"so you are at the meeting of science and the rest of the culture." JIT
and so are you, Justin. Nice to be here with you. On Aug 26, 5:53 am, Justintruth <[email protected]> wrote: > According to relativity spacetime is a continuum. A set can be be > infinite, finite and unbounded, or finite and bounded. The case of > finite and bounded is excluded for current theory, and maybe > necessarily so since the term "universe" is all inclusive so it would > include whatever was on the other side of the boundary. That leaves > the cases of infinite or finite and unbounded. > > The idea of finite and unbounded is like a basketball surface. It has > no edge even though it is not infinite like a plane. If the universe > were finite and unbounded and spherical then no matter which direction > in space you went you would end up back where we are. Something like > that may in fact be the case. > > Whether the universe is finite and unbounded or infinite is a question > the answer to which is not currently scientifically known. My > understanding is that the recent observations include a universe that > is expanding at an increasing rate. If that is true then the universe > is no longer behaving like current scientific theories predict and the > theoretical physicists have work to do. > > If you want to know what a continuum is consider this... Imagine a > point on a plane. Now imagine a small disc around that point. Now > imagine a smaller disc. For every disc size you give me, if there is a > continuum, I can find a smaller disc that is made up of points in the > continuum. So if you draw a 1 inch circle then I can draw a 1/2 inch > circle and if you draw a 1/2 circle I can draw a 1/4 inch circle etc. > If that is true for every point then the set of points is continuous. > The only problem with this idea is if there is a boundary point. If > you choose a point on the boundary you cannot draw a circle all the > way around but you could draw something like a half circle. But we are > excluding bound sets so no problem! There are better more formal > definitions on the internet in the wiki. > > Now imagine a line segment with a start and endpoint ... say the > points on a line from zero to one. Then that set has a boundary. The > points zero is one boundary and the point one is another. But if you > take the line segment from zero to one and then exclude the point zero > and the point one you now have an unbounded set! > > The numbers 1, 2, 3 etc are not a continuum because if you take the > number 2 for example and I give you the number 1 for example you can't > find a neighborhood around 2 that is closer to 2 than 1 but contains 2 > and other numbers. But fractions are a continuum because if you give > the number 2 for example and I give you the number 1 for example then > you can say "all the points from 1 and 1/2 to the 2" All those points > are closer to 2 than 1. If I give you 1 1/2 then you give me 1 3/4. > Now try to find a number that that doesn't work for.... If I give you > 1.9you give me 1.99. If I give you 1.99 you give me 1.999 etc. If I > give you 1.999999999 you give 1.9999999999! > > In fact there was some theoretical work in physics that postulated > that time and space were not continuous but were discreet or > quantized. As far as I know the work never gelled into an acceptable > theory. > > What is interesting is the relationship between time and space. > Spacetime was a 4 dimensional continuum before Einstiein. What he > found was that what is for one person two points or events imagined at > the same time but separated by a distance and that therefore determine > a length become two points that are not at the same time for the > other person and so the points no longer are a length (which is an > interval of space) but are now an interval of space and an interval of > time. So a purely spatial interval becomes a space and time interval. > So for example today now here a gun goes off and in Washington DC at > the same time a gun goes off. That now becomes today here and now a > gun goes off and then latter in Washington DC a gun goes off. > Actually, it was a man named Minkowski who sort of summarized Einstein > this way. > > It does not mean that time and space are really the same thing > however. Locally, for any given observer they are very different. > > Also, time is related to material causality, so you can have a circle > in space but not one in time. The universe may be spherical spatially > but not in time because it causes problems with causality. (However, > you can imagine a universe that repeats and in a sense that is a > circle in time! Its just that if you are to preserve causality you > describe it as a line that just repeats. How subtle the ideas of > physics!) Relativity does preserve the ability to have material > causality since no signal can go "faster than light" meaning that > nothing here can cause something over there before light could reach > it. If such an effect were discovered then the center of relativity > theory would be destroyed. It is all based on that assumption. > Therefore the future need not be determined in relativity. Causality > can exist but its effect must be local. There can be no instantaneous > action at a distance