See, I can be useful. I have nothing to add to the OP, other than I don’t think my job pays me enough for my time.
Damn you Coldfire!!! you have made me look the fool…
All true, but the major significance of the equation is in the “-” sign. It’s an obvious change in the pattern, and it means that there are points (more properly called events) in space-time for which the interval is not a real number. This cannot happen when you are calculating a distance in spatial coordinates, and is a fundamental difference that occurs when you introduce a time coordinate. It’s not difficult to see that these events that are separated by an imaginary interval are so far apart in 3D space that light cannot travel from one to the other in the time by which they are separated; that is, moving from one event to the other involves faster-than-light travel.
Length, Width and Depth are the third demension. Time and space are in the fourth demension. So to say that because all 3D is able to exsist simultaniously, 4D does, too is comparing apples and oranges. They are seperate demensions.
You are confusing the space part of 4D with length, width and depth of the 3D. We are ABLE to measure LWD, we are not able to measure empty, void space. Therefore, just because we KNOW the universe has 3D, we are not able to say that all of time exsists at once.
And Coldfire does not lack tact. You are unable to read sarcasm, and that is a dangerous liability on this board.
<<Studiously ignoring all arguments>>
I remember that in one of Steven Hawking’s books - I believe A Brief History of Time, he says something to the effect that the only difference between the past and the future is which one we remember. That is, if we were experiencing time in the other direction, we would have deduced a whole new set of physical laws to explain things happening in that direction. From his point of view, there is no reason to expect one direction to be favored over the other.
Of course, he also talks about a perpendicular timeline measured in imaginary numbers, so…
JonF:
Thank you for the correction.
I was thinking of the magnitude, and carelessly forgot the mathematical distinction between the subtractend and the subtrahend, unlike the equivalence of addends.
Okay, I’ll do a term in remedial first grade.
You’re right, while (tci)^2 = -(tc)^2, it is necessary to account for the fact that t is the imaginary component on the complex plane, while spatial distances all behave as real components. My argument utterly failed to explain why there should be an implicit i in t, and not in x,y,z
[crawls back into the woodwork, muttering to himself about the negative T term in ‘associated production’, well-known particle decays where some of the products appear a tiny interval before the decays themselves.]
Coldfire (and Dayiuz):
Thanks for citing that line from CSM. When I originally read it, I thought it was ambiguous - did he mean that he had been lurking for several months, or that he had been reading the past few months posts? (I often go on extended forays into the archives when I’m trying to find an answer to a specific question – it’s addictive)
I looked at the sign-on date, number of posts, and searched his username. All suggested he was an extreme newbie.
Your interpretation is, of course, by far the more straightforward.
Hmm, there’s some merit in what Common (we’re on a first-name basis here, right?) is trying to say… For starters, time (or, to be strict about it, duration) is considered a dimension, in the same sense that length or breadth is. Also, there is no cosmological model currently well-accepted in which time does not have a beginning, although the model(s) which currently seems supported by the evidence does not have a well-defined end of time. Yes, there was once a theory (the Steady State model) in which expansion would be exponential, but all evidence runs counter to it, and no cosmologist takes it seriously anymore other than Hoyle, who proposed it in the first place.
So much for countering the quibbles made. As to the point of the OP, I think that Common is just having a very hard time articulating his ideas. If I may be permitted a restatement? (Common, correct me if this isn’t what you were saying) There’s three questions here: First, does the past, in some sense, exist? Second, does the future, in some sense, exist? Third, presuming that the answers to the first two are both yes, can the future and the past be said to exist in the same sense in which the present exists?
Does that about sum up your question, CommonSenseMan?
Yeah, there are theories about ‘ontological time’ (this is a philosophical model, not a physics-based one, which woud tend to run by what we see as the rules), that the linear way in which we perceive events is particular to our perception, but that the things that are included in time are just there (‘time’ is otherwise OUR problem). Doesn’t change how the world works for us, just a theory of what our perceptual veneer does and doesn’t include.
