Shelved by: giantpenguin87 on 2012-04-12
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What makes you say the universe is infinite?
Also, if the universe is infinite then it can't expand. Something infinite doesn't have an end, but to expand it needs an end.
It's like infinity squared.
in theory, something infinite could continue to expand infinitely, such as the paradox of hilbert's hotel.
also, i don't really have a practical answer. i just thought it was a funny take on an old meme; however, yahoo answers says this:
"Infinity" is a concept designed by mathematicians to explain something that would go on literally for the rest of eternity. For example, counting. No matter what number you reach, there is always one higher, so it seems to go on for as long as you can keep counting, and beyond.
In a similar way, this is what happens to the universe. However, you must also define how the universe is expanding. In astronomy, this is based on the distance from one particle to another, both of which must be the two particles furthest away from each other. This is measured by a number, and this number is finite. As even the fastest particle in the universe has a finite speed, this means the distance it covers in a second is finite.
Therefore, no matter what the distance is between two very far particles, one second later, they are even futher apart. Like the counting, no matter which distance you get to, the particles of our universe will always travel further. Therefore, it feels infinite in concept, but all distances and speeds are finitely measured (as we can express it as a number, even if an approximate range).
What it's expanding into, though? If the universe is everything possible for our comprehension, what is further out there? It is this non-matter 'gap' that seems to go on forever, and as we cannot see it or measure it, we simply don't know. And as it has not been assigned a numerical distance or size, this 'further than the boundaries of the universe' area is assumed to be infinte to mathematicians (in concept). However, the real answer is that we don't know, cannot know, and any sizes quoted, even infinity itself, is a theoretical solution to an impossible question to answer.
As far as can be told, the size of the universe will never be infinite. It has been expanding for a finite amount of time at a finite rate, and thus its size is finite. Further, the growth will not go on forever, be it a big crunch or a big freeze. The crunch would constitute a regression, a compression, meaning the size will hit a maxima and shrink. The freeze would constitute hitting 0K, depleting the universe of energy and time itself, thus ending time altogether. At that point the universe will be at its maximum.
The questions about "what happens afterward" or "what happened before" or "what's beyond" may all be inapplicable. Reality may actually be confined to this one sample of everything. There may not exist anything outside of our universe, from beginning to end.
yes the universe is only infinite in the sense that it goes on "forever" even though "forever" is constrained to this universe. we have no true answers for what may have been before or what may come after. we cannot even be sure that the universe will continue to expand or eventually shrink. man is simply too small, too young, and too short-lived to have definitive answers.
The universe cannot be said to be infinite, even if it can be said to last "forever", where forever has some non-infinite definition.
it could be infinite since we have no proof of its origin.
So, the fact that the universe is expanding at a constant rate doesn't imply that it was smaller and more compact in the past?
possibly. let me ask you, how long must we measure universal expansion before we know that the expansion rate is constant?
How would it slow down?
who knows? my philosophical convictions prevent me from believing in absolutes, so i see no reason to believe that observation of a phenomenon accurately reflects the truth of a phenomenon.
Well, of course induction has its flaws, but you may wish to understand what the second law of motion is. If it helps, there is no friction in space.
i'm aware of said law. :( but to be completely free of any sort of friction, wouldn't one have to be in a complete vacuum? it's my understanding that space (while being mostly vacuous) contains particles of some sort that would provide minute amounts of friction. is that wrong? astrophysics is not my forte.
If you're talking about dark matter, that doesn't mean what you think it means.
i'm not talking about dark matter. at least, i don't think i am. i guess my conjecture was that outer space doesn't provide a perfect vacuum. of course, i've been wrong before.
so you agree?
"It has effectively no friction, allowing stars, planets and moons to move freely along ideal gravitational trajectories."
"But no vacuum is truly perfect, not even in interstellar space, where there are still a few hydrogen atoms per cubic meter." :D
"Effectively no friction."
But, let's go with your assumption that friction is here, so space is expanding at a constantly decelerating rate. That means it was expanding more in the past. That means that the universe was at a singularity before we currently understand it was.
probably. like you said, we are using induction to make claims about what happened in the past. but we can't be completely sure without having observed it. that's my opinion anyway.
No, this is deduction, here. Saying they'll keep moving at the same rate is induction, and I can defend induction.
nope. it's induction. induction makes claims based on probability (using particular observations to make general claims). deduction makes claims based on laws (using general principles to makes claims about particulars). i edited my original comment because what i said wasn't very clear.
