the grandfather paradox is a hoax

The grandfather paradox is the paradox in which you travel to the past and kill your own grandfather before he can conceive your father or mother, thereby wiping out any possibility that you would be born. It’s paradoxical because if you’re not born, how could you have time traveled to kill your grandfather (why it has to be your grandfather, not your father, I’ve never understood)?

Anyway, I don’t see why this has to be a paradox. Didn’t Back to the Future teach us that when you travel to the past and change things, you alter the timeline, effectively creating a parallel universe in which a different set of outcomes unfold? So if it’s a question of what could have caused you to be there in the past, we don’t have to look to the future at the point where you stepped into the time machine… we can just trace the causes to the point where the timeline splits and then look to the future of the original timeline at the point where you stepped into the time machine. In other words, your parents are alive and well, they just exist in a different timeline. Who says the cause of your birth, and therefore everything you do in your life, must be found in the timeline you currently find yourself in?

A more tricky scenario is one that prohibits the splitting of timelines. Let’s say that when you travel to the past, you just immediately start moving forward in time along the same timeline you’ve always been on. Regardless of what you do, you cannot split the timeline. Then a whole slew of paradoxes might ensue–not just the possibility of erasing your birth by killing your grandfather, but just the simple alteration of events as you remember them (if they no longer happen as you remember them, how did those memories get there?). To this, I say why should we assume the universe cares how things came to be? So you now have an animated lump of flesh and bone loitering around in the past without a birth to trace its origins to. As a lump of flesh and bone, it’s just there. The laws of physics don’t care about where it came from, just where it goes from here. The past is just a mental construct. So is the future. Neither exist right now. If it’s a question of tracing events to a sufficient cause, then nothing has a cause to be traced to. This is more a conceptual quandary, not a physical one. We like to picture the universe with past, present, and future somehow all clinging to existence at the same time, and so we feel there should be a cause, in the past, to explain and necessitate every event in the present. But the reality is that we project the past and the future from the conceptual recesses of our minds. The only reality is what’s going on right now, in the present, what’s just here as a brute fact. And I think that’s all that would happen if you traveled to the past and killed your grandfather. You’d just stick around because, well, you’re already here, and all the universe cares about is how the laws of nature determine the unfolding of your presence from this moment on.

You might want to bring up the concept on Minkowski space–or some similar idea that says all of time is as real as all of space. Just because the past is in the past doesn’t mean it doesn’t exist. But the catch with Minkowski space is that it’s a model of spacetime that can only be pictured in a static context–a context outside space and time–which means whatever the structure of space and time, it is fixed. It can’t change because change is a function of time, and it doesn’t exist in time, time exists in it. So if you go into a time machine and travel back to the past, you always traveled back to the past. It’s written into the structure of time. There was always someone there to say “Hey, look at the time traveler, coming from the future to visit us!” Whatever you do in the past, including traveling there, is not introduced into the past. You were always going to do it. You always did it. This means that if you were going to kill your grandfather, you always did kill your grandfather… which means you could not have been there to time travel. In other words, such a time structure is impossible. Whatever you do when you travel to the past, it isn’t killing your grandfather. Whatever you do when you travel to the past, you can’t alter the course of events.

Or maybe if you do alter the course of events, it just splits off into an alternate timeline (like the first scenario above). Maybe the structure of time is such that at any point in time, there are infinite branches, one for every possible choice a person could make (welcome to the many worlds interpretation of quantum mechanics).

But I question why any of this is needed. I question why the universe would care that you altered something in the past. I think all it would care about is the state of things in the present. If you’re present to kill your grandfather, then the universe just says “Ok, here you are; you just killed your grandfather; what’s your next move?”

Wouldn’t it follow then the equally questionable idea that everything then is determined?

An example of how you can go back in time and change things is a trite one. bit metaphysically may apply to general theory.

Let some keys be forgotten on a bench outside as you just drove away from your house and you remembered it.

If, it had not been remembered, then, the keys to the house would not be recovered , and of your kid thinking it was a sign for him to use mom’s car.
He may have driven away mistakenly , and mom could not drive to the beauty parlor .

So a while set of events could have altered a final outcome.

But the keys were remembered , and the memory, the neural transmitters worked properly -.this time.
But everything depended on going back, and it was really going back in time since the recovery of the key juxta positioned you into the original spatial arrangement.

And if the watch was forgotten as well, inside the house and was not recovered, and you were struck on the head by some falling debree after the recovery, you could not remember ever.leaving anything behind.
So as it appears, you did go back in time and changed.the course of events, and really could not find out, until recovering your senses as well.

In the macro universe the action could be similar.in establishing this ‘paradoxical’ events, unknown until a vastly longer time , or may never find out.

Is this still not paradoxical? Or am I being overly trite?

The afterthought of the point I was trying to make is, that the habitual construction of familiar space/ time arrangements becomes rote, and unthinkable, at times universal events superceed practical ones and force the eternal return to a singular and sufficient cause to action.

At times leaving behind those, events which may have covered for the disturbing and non sensible occasions to return and change the appearently sensible but destructive sources of non functional neural synapses.

I regret the failure to recognize the intended lapses, and it has brought havoc with neural transmission in part. That this is a possible paradigmn, I hope , serves as partial expiration.

Even more surreal – perhaps? – imagine this unfolding in a wholly determined universe.

Then going all the way back to what one would need to know about existence itself.

In other words, going all the way back to why something exist rather than nothing. And why this something and not another.

Or is all of existence itself just a hoax?

Actually and apparently, the paradox has been solved.
And the conclusion is as simple as suggested before.
If he goes back in time to kill his grandfather, he may not be able to, indeterminate effects, would certainly prevent the murder.
The grandfather may simply escape, or an accident may happen to the potential culprit, brought on by the increasingly transparent increasing uncertainty, which is akin to the box containing either a dead or a live cat.
The rock that hit him on his head in the process of recovering the forgotten keys, may be said to be equivocal to an apple falling into him and causing a negative effect.

The ultimate worst case possibility , that the potential killer is not hurt , or the grandpa can’t escape, is a vastly expanded simulation that presents two versions, one a simulation, the other not.

However, which is which, and at this level, the two are undifferentiable.

This is Steven Hawkins’ solution, if read correctly.

You got that right, Meno.

However, I prefer to think that whatever happens, it is determined by the laws of physics, not human logic. If you went back in time and killed your grandfather, the same thing would happen to you as would happen to any run-of-the-mill non-time-travelling killer. You would carry on as the laws of physics would prescribe.

Every time traveler knows once you step out of the present into the past or future you’re no longer affected by changes made to your past self.

This is my favorite film for exploring time travel imponderables: viewtopic.php?f=24&t=179469&p=2410742&hilit=Timecrimes#p2410742

Trailer: youtu.be/3XuWoe9NSic

There is no grandfather paradox because it stands on wrong premise that one can go back in the past causes changes there, which is immpossible. Time is liner entity which moves only in forward direction, not otherwise. Goning back into the past can happen only in reel life not real life. What has happened, has been happened and no one can change that.

with love,
sanjay