Why Retrocausality Can't Happen

Clock and intercom unit at my old high school in Pullman, WA.

In my opinion

What is retrocausality?

It is something being able to change the past. For instance, going back in time and shooting Aldof Hitler before he takes over Germany.

At least that's my understanding of what the term retrocausality means.

Why can't this happen?

Here are some results from the time I spend in contemplation. Yes, I get to do a lot of contemplation time working as a custodian.

Some physicists talk about the theoretical ability of going back in time. Photons being able to go back, or what ever. I guess this makes some sense in theory. In popular media, it brings up questions related to whether the past can be changed, or not.

Well, I would say that the past could not be changed, even though something might be able to travel to a past time.

The past can not be changed.

Why not?

Einstein talked about space and time being the same thing. (At least my understanding of Einstein indicates this, help me if I am off base).

He talked about "space/time."

If this is the case, then I would say that traveling through time would be similar to traveling through space. One can go forwards, backwards or even sideways through space.

As for time, our common experience always goes forward, but theoretically one should be able to go backwards as well.

When traveling backwards in space, we don't automatically expect that we will revisit the exact experiences that we encountered on our last visit to that spot space.

For instance, I recently traveled back to the space of my old high school, but I didn't expect to find my old high school experiences. I did not expect to find those same experiences just because I was revisiting that space.

The experience I did encounter was different. It was my 30th high school reunion.

My reunion wasn't being in high school again, even though I went back to the space of my old high school. No I couldn't retake a test I took back then and get a better grade.

Well, can't the same thing be said about traveling back to a place in time?

One can go back to 1973, for instance, but all the things that were located in 1973 are now "moved on." They are moved on to the present.

Going back to 1973 might not be that much different than going back to the space of my old high school. The space is still there, but the experience is different. The high school students have all moved on, gotten jobs and so forth.

When I went back, the students had all changed and the space was filled with the 30th reunion experience.

Now going back in time might bring the same idea. The year is still there, but the experience is different. Our universe is no longer residing in 1973. Going back there might mean leaving this universe. Yes there is still a 1973, but this universe has moved on. Maybe there is another universe experiencing 1973.

The space where my old grade school once stood is still there. The space is still there, but no school resides at that spot anymore.

That spot is now occupied with apartment buildings.

So, if we can go back in space and not encounter the world as it was when we visited that space last, why wouldn't that happen in time as well?

I would say that one could not go back to Germany in 1935 and shoot Hitler. Maybe one can go back to Germany and one could go back to 1935, but Hitler would no longer be there.

Maybe I am missing something? Help me out. What is wrong with this idea?

Now I know that traveling to my old high school space is not really visiting the space that my high school was in back in 1973. The galaxy is moving through the universe, so it's always in a different space. It is the same space in relation to the surface of the Earth. That is the point of reference I am using for this contemplation.

Anyway, am I missing something? Or, does this make sense? Your comments welcome.

The reason why I wrote this is because of some interesting articles that someone recently sent me about a professor Cramer, at University Of Washington. He is doing research on these issues. Check out this interesting blog article on that research.