Verified answer

I'm not sure what your question is, but your logic and equation make sense.

If you think about the butterfly effect, I would agree that any change in the past will change the future. Even if you just are observing, someone could see you and in that instant of looking in your direction, their lives could be forever changed. That person's life being changed could ultimately alter the events leading up to the making of a time machine which then might never exist...

Another way to look at it is, (from back to the future) if you go back in time, that would mean there is a new timeline of "future" events which could or could not be the same as the time from which you came.

And to Jason, you can't say that changing the past event will NOT change the future.. There is no way to prove or know what would happen. Like in court, if you can't be 100% sure of something, then the fact that there is a possibility is reason enough to say that it is possible. :)

Well I am not sure I can answer your question, but what if instead of going back in time you go forward in time at an accelerated rate? Then what happens to your equation I mean Pe still leads to Tm and Pe still leads to Tt, but Pe will remain unchanged if you go forward in time, thus suggesting you can travel in time, and if you can go forward then you should be able to go backwards as well?

Anyway just a thought...

Re additional infomation...

You originally stated "Time travel isn't possible because any change in a past event means the time machine can't exist? "

Well my answer suggests that if you past event is a decision to travel to the future then it will remain unchanged after you have achieved your goal of going to the future, thus TM can exist thus Time travel can exist.

I did not believe you need to go back in time to prove time travel is possible.

Edit Part 2...

OK then what if you build your TM and go forward in time 21 years, then once there you go back 20 years. Would your Pe change then? Does that proof Time travel, or do you really want to go to a point before you build your Tm and explore the Grandfather Paradox, if so then multi universe theory would be the only way Time Travel would be possible. As (As I am sure you know) killing your grandfather before he concived your father is impossible, and that would imply that Free will does not exist hence everything we have done or will do is already set and we have no power to change it. (But again I am sure you already know this, so I am sorry for typing it, if it is not what you are looking for)

No it doesn't show what you are saying.

Of the many reasons, here is one:

You wrote:

C(Pe) = -Pe

... but here, Pe *does not need to be identical* with the previous Pe. That is, your time machine was the result of a past event, but even if you go back and change a past event, the event you change does not have to be the one which caused the time machine to exist.

If Pe stood for *all* past events, there might be more truth in what you wrote. But then you would have to prove that changing a past event changes all past events, and there's no proof of that here.

If you *did* indeed go back and stop yourself inventing the time machine, you have a nice time paradox there.

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EDIT REPLYING TO QUESTIONER'S COMMENT:

You say: "Pe means Past event, But a specific past event."

If so, like I say, you haven't proven your point.

Take two past events - call them Pe1 and Pe2. Pe1 led to the creation of the time machine, but Pe2 had nothing to do with whether the time machine was created or not.

If you went back in time and performed:

C(Pe1) = -Pe1

... your time machine no longer necessarily exists.

But if you performed:

C(Pe2) = -Pe2

... it still does exist.

Therefore, it is not *necessarily* true that your time machine becomes impossible due to a change in past events. You could change past events that have nothing to do with your time machine's existence.

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FURTHER EDIT:

If Pe -> Tm means that Pe is the *necessary* reason for Tm, then of course, if you remove Pe, you remove Tm. This is a classic time paradox (see Heinlein, 'by his bootstraps') which is why I said before:

"If you *did* indeed go back and stop yourself inventing the time machine, you have a nice time paradox there."

And replying to Penelope: I didn't say -Pe2 wouldn't affect the future. I said it wouldn't affect the future of the time machine specifically - in other words, that the futures it changed didn't include Tm.

The alternative is to say that *every single* past event would make a time machine impossible if changed.

Enough edits already lol!

Look at Hoare logic

http://en.wikipedia.org/wiki/Hoare_logic

This is very much just a taster, you will need to do a LOT more reading and I'm not too sure if it is even applicable. But basically, you're trying to simplify things by doing a proof system. The only way that simplifies things is by making it easier for really smart people to agree with you. However, you need to know how to properly write proofs first. However, I don't see why you can't formally and logically argue your case.

You have forgotten to account for the possibility that the Time machine was the reason for the Past event that leads to Time travel and change then becomes a constant, i.e. there is no real change it is only a perceived change by the time traveler:

Tm --> Pe

Pe -- > Tt

Therefore:

Tm --> Tt

Pe --> Tm

this is the paradox that people explain in the movies with time machines in them. that is why they cant be seen by anyone, or else it will result in a change of a past event. this is not the only theory there is to say that time travel cant exist...for example, the same matter cannot occupy the same plane of existence at the same time. there are many things to say that time travel is possible, and this paradox is a well-known supporter of that side. :)

But past event remains unchanged unless it is a total life change....can you be a different person than you?....can you undo what you did yesterday?....past event is within you, no space out side you for it,

you may talk about objects outside you...you no longer know them unless told or written...to read you should know how to read

So your assumption past event change as far me is concerned is false unless it is a complete change in what we call "life"....and no time travel as such....rather time travel is a relative change in physical change in living beings and objects

Keep on thinking in this manner.

It's healthy for the brain!

Time Travel is at best IMPRACTICAL - according to Einstein's universal theory which equates ENERGY MASS and the SPEED OF LIGHT. There is a (Little known) Extra term called BETA... which cancels to 1 - when you're in an INERTIAL REFERENCE FRAME.

Thus it's seldom talked about.

Read Einstein's papers... no reason to re-invent the wheel

Do you know why we can time travel?

It's because we are an insane, dumb, counterproductive bunch of parasites that can only judge speed from one object to another. We are products that don't exist. We create our own worlds and constantly try to justify our actions because the truth of the matter is that we never face the truth.

How can you get to a place before it happened in this case?

The case of so called human beings.

Do you know what parallel universe is?

No need to write these seemingly complicated "equations". You wil find more answers if you grab some random science magazine.

You are missing a very important premise.