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Informal Discussion About The B-Theory Of Time & Backwards Causation
How can effect come before cause? If it can however, it requires a different way of thinking about time as we perceive it. The future changing the past.
What if future can change past? Have you ever thought about the past and thought that it had happened differently? Maybe something you thought had happened doesn’t even exist anywhere you that discover again today. Thinking of it that way, you can never be sure what had the past really is or was. The past you know today may be altered, erased, from the past you’ll understand or realize sometime later.
Effects coming before their cause is rather interesting, as it’s debatable whether or not, by their very definition, causes must come before their effect. We always assume linear time (which seems to have a direction -namely towards the future) though some would deny time is linear. A lot of people would also deny this ‘moving now’ property, meaning that ‘The Present’ is not a special point in time; all points in time are equal (much like all spatial points). 1
Take the block model of time. Basically, time is static. There is no such thing as an absolute ‘present’. We are in a four dimensional block (composed of 3 spatial dimensions and 1 time dimension); imagine a big block of diamond that is full of little people in different poses throughout it -this is our reality. In this case, what reason would you have for denying backwards causation but affirming forwards causation? On this view, there seems to be very little basis on which to do it, save for our biased disposition. This wouldn’t involve the future changing the past, it would simply mean that one point in the block influences another; remember that no spatial points are unique or have a special ‘Now’ (or ‘Past’ or ‘Present’) property/attribute.
It should be noted that events cannot be changed. The common argument against time travel into the past is the apparent paradox of auto-infanticide. This is where one travels into their own past and kills their infant self; how can you can grow into an adult if you were killed as a baby by your future adult self? This is logically impossible and rests on a confusion between two different meanings of ‘possible’ (David Lewis pointed this out). It is possible that I could kill my infant self in that I know how to kill a human being, I’m strong enough to kill a child, etc, but is is not possible in the sense that global consistency constraints render it impossible. Any causal chain must be consistent with any causal chains to which it is attached, therefore you cannot kill yourself because you didn’t kill yourself. Failing to acknowledge this is, as one philosopher noted, akin to denying one’s car has broken down until they know the reason why it’s broken down. You will fail, because you did fail.
So, this means that the past cannot be changed like in the movies (where someone accidentally messes with the past and the future is different to what they knew). It is totally impossible. You can go back into the past (hypothetically, at least) and influence the past (an example being, say your dad told you of a mysterious stranger who saved his life before you were born, and you travel back into the past to look for this stranger. Nobody shows up and your dad is about to die and you save him -you were always the person who saved him), not change it.
1 – Actually, I think it’s worth expanding on what I was saying earlier about no points in time being unique, as in spatial dimensions. I can say ‘I am here’ and it will be true simply in virtue of where I am. If I move, I can say it again and it still being true. Similarly, a map in New Zealand saying ‘You are here’ is just as true as a map that says the same thing in England. ‘Here’ refers to different spatial points, but none of the spatial points possess any ‘Here’ property. It is simply a relative term.
This is exactly how, it is argued (and I’m inclined to agree), the term ‘Now’ works. To say ‘It is now’, or ‘I am in the present’ is exactly the same as saying ‘I am here’. They are terms relative to your points in time. Thus, no points in time have any special ‘Now’ quality (there is no such thing as an absolute ‘Present’), they are simply all points in time, not one being any different from each other.
You lost me. Surely effect cannot come before cause, if you insist that future cannot change the past. You’ve eliminated the possibility of backwards causation. You said that it was impossible to change the past.
Assuming no special bias of time, then what is the past?
Let’s deal with the first part, about changing the past. As I noted earlier, this hinges on the distinction between influencing and changing. Events influence each other, so one event can cause another. So, as an example, the event of a spark in a gas-filled room will influence the event of the house burning down. Changing an event is different, as it would involve going against what would have been. It is changing events that is impossible. An example of changing would be if I went into the past and altered what had been (say I went into the past and killed my dad before I was born) which then changes the influences between events, resulting in a different reality. It is this latter type of event that is impossible (ignoring the possibility of alternate multiple realities).
Now to address the second question. Let’s assume no special points in time. This means there is no such thing as past, present and future. You do not need these terms to talk about time, in fact they are detrimental if taken to be an absolute property of events (if one accepts McTaggart’s argument). If no point in time is special (as in, at any one point does an event have some property ‘Present/Now’) then, when we use those terms, they are simply relative to us. Someone saying ‘It is present’ 10,000 years ago is just as accurate as someone saying the same thing as I type out this response. Analogously to ‘Here’, the term ‘Present/Now’ (and so on) merely refer to events relative to an observer (you, me, the caveman thousands of years earlier than me in time).
