The past exists in the present. Your post, made an hour ago, exists for me now as I respond. The deed you did, posting the topic, exists in the present in the form it takes on the internet. Likewise the mass murder of Jews exists in the present in the form of family lines broken or altered, cultural values strengthened and weakened, generational suffering, immigration patterns, population numbers...

If you were to go back in time, and stop the Holocaust from happening, when you came back what would you expect? If you wanted a separate reality with unseen circumstances, maybe everyone involved wouldn't be long gone, and your memory is now of a possibility and now no longer relevant in this new separate reality where everyone died is still alive and things are vastly different; if you accept a multiverse your memory, or rather the set of circumstances that lead to those events, such as we know them as our reality, was/is one such possible iteration of who knows how many, and thus your memories are still very real but not for others around you, you have perhaps created (or was already there?) the world that you now live in as this 'separate reality'.
Or, you could come back and nothing happened proving we couldn't change the present with the past and now your memory is very much still real and to those around you.
One could posit a multiverse machine or a quantum dimension jumper where one could simply jump to a world where the Holocaust doesn't happen. In this scenario too your memories would be real but not to those around you as for them in that world the Holocaust never happened.
And lastly, I think the past is very real to us. And the pasts of the other Me's in a multiverse perspective would think it was real for them too. Even, of the Me who ends up in the 'separate reality' the Holocaust would even be real to him, but not to the world he would then live in.
Idk if thats intelligible.

The past exists in the present. Your post, made an hour ago, exists for me now as I respond. The deed you did, posting the topic, exists in the present in the form it takes on the internet. Likewise the mass murder of Jews exists in the present in the form of family lines broken or altered, cultural values strengthened and weakened, generational suffering, immigration patterns, population numbers... — Noble Dust

I think that the past exists as more than just a footprint. At least I think we approach the past as if it still somewhat exists. Soldiers with PTSD are traumatized by what they saw - they re-live the moments over and over again. Their PTSD is a footprint left behind by the past - but these soldiers have PTSD precisely because they think the past is more than an unreal footprint. People can't just shrug off the past because it no longer exists. Things continue to bother people even if they're "long gone" because they think it still matters that they happened. But it can only really make sense for it to matter if the past is somehow cemented in place and really exists, and isn't just an unreal phantom, an illusion or whatever.

A world with a present identical to ours but which had no Holocaust in its past would be vastly superior to ours. It also does not make sense to say, "you murdered this person but since this person is dead and in the past, it no longer matters and you're free to go." We wouldn't be able to ascribe responsibility at all. History would literally be a lie. The present would be a foundation-less moment and nothing more.

I think that the past exists as more than just a footprint. — darthbarracuda

I'm not saying it's a footprint; it sounds like we're mostly on the same page. To expand on what I was saying, and to sort of go along with what you're saying, the past influences our current beliefs, and our beliefs determine how we perceive reality, which is to say that they determine reality. So past trauma might cause me to believe (subconsciously) that I'll never be professionally successful; the past exists not only in my present beliefs, but in my real, present circumstances, thanks to how belief mediates the past with the present. The belief maketh it so. Lemme know if that makes sense.

In the morning when I awake, I come to already understanding myself as a human, with it's own personal history/narrative, itself a small part of a wider family (I am a son, and my mother a daughter, etc), within a country, within a wider human history, within a geological timescale. History is sort of embedded within my/our experience of the world. I'm not sure it's material in the way OP is describing. As in there is a sort of 'before now timeline' existing independently, in some sort of experience-independent void, from the present that we could (hypothetically) access and alter. I think it makes more sense that conceiving history in this material sense is just part of the particular way in which humans experience and conceive of the past (as in, we just think and conceive of the past in this way, not that it actually does exist independent of these experiences in that sense). Sort of how we perceive the world around us in a naive realist fashion, but that's just the way in which our experience is structured, and not that the world around us is actually there materially and we are directly accessing this independent world. Experientially the holocaust happened in an independently existing past, but materially there's no reality somewhere that contains the facts about the past (that could hypothetically be accessed).

