsensical or incoherent about that. As fair as I can see, you’re just doing free-form philosophizing about “time” and saying nothing about quantities that you can actually measure with instruments.

7. 7
Mapou says:

My explanation of why time does not change is elementary stuff. I can’t add to it to make it better. If you don’t get it, that’s your problem. You don’t pay me to teach you and I really don’t care if you learn anything. See you around.

8. 8
Davem says:

The past and the future do exist.
God created Time, and has His being within and without it.
If God is limited by Time, then God is limited by something other than Himself, and would therefore not be God.

9. 9
Mapou says:

Davem, you make as much sense as daveS. Maybe you’re one and the same?