Perhaps our notion of a God is one that doesn’t have to perceive one thing at a time in linear order but can perceive all of the cause-effect relationships at once.
I think we cannot ask Does the past still exist ‘in some sense’? without being very clear what ‘sense’ we are considering.
For example, there is no question that the past does still exist in our memories – which is a very real existence indeed. Our memory includes our total knowledge, experience, and conceptual framework. If you saw something right now that ran counter to everything you knew (a three-eyed alien trying to sell you life insurance; God bumming quarters for a phone call; an intelligent post by me; etc.) you would be very likely to dismiss or question the evidence of the now in favor of the evidence in the past of your memory.
In fact, everything we do is based almost entirely on the past, and very little is based on the present in the sense of the here-and now moment. In a sense, the past is more real than the present because it is immutable, while the present is just a series of fleeting moments that instantly cease to exist. I think an excellent argument could be made that the past is all that is real, and the present is merely the ‘coming into reality’.
But somehow I don’t think ‘Memory’ is what CSM meant.
Indeed, the OP states that the future has already happened:
Stating that the future already exists is far more problematic. It implies a fixed, deterministic future. Sometimes people propose “changeable” futures that nonetheless somehow ‘exist’. I think we can discard this prospect as meaningless, unless we are provided with specific explanations and definitions which no one ever seems willing to supply. The essence of the ‘mutable but existent’ future theory always seems to hinge on the word “somehow”. Somehow is never an answer.
The obvious examples are big decisions that destroy a city or planet. If earth itself ‘exists’ in the future’ and then suddenly ‘doesn’t exist’ in the future, it becomes a real question what the putative original ‘future existence’ meant
However, we rarely consider how microscopic effects mold our universe. We don’t need to resort to anything as technical or theoretical as the Butterfly Effect of Chaos Theory. It seems rather clear that a slight jiggle (or any number of infinetesmal changes) during sex could cause a different sperm of the billions available to fertilize an egg (or a different sperm-egg combo may not implant at all).
Sex happens hundreds of millions of times a day (well, not to me, personally), and each act may create huge changes in the lives of countless people - the child, its family, its friends, coworkers, the people that would otherwise have had its job, seat in class, marriage partner. the effect grows exponentially with each generation of that child’s descendants. And reproduction is one tiny factor.
I introduce this non-determinist view because it helps explain why the vision of a God who sees past present and future as one isn’t instructive. If God can do this, it is because He is supernatural, not because he uses any principle that we can understand, even by analogy – any more than we can ‘study hard’ and become omniscient.
More rigorously, the implications of modern quantum physics lead to a tangle of confusion regarding the nature of cause and effect that has been called ‘the Dragon’. You have probably heard of Heisenberg’s uncertainty and “the collapse of the Schroedinger waveform”. You have probably heard of situations where observing a photon in NY could cause a change in a (quantum bound partner) electron in LA. This is very real - it’s being developed as a basis for ultra secure communications
It is tempting to dismiss such things as obscure, but you can demonstrate these effects with household items. The only thing ‘theoretical’ about them is that they contradict our intuitions. These are physical laws; they may be modified in the future, but they already describe the physical world better than the Newtonian physics most people cling to. In other words, the next revolution will be further from our intuition; it will not revert to being more Newtonian, any more than we’ll wake up to see the New York Times saying that Aristotlean physics turned out to be right after all – or evil spirits.
These principles have been tested rigorously and repeated, to high precision, by people who not only understand quantum physics, but understand Newtonian physics as well. They would pick up on any pro-Newtonian deviations very quickly. And they devote their lives to this endeavor.
That’s not an appeal to authority. They publish their results for anyone to evaluate
Let’s not forget that the Big Switch from deterministic Newtonian Physics isn’t new. The key principles date from 1880-1920 – Newton was dead when your grandpa was a boy.
So ‘seeing the future as the past’ is meaningless within any conventional sense of the terms.