I'm not sure it's material in the way OP is describing. — antinatalautist

Yeah, I actually want to take it a step further and say that the past only exists in the present. I am an amalgamation of my past; my body is the food I've eaten, my beliefs are the ideas, experiences, and concepts that my mind has absorbed, my memories are an unreliable catalogue of my subjective experiences which are no longer the present. It's a view of reality that I would call generative.

No and yes:

No, I don't think going back in the past and shooting Hitler in the head would have changed much. He was a product of his time, his society and history up unto his points in time created him. The society that formed Hitler was bound in that direction, and if he were not, there would be others of his ilk. The Great Man theory is bunk.

Therefore I think it is of profound importance to ethics to maintain the reality of the past (and the future). If what happened in the past no longer "exists", then how do we distribute justice and what would be the reasoning behind it? There has to be some reality behind the past for justice to make any sense, otherwise we're starting a clean slate every passing moment.

We live in the present so yes, the past and future are reality for us. The distribution of Justice is based on societal agreement with rules, laws, customs and the rest which are formed in the continuum of the past, present & future. The past and future inexorably impinge on the present which is always becoming either past or future. We abide in the present and it is never static.

I really like what you're getting at. But could we take it even a step further and say that the past only exists in the future?

I am an amalgamation of my past; my body is the food I've eaten, my beliefs are the ideas, experiences, and concepts that my mind has absorbed, my memories are an unreliable catalogue of my subjective experiences which are no longer the present. — Noble Dust

It is true we are an amalgamation of our pasts. However when we are in the "present" we are always directed towards a future. The way I'm thinking, the present seems to be something that is never really experienced, more of a made up theoretical fiction. The objective ticking away of time is not an experience I have ever had. What I experience is constantly being directed towards the future while being informed by a past, a past that includes understandings, moods, significances, language, other people, happenings, meanings, etc. It is only upon the past that I can press into the future, but if I could no longer press into the future (if I died) then the past could not exist through me. Does this not make sense?

Regarding the darthbarracuda's original question about the holocaust, maybe what we need to do is distinguish between different senses of the past. E.g., objective past, practical past, existential past, maybe there are even more pasts... Similarly with the future.

Therefore I think it is of profound importance to ethics to maintain the reality of the past (and the future). — darthbarracuda

Darth, you should know from several episodes of Star Trek that the Time Line can not be altered. If you attempt to change the future while you are in the past, disaster will ensue.

While one can play interesting games with the past, the present, and the future, I agree that these three time zones should be taken as real, however inconvenient that might be.

Time Line can not be altered — Bitter Crank

This @TimeLine? :D We already know that!

It would become the past of the time traveller doing the changing and so it depends entirely on their person and what they believe. They wouldn't have any 'collective knowledge' to answer to.

o past trauma might cause me to believe (subconsciously) that I'll never be professionally successful; the past exists not only in my present beliefs, but in my real, present circumstances, thanks to how belief mediates the past with the present. The belief maketh it so. Lemme know if that makes sense. — Noble Dust

I'm not sure how this is different from saying the past is an "echo" or a "footprint". What I'm saying is that if the past does not actually exist then what we see as residue from the past is like a fossil of an animal that never actually existed. If the past does not exist then it no longer mattered if it happened - it doesn't even make sense to say it happened.

Sort of how we perceive the world around us in a naive realist fashion, but that's just the way in which our experience is structured, and not that the world around us is actually there materially and we are directly accessing this independent world. Experientially the holocaust happened in an independently existing past, but materially there's no reality somewhere that contains the facts about the past (that could hypothetically be accessed). — antinatalautist

So I think you get what I'm saying, but I insist that this has very problematic ethical consequences. There are people who have devoted their entire lives to making sure other people do not forget the Holocaust happened. Yet, what you are saying and what I have been suggesting is that there is no difference between a present world that "has a past" with a Holocaust and a present world that instantaneously came into existence with no past Holocaust but is in every way shape and form identical to the world that has a past with a Holocaust.

