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Let's say we figured out a way of traveling to the past. We make changes to the past, depending. Would those changes affect the present and the future? (it would seem so, but that seems like a hasty assumption)

The future is more complicated as we don't know what the future is, even with projections. But let's say we can travel to the future and figure out what changes we'd like to make. We go back to the present after making the changes. Would those changes affect the present and the past?

Carefully think through all the implications. What say you to this?

PhilX

If time travel were possible, you could travel into the past & kill your mother. Would you immediately disappear? But then you wouldn't have been around to travel into the past in the first place, so your mother should still be alive. And so it goes on.

Here's a good one. Say you traveled to the past and made your change. As soon as you get back, you're traveling back to the past all over again to make the change. And on and on.

PhilX

The responses to this thread merely show the impossibility of physically leaving the present. And therefore the impossibility of being able to 'go back' and change anything.

As I've stated in other threads, one can only go into the future or past 'mentally', i.e. one's awareness can go there but not the ordinary physical body. So nothing could be changed. Not to mention that Phil seems to be talking about the past and the future, as if both are a singularity. In the multiverse thread we've already discussed that there are many pasts and futures, but only the realized past and the to be realized future are what we ordinarily take as the past or the future. The rest is considered 'non-existent' even though this is only true from the point of view of our limited awareness.

Okay, so what about the idea of affecting (what appears to be) the "past" by what you can think right now? I've wondered about this many times. When I was a kid, I was in some very troubled situations. Yet somehow, I felt "connected" to something that got me through all of it. As an adult, there have been times that I've thought of sending love and courage to myself "then". Telling myself that I'd be all right. Giving the little kid some adult strength. If time isn't really linear... and maybe our existence can fold over on itself... or we're straddling multi-verses... then there's not a need to travel back or forward because we can send out ripples to all of it simultaneously... if we have the intent to do so.

I believe there may be some truth in that idea, Lacewing. Our cognition of causation in relation to chronological time is subjective and there is every reason to think that it could be much more dynamic than that in reality. For example, not only does the future depend on the present, but perhaps also the present might depend just as much on the future. We think that what we do today is what determines our future, but it might also be at least partially the case that what we do today, we do because we must do what we do tomorrow. In history, we only discuss what led to Hitler's rise and caused or 'led to' world war 2. We never consider that perhaps world war 2 had to happen, and that that was the reason that Hitler ended up rising to power and doing what he did.

Because our perception and cognition of chronological time flows from past to future we necessarily assume that the "chain of causation" flows only in the same direction. But in reality this chain might go in both directions. And what is strange is that it might make more sense to trace this "chain of causation" by going from "big" events to "small" events, rather than only considering it chronologically (as going from the past to the future).

Rederic wrote:If time travel were possible, you could travel into the past & kill your mother. Would you immediately disappear? But then you wouldn't have been around to travel into the past in the first place, so your mother should still be alive. And so it goes on.

Maybe causality itself forbids the creation of time paradoxes. Maybe it is impossible to have an effect precede its cause, which would make time travel impossible since it would violate causality. But what about parallel dimensions and "alternate" timelines?

I feel that we very often change the past to make our notions of history make us current residents feel better. Of course we don't go back physically but we can change the story and thusly our perceptions of it.

Whether our ancesters were freedom loving revolutionaries or reactionaries tearing apart civilization and the monarchies is largely a matter of perception.

Do we see the Rockefellers as liberators or enslavers Is the Biltmore estate a celebration of free enterprise or a sign of capitalistic enslavement

So, yes we do change the past, pretty much willy-nilly. It does affect our future.

I feel that we very often change the past to make our notions of history make us current residents feel better. Of course we don't go back physically but we can change the story and thusly our perceptions of it.

Yes, but that isn't enough to actually change the past. Even 1984's Ministry of Truth could not actually rewrite history to comply with Party propaganda, even though its citizens were required to accept that it could. Even with absolute control of information it's still impossible to objectively rewrite history. Who directs the shadow play inside the cave of ignorance?

Philosophy Explorer wrote:Let's say we figured out a way of traveling to the past. PhilX

What do you mean by "traveling to the past"? Such a thing is undefined.

You can't travel to the past because you don't even "travel" to the future. Think of the stasis box. Like the time machine, it's merely a science fiction concept. In which you "travel" to the future by not moving at all...

Whilst everything else does.

Leog wrote:

Philosophy Explorer wrote:Let's say we figured out a way of traveling to the past. PhilX

What do you mean by "traveling to the past"? Such a thing is undefined.

There are many terms that are undefined in science. I'm guessing that you are looking to know if it means you are physically going into the past and the answer is yes.

PhilX

Theophane said..."Yes, but that isn't enough to actually change the past. Even 1984's Ministry of Truth could not actually rewrite history to comply with Party propaganda, even though its citizens were required to accept that it could. Even with absolute control of information it's still impossible to objectively rewrite history. Who directs the shadow play inside the cave of ignorance?"

How can we know history beyond what we are taught since we were not there (unless it is recent history that we have experienced ,of course). So, we only know past history as an idea of what happened. If it has been distorted for political reasons it has been effectively changed in our consciousness of it. It is also highly dependent upon the views, biases, and choices made by the recorder of historical events. History is ultimately subjective.

Theophane said..."Yes, but that isn't enough to actually change the past. Even 1984's Ministry of Truth could not actually rewrite history to comply with Party propaganda, even though its citizens were required to accept that it could. Even with absolute control of information it's still impossible to objectively rewrite history. Who directs the shadow play inside the cave of ignorance?"

How can we know history beyond what we are taught since we were not there (unless it is recent history that we have experienced ,of course). So, we only know past history as an idea of what happened. If it has been distorted for political reasons it has been effectively changed in our consciousness of it. It is also highly dependent upon the views, biases, and choices made by the recorder of historical events. History is ultimately subjective.

I say that we should not consider physically travelling back in time because it makes no sense and is impossible. Just think about how nonsensical of a concept it is.

First of all, could you really go back into "the" past physically? Once there, it wouldn't be "the" past, would it? It would immediately be a different past, because you are there. In "the" past, you weren't there. So it would be a different past. Just thinking about it shows its impossibility.

Then, just consider the relationship between 'physicalness', 'concreteness', and the 'present' and the 'past/future'. Surely anyone can see that 'physicalness' necessarily corresponds with the present for our awareness and cognition. If it exists in the present, it has a physical existence. If it exists in the past or the future, it cannot, and never does have any physical existence. The past/future can only exist in our thoughts. If you don't believe me, look around and tell me if you can see the future or the past. Now imagine the past/future and tell me how it could ever be concrete or physical.

This is the kind of philosophical question which is only interesting to think about conceptually. Once we begin giving it any kind of real possibility it becomes nonsense and leads nowhere.