If we eliminate the idea of a ‘Present’, or what is known as the A Theory, then we are left with the B Theory of time, which simply says that events are ordered in respect of ‘Later than’ and ‘Earlier than’, and that is all you need in order to talk about events in time. It will always be true, and has always been true, that the reign of Queen Elizabeth came earlier than the reign of Queen Elizabeth II, for example. This can never be changed, and it is all we need in order to talk about events in time.
You’ll have to explain further. How can time travel exist if things that have already happened relative to -anyone- are altered or even just influenced, yet you insist that nothing that has already happened can ever be changed? Has -everything- already happened?
You’re still running with the assumption that was has already happened (i.e. the past) is somehow different from the present or the future. There is no distinction between them. They are all just as real, all of them exist and none are in the ‘past’ while others aren’t.
I’ll try again. I insist that nothing can be changed in the way you are thinking of. We can’t change the future, we can’t change the present and we can’t change the past. Don’t try to picture yourself in time, because that keeps you thinking about the past and so on. Step outside of that and view the sum total of reality (as in, all spatial points and points of time), so you can see every event that there ever will be (some will lie in your past, some the present and others the future -relative to you, of course). Every event just is. Stick an observer in and events will seemingly be orientated towards one direction in time (what the observer will call towards the future). It will be obvious to them how events happening at their point in time will influence an event in time that happens later than that event. So, let’s say our observer fells a tree, and an event that occurs later than that event (though not by much) is the crushing of a small woodland creature. The observer will notice two events, one happening one after the other and linked in such a way that he’ll say that one event caused the other. The ‘Present’ moved from event 1 (the felling of the tree) to event 2 (the death of the small animal).
However, notice that the observer (who has the notion of the direction of time) will have no relevance to that event. The tree will be linked with the crushing of the animal regardless of whether or not the observer was there to document it in his future orientated time. The ‘Now’ property simply doesn’t exist outside of any observer.
Let’s go back to my earlier example of the person who saved his own dad before he was born. If we ‘zoom out’ (as it were) from our observation point (i.e. our location in time), we can see ALL events. Now, let’s compare this quickly to spatial dimensions. I survey my bedroom floor and see several small toys positioned at various locations around my room. If we thought about space like we do time, then if I move one toy from across the floor to another point on the floor, this would be akin to travelling in time. It simply moves from one point to another.
It is a mistake to say that all events have happened because that locates them in some other time, like some kind of meta-time. All events in time are just like all objects in space (or the toys on my bedroom floor); they are simply scattered around at various different points (though it’d be in one dimension as opposed to the 3 of space).
Let’s suppress some dimensions of space to make the analogy to time easier. Picture a platforming game. In platformers, you have (traditionally) a 2D landscape, and the main aim is to get from the left of the screen to the right. This is us on the time line. If we remove the platformer’s goal of simply moving from left to right (we remove the bias of spatial dimensions), then the platforming character would have no distinction between any platforms or baddies to the left of him or to the right of him. Spatially speaking there’d be no difference aside from the fact that, relative to the character, they either on the left or the right. Does that rule out movement, actions, causes and effects, just because we have gotten rid of that bias? Well, no. The platforms haven’t changed, neither have the baddies. What could have changed? Only the observer’s bias (in that we got rid of it). This is exactly the same with time. Cause and effect don’t break down once you remove the bias of the observer (a human observer anyway, there may be beings who can move freely in both directions in time!), the only thing that changes is the perspective of the observer. Moving from one point in time to another (time travel) is no different from moving from one spatial point to another.
How can time travel exist then? If you introduce a new person into 1970, then you have already changed something.
You’re still thinking of travelling into the past as fundamentally different from travelling into the future (which you do on your own simply by existing -or persisting through time). The person is not new to the situation; nothing has changed. That person was always at that point in time when he was that age. If all events in time are equal, his movement across time is no different from movement across space, except he has moved in a direction we are not used to. Him moving backwards in time is no different from you moving forwards in time, and I wouldn’t say you persisting through time changes anything (apart from you age, of course).
It would be bizarre if someone came up to you and said ‘How did you do that? How did you get from 10:30am to 10:31am?! That’s incredible!’. You have moved from one point in time to another. Didn’t take much effort but you did it just fine. It would be something special if we thought someone had travelled backwards but only because we are not used to that direction of travel.
– Slight re-wording of a debate I had on Darkness forums.