The reason we shouldn't forget the Holocaust isn't just that we don't want it to happen "again". It's that it's shameful and wrong to forget what happened. In this sense, the past is a very real thing, shrouded in darkness and inaccessible, but still very real. The inmates at Auschwitz really did get tossed into gas chambers and cremented. Their suffering is "stored somewhere in temporal memory", for lack of a better way of describing it. It's Read-Only Memory, 6 million Jews suffered and died in the concentration camps. That is a fact and it continues to be a fact even if these 6 million Jews no longer exist. Their suffering, although not in the present, is still "real".

The B-theory of time makes the most sense, ethically, since it holds that at least the past is held tight and is "real". In this way, the universe is literally "growing" 4 dimensionally. It's not just an unreal blip.

Since the obvious effect of the past on the present has been mentioned, I'll just offer the point of view that the past is potentially, e.g. if one was omniscient, knowable through the chain of cause and effect. Assuming there are no jumps in history, the chain can be followed. If there are jumps, they are either caused non-randomly (e.g. time-traveller killing Hitler, or God doing whatever) or they're somehow random.

The nonrandom causes however don't seem to put the reality of the past in danger. Time-traveller going from the present to the past and changing it perhaps can't exist after the change, thus creating a paradox (at least if we send an indefinite amount of time-travellers), unless the time-traveller moves actually in a two-dimensional time, and instead of going to the past of his present, he goes to the past of another present (to clarify this, consider a line A as the time we're living, and add a parallel B above it, C above that etc., and the time-traveller moving normally through line A, but switching to B to kill Hitler). Moreover, the time-traveller would carry his past with him, so the previous time would have to remain real (having an effect on another timeline). The other example of God surely affirms the reality of the past, as otherwise there would be no reason for his action (e.g. why, and why now?) and it would be random.

If the jump in history is random, and so some things existence does not have any reason whatsoever, it does not of course require the past in order to happen, and so, admitting this, the past may indeed be very different from what it actually was if you go back the causal chain. This type of randomness however, where nothing can be known, does not seem plausible, at least on the historical level that is as the subject here, and it's difficult to say what it could even be.

So I'd say that the past is as real as it gets through the possibility of the reconstruction of the events through a thorough knowledge of the causal chain. This potentiality is ever-present and I don't know how it could lead to two different reconstructions, unless by insufficient information, so the past would here be real as a condition of the present; and this in the case of two dimensions and a time-traveller too.

What we call the past is memory, and everyone had different memory.

There is no A series without an ego, which is why some spend so much time ridding themselves of it.

Everyone has a different point of view of shared events. That is why there are disputes in sports about who did what. Before multiple TV cameras entered the picture -- so to speak -- the only POV that mattered was the umpires's view. The number of relevant POVs is now larger. Disputed rulings can now be disputed.

The Holocaust, the launch, first voyage of, and prompt sinking of the Titanic, building St. Peter's Basilica (started in 1506), the reign of Charlemaign, the Emperor Augustus, pyramids of Egypt, and so on are events that had multiple accounts from various points of view.

Further back in time -- say the first building of Jericho (8000 years ago) -- there is on the POV of the object itself, but the object reveals facts such as it's age. Farther afield, a 10,000 year old stone skin scraper found in an archeological dig tells us this part of the world was occupied. Fossils in North Dakota tell us Tyrannosaurus rex walked the earth, there, 100 million years ago. We can reconstruct the original pangea by looking at very ancient rocks, and noting how the spreading sea floor puts distance between one place and another.

Almost all of the past is beyond everyone's memory. But that's OK because we don't base our knowledge of the past on memory.