No, no, you see, we observe the galaxies moving outward. That's an observation. By them moving <- we can say, from that evidence, that they must have been over -> previously. That's deduction.
you can say that, but it's still technically an assumption. you can't use deductive reasoning to make universal claims. not without allowing for a wide margin of error at least.
Why can't universal claims be made from deduction, and how are claims of the universe universal claims? You claim your own knowledge of philosophy, but I'd think you'd know the difference between the real universe and universal quantification (and thus claims).
i'm not sure how to respond. do you generally understand Aristotelian logic? to make a deductive argument about any item or group of items, you'd have to have knowledge of every instance of that item. if you apply that to time and space you begin to see how limited our knowledge is. btw, i'm not sure what point you're trying to make regarding the "real universe" and universal quantification. making any universal claim is asserting that something is true universally, absolutely, objectively, etc. everywhere for all time. it seems self-evident that man lacks the ability to make such claims. please don't call my philosophical education into question. it's all i have. :(
In order to make a deductive argument about a group of items means you must have knowledge of every instance of them. Otherwise it's induction. However, there is only one (uni) universe that we have to observe, and thus any observations we made are valid for deduction on THAT universe. Much the same if you only had one whobbergigger to observe, you cannot make a prediction of the properties of whobbergiggers, for you don't know what properties vary, but you can still make valid observations of that whobbergigger and deduce properties of it from qualities of it. This is actually one of the fundamental properties of mathematics, the ability to use previously determined properties to show other properties. And math does make universal claims of absolution with everything it does.
"it seems self-evident"
It's statements like this that cause me to doubt your philosophical credibility, because self-evidence is notably subjective, and this is your view on it (seems), so it's subjectively subjective. I don't see why man cannot learn absolutes.
math is an abstraction. and yes, you are correct when you imply that experience is subjective. to me it seems self-evident that man cannot make universal claims, but you feel differently. your reality cannot be my reality because we have different perceptions. but then again, all we have are our own perceptions.
have you heard of the paradox of epistemology? that's basically where i'm drawing my views from. and please forgive me for asserting that man cannot make absolute claims with certainty. that is just my personal belief and i should not try to apply that to everyone; however, what i was trying to get you to understand is that (in my opinion) man cannot make claims about absolutes because we have no way of knowing whether absolutes exist or not. every single thing we do, think, or observe is filtered through our unique perceptions of reality. man lacks the ability to step outside his limited perspective to see true reality (if such a thing exists). this is why i love david hume btw. i'm enjoying this discussion.
While math is an abstraction, it is also a super-universal truth. It is true within itself and apart from anything else. There is no universe in which mathematics will be different because it operates on definitions and proves itself off of its own definitions, even if those definitions (say, 1) don't properly exist in that universe.
As far as epistemology goes, you probably know of the two camps. We have the Descartes types (I forgot the name, sorry) and the empirical types. While we know that the only thing to exist is us, we get into an issue of "what does it mean to exist." For example, I know myself to exist in absolution, for I am the only thing I can confirm absolutely. But, I'm interacting with you, and you must exist to interact with me. Thus you exist.
But on to empiricism. I find the position to be somewhat flawed, because this could be a false reality. However, this being a false reality is a pointless fact, be it true. Whether this is the Matrix or the world that contains the Matrix or the world that observes the world containing the Matrix, we can still observe it and observe its patterns and describe them in theories. By continuing to describe and changing the theories to describe the information, we can come to know almost 100%. Thus is science.
Now, science is partially induction, even in their theories, but I would like to introduce you to the Law of Large Numbers. It describes that the more samples you have, the closer to the mean you'll become. In more real terms, that means the more times we observe a phenomena, the more information we have about its variance, and the better we can predict and describe it. Essentially, as the number of samples increase confirming the theory, it's less and less likely that the theory is incorrect.
Of course, I could also always use Occam's Razor to support this induction.
good thoughts. but you must agree with me that in each case you've supplied above, these are still based on assumption. from occam's razor to the very idea of numbers, we treat these ideas as fact when we actually have no standard for comparison. would numbers continue to exist in the universe if it were devoid of man? possibly, but there is no way to test it.
similarly, you say i exist because i interact with you, and you know that you exist because (to be somewhat tautological) you are self-aware. under this view (rationalism), you could accurately state that you exist, but you would want to be careful in asserting that i exist. that i interact with you is not evidence of my objective existence, it only proves that your perceive me subjectively. how would you test me to see if i objectively exist? it cannot be done; however, you are comfortable assuming that i exist. hence my assertion that all we have is our perceptions and assumptions based on those perceptions. that is the closest (in my opinion) that man can come to true knowledge. science does account for that, which i think you've acknowledged. on a side note, if you haven't read david hume, i highly recommend him. he greatly affected my worldview.