that is all. I can affect a star 4.5 light years > away from the earth relative to the earth only 4.5 years from now > relative to earth. > > (In the old theory of Newton the idea that everything was determined > was also there. But that does not mean that there is no material > cause. It just meant that if you know all of the causes and you know > where everything is and how fast it is going at one point in time then > you can predict the future forever. The same is true in relativity but > what is interesting is that it is not true in quantum mechanics. That > theory is non deterministic and only allows you to predict > probabilities. Also remember that material cause is not the cause of > the universe. It is only cause in the universe. ) > > What is interesting is that if I travel really fast it turns out that > relative to me I can get to that star in as short a time as I want. I > can get there in say 10 min and affect it - meaning cause something > there....the catch is...I must measure that 10 minutes on my wrist > watch. But someone on earth watching me would see me traveling for 4.5 > years and would watch my watch moving very slowly for those 10 > minutes! > > So the fact that it takes light 4.5 years relative to the earth to > reach some star and the fact that nothing can go faster than light > does NOT mean that I must take 4.5 years relative to my wrist watch to > get there. In fact I can get there as fast as I want! Its just that > everyone home will have aged a little more than me. > > Relativity and quantum mechanics are very interesting theories. There > are deep philosophical reasons why they seem so strange. These reasons > are because we are so confused about what "to be" means. We think it > means to be a thing in the universe but that is not really it. Numbers > are and they are not things. And even the universe is not best > described as a bunch of things. There is for example color which > exists but cannot be described just by using the idea of things moving > around in space. So you end up back in philosophy and perhaps the best > way to describe everything is that it is the experience we are having > together. Describing that experience is where science comes in. > Understanding what it means however... well... its just not > scientific.... its philosophical... and when you start to become aware > of the meaning of the universe certain experiences start to happen in > you that are not describable within the current theories. That's why > people who are only aware of science thing that the people who are not > only aware of science are such raving lunatics. > > It is also why there is interest in this group. The term "Minds eye" > is a very old term that refers to the experience of the meaning of the > universe. The interesting thing about the charter of this group is > that it purports to discuss these things rationally so you are at the > meeting of science and the rest of the culture. > > On Aug 25, 8:47 pm, Michael Berkovits <[email protected]> wrote: > > > I actually disagree with your interpretation of the continuum (though > > of course I'd be happy to hear more thoughts). This is what the link > > said: > > > "This new reality was that space and time, as physical constructs, > > have to be combined into a new mathematical/physical entity called > > 'space-time', because the equations of relativity show that both the > > space and time coordinates of any event must get mixed together by the > > mathematics, in order to accurately describe what we see. Because > > space consists of 3 dimensions, and time is 1-dimensional, space-time > > must, therefore, be a 4-dimensional object. It is believed to be a > > 'continuum' because so far as we know, there are no missing points in > > space or instants in time, and both can be subdivided without any > > apparent limit in size or duration. So, physicists now routinely > > consider our world to be embedded in this 4-dimensional Space-Time > > continuum, and all events, places, moments in history, actions and so > > on are described in terms of their location in Space-Time." > > > A continuum doesn't have to be infinite. Dictionary.com defines a > > continuum as "a continuous extent, series, or whole." It adds the > > mathematical definition of "a set of elements such that between any > > two of them there is a third element." Think of a line segment. It's > > finite, but continuous - between any two points on the line, there's > > another point. > > > When the speaker says "there are no missing points in space or > > instants in time," he is referring to the current set of space-time. > > Doesn't mean that the set can't expand. Indeed, the universe is > > expanding, thereby increasing the total amount of space in existence > > (and hence, the total amount of space-time in existence, as space is > > an aspect of space-time). > > > If you could spell out more clearly what, from science, suggests that > > the future has already happened, then I would be curious and grateful > > to > > ... > > read more » --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups ""Minds Eye"" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/minds-eye?hl=en -~----------~----~----~----~------~----~------~--~---