For me, the past is real insofar as it affects the present, or can affect the future. Every one of us has been radically shaped by the events in our past, so it is real to every one of us in that sense. The past is of vital importance to working for a better future because we can learn from it. If we know that in the past X was a serial killer and we have no reason to suppose they have changed their mind, we can seek to incarcerate X to prevent them committing suture murders.

With that approach, past events that don't affect anything in the present and cannot affect anything in the future are not real. But when I combine that with my quantum-Nagarjunic-DirkGentlyish philosophy that everything is connected to everything else, I have to count every past event, however trivial, as real, because it will have affected the present and will affect the future.

But that's OK because we don't base our knowledge of the past on memory. — Bitter Crank

Then what?

To summarize the question, then:

How does presentism ground ethical claims rooted in the past (and future) if the past and future do not exist?

My question is, if the Holocaust was prevented by time traveling back to the 1920s and shooting Hitler in the head, did it really no longer happen? Did all those millions of deaths suddenly not really happen? What happened to the past when we stopped it from happening? Did it just...disappear? Or does it exist in another possible world, like an alternate reality in a multiverse or something? — darthbarracuda

I think the better question would be if the concept of time travel even makes sense. If you time travel to the past with the sole purpose to prevent a particular event, and succeed in doing so, would that stop you from time travelling back in time in the first place? Or to use a clearer example, if you go back and kill your grandfather before he fathers a child, then would that prevent you from existing to go back in time? Clearly if we look at the act of travelling back in time as affecting our own past, we run into logical problems. IMO, the only way to make sense of it all is to either make it so that time loops back in on itself (such that you wouldn't be able to prevent the particular events that led to you time travelling), or to use some form of pseudo-time travel where you travel to an alternate timeline, like in your multiverse scenario.

As for the question in the title, there are many different ideas as to what the past refers to. Eternalists view the past as currently existing in the same sense as the present in the block universe. Presentists don't think the past or the future is strictly real, but that it isn't purely fictional due to it having occurred. And finally there are those who believe that the past has no real existence at all in any sense. I suppose if you view time in the former sense then time travel will be possible, but not so much for the others.

How does presentism ground ethical claims rooted in the past (and future) if the past and future do not exist? — darthbarracuda

Shared memories, learning.

Then what? — Rich

My memory could only go back 71 years -- which is pushing it. Let's say 65 years. If memory was the only means by which I could think there was a past, It could nought go back further than 1952. How do I account for my parents? Did they spring into existence sometime in the late 1940s? More likely, they existed before I was born, and they have memories that go back to the second decade of the 20th century. At least, they reported having memories of WWII, the great depression, and so on.

This is obvious. There must be some other means to determine that a past exists:

other peoples' memories
spoken records
written records
pictures and photographs
geology - fossils, studies of rock displacement
archeology - artifacts
biology - cladistics, genomes, observation, pollen studies
telescopes
etc.

Finding clam shells in sediment at 10,000 feet in the mountains tells us that either someone went to a great deal of trouble to plant signs that the mountain had risen high above the level at which the sediments were formed, or the rock was pushed upwards.

Finding fossils in rock that is 200,000,000 years old (based on other studies) tells us that EITHER animals were alive 200 million years ago, OR that same somebody with a lot of time on his hands must have put them there--presumably to screw with our minds.

My memory could only go back 71 years -- which is pushing it. — Bitter Crank

Bits and pieces, I guess depending upon the memory of each person. Mine is pretty cloudy.

If memory was the only means by which I could think there was a past, It could nought go back further than 1952. — Bitter Crank

How else does one think?

How do I account for my parents? — Bitter Crank

From what they told you? From what others told you. From what you might have read? It all ultimately depends upon your memory.

other peoples' memories
spoken records
written records
pictures and photographs
geology - fossils, studies of rock displacement
archeology - artifacts
biology - cladistics, genomes, observation, pollen studies
telescopes
etc. — Bitter Crank

First it has to enter your memory and then you recall what you can.

All of your knowledge is what you recall from memory. How you learn varies, books, teachers, direct observation, intuition, etc. It is all gathered in memory.