Well, if FEELS like that went on forever....
I assumed nothing to speak of my mathematics. Mathematics doesn't need numbers to exist in reality for it to exist unto itself. Much the same how I don't "assume" language, I use it. Yes, language would be nonexistent without forms to use it, but all universes in which the members wish to learn the calculations for a circle will inevitably arrive at pi.
If you remember back to Intro to Philosophy, you should've learnt about Rene Descartes and his famous "I think therefore I am." I preform actions, and I could only perform actions if I existed, therefore I exist.
Much the same I can say you exist as you perform actions and I observe them, and you must exist to perform actions.
Now I ask you, what is the difference between objective and subjective existence? Is objective existence somehow superior to subjective existence? What does it even mean to exist?
Further, Why does it matter? Let's say you don't exist objectively. Does that affect how I interact with you? No. Let's say the universe doesn't objectively exist. Does that affect the properties that can be observed of it? No.
Put simply, your views may be conceptually valid, but practically irrelevant. Like solipsism, whether it's true or not holds no bearing on the universe as it is.
And a good day to you sir! Your belief in the objective reality of mathematics, yourself, me, etc. is similar to Plato's theory of forms, which you should remember from Intro to Philosophy. He claimed that even if we didn't have the physical objects in the realm of physical existence, the idea or "form" of those objects would still exist objectively as a non-material abstraction. If that is how you choose to view objects in the universe, language, mathematics, etc. then that is just fine; however, that doesn't prove that they or the ideas of them exist objectively. It is simply not possible for us to run a test to determine that, so we can't make objective claims with full certainty. We can only try to observe and make assumptions based on available data.
Let's talk about Descartes. Your descriptions of his claims are spot on, and your reasoning that you exist because you are aware of your thoughts is perfectly in line with the views of those in the school of Rationalism. But again I say, this does not prove your objective existence. It only proves you perceive yourself. Further, there are a number of problems brought up by the claim "I think therefore I am." What is "I"? Is it your mind? Your body perhaps? And what does it mean to exist? What type of existence are we talking about? Additionally, those who subscribe to Descartes' view make the mistake of asserting that the world around them exists because they can interact with it. Yet all you can be certain of is that your mind has perceived your interaction with those objects. This doesn't mean they have an objective existence.
If you have studied beyond Rationalism and considered Empiricism, you will begin to understand where I'm coming from. David Hume took Empiricism to a logical end by asserting that the "self" or our existence could only really be described by perceptions. E.g. I perceive a bird in a tree. In what sense does this prove that the bird and tree objectively exist? To claim their existence is to assume that your perception of them is an accurate reflection of reality. Similarly, Hume said we cannot prove causation. If I notice that when I drop a Mentos into Diet Coke, it fizzes and foams, all I have watched is a succession of events. I cannot truly say that the Mentos caused the Coke to fizz because I cannot observe a true connection or cause between events, only a chronological sequence of events. But I'm going off topic.
You have asked what the difference is between objective and subjective existence. We don't know. There is no way for us to claim the objective existence of anything beyond our own perceptions; thus, if I try to describe objective existence accurately, I find myself incapable of doing so because it is beyond our abilities to do it. And even if things can objectively exist and we are accurately observing and describing them, how would we know were correct? It is untestable.
But to address your main concern more thoroughly, why does any of this matter? Is your daily life affected if nothing objectively exists? Probably not. That's completely fine. I myself live each day as if everyone I talk to is real and isn't just a perception in my brain. But that doesn't make it so. And that is my only point in all of this. Simply believing that you exist, that mathematics is a universal truth, that in all possible universes the ratio of a circle's circumference to its diameter will always be expressed as pi (and that pi in those universes will always equal 3.14159265blahblahblah), etc. does not make any of it objectively true. It may all be true, but we can't know that with certainty. So, saying that my philosophical views have "no bearing on the universe as it is" becomes a meaningless statement for both of us since what you're really saying is that my epistemological views don't fit with your metaphysical views. And that's ok. Whether or not we agree, you will likely continue to perceive your own existence and I will likely continue to perceive mine. Have a pleasant day!
maybe that may be the case, as it may constitute an infinitely unpractical statement. Maynard!
Untrue!It is virtually impossible for something to end if it's always expanding.
lolblah, and blah...blabag
i couldn't say for certain that it is infinite as such a statement would be a universal affirmative, and as such i would not be able to prove it. honestly, i just found the image humorous.