You are talking about how information about anything becomes available to the mind, and you are right: memory. A very few people who have had traumatic injuries lost the ability to form permanent memories. What Henry Molaison, known by thousands of psychology students as "HM," didn't know before brain surgery, he couldn't learn later. Well, technically, he could hold names and faces together while he was with the person, but if they left the room, he forgot them, and had to be reintroduced when they came back in. He was able to manage simple way finding. He had normal intelligence and a pleasant personality. But for the most part, he lived from the age of 27 to... something like 75, without learning anything new.

However, I was nought talking about memory. I was talking about the evidence that there is a past, which is a different problem than how we acquire information and store it.

However, I was nought talking about memory. I was talking about the evidence that there is a past, which is a different problem than how we acquire information and store it. — Bitter Crank

It is the same. All evidence of the past comes from the sense if memory in flux. How we acquire it is different and how we share it is variable, but it doesn't change the fundamental flow. What is called the past is just memory and it changes all if the time. The "past" is something our minds construct along with others and it is different for everyone. Strictly speaking memory is the past flowing into present. There is no objective past.

How does presentism ground ethical claims rooted in the past (and future) if the past and future do not exist? — darthbarracuda

The past and future do not exist, but they did exist and they will exist respectively. If you believe that there are facts about what happened then I don't see why you can't base your moral judgements on that.

Our thinking on this is too far apart.

Sorry I'm confused, why do we need presentism to ground ethical claims? If presentism were true there could be no justice. It is new to me, but to me presentism sounds like the nonsense that only philosophers are capable of devising. Do we ever really experience the present? Is the present spanned? How long does the present last? When does the present become past? How can I know if I am really experiencing the present and not the past out of which I make sense of the future that I'm constantly pressing ahead into with my everyday concerns. It is possible to define the present in a non-arbitrary way so that it is distinct from the future and past? I feel like I have never once experienced this "present" that people talk of. Is it the abstract,detached ticking away of time? Because I have not experienced this, never. Is it something spiritual or mystical? I have only experienced the past and the future. Is there something wrong with me? Or is "the present" simply a case of an extremely empty and vague concept that means different things to different folks, and therefore effectively means nothing at all? The present does not exist!

By recognising the present.

We might return to your initial question about going back in time to kill Hitler. If we were to send someone back, kill Hitler and prevent him from unleashing the Holocaust, would we prevent the Holocaust?

At first glance it seems a basic causal relationship: take out Hitler (and the Nazis) and their atrocities would not be committed upon the world. We are so busy thinking about how the past made our future, we forget it events were present.

With respect to our world, no amount of time travel and killing Hitler will prevent the Holocaust. For our world, it's already been a present state and faded into the past. Creating a new timeline without Hitler and the Holocaust won't change that. If we were successful, it won't change the presence of millions who lived and died in our Holocaust.

The present cannot be negated or undone. We cannot ever alter the past or the future, only create new and/or different moments-- this mission to kill Hitler is literally pointless by these terms. It will not change anything about our past.

In this respect, concern for a present is all ethics require, for any past or future, any possible world with a (im)moral outcome, is defined in a present event. To care for any past or future, is to be concerned about a present.

The past and future do not exist, but they did exist and they will exist respectively. If you believe that there are facts about what happened then I don't see why you can't base your moral judgements on that. — Mr Bee

Yes, this is one solution I was thinking about. The past (and future) may not exist but the facts about the past (and future) exist (in some way). Therefore we can say that, what grounds historical claims are the facts about the past that transcend the material present.

I still contend, however, that the phenomenology surrounding the ethics of past events is that these past events are still "real" in some sense, and aren't only a transcendent fact. Somewhere, deep in the past, victims of the Holocaust are still "hurting". Whether this is actually true is another matter but it would seem to have some plausibility when we consider the B-theory of time, or eternalism. Facts, by themselves, do not "hurt".