• Gregory
    4.3k
    So I was considering how an infinite past is not a true infinity because time constantly disappears and all that exists are motions in the present. However, how does the concept of block universe come into the picture here. Would we have an infinite sphere (like that of Parmenides) wherein we live and subjectively experience time or is there another way of seeing this? Thanks
  • jgill
    2.4k
    It's unfortunate the word "block" is used in this regard. It immediately configures the mind in a certain way that might be hard to ignore when contemplating time.
  • Gregory
    4.3k
    It's unfortunate the word "block" is used in this regard. It immediately configures the mind in a certain way that might be hard to ignore when contemplating time.jgill

    Is time more often than not misunderstood?
  • aRealidealist
    130
    Understanding this word, "in-finite," in the most literal sense, which is strictly negatively, or, in other words, as in meaning not-finite or not-limited, then an "infinite shape," such as either a block or sphere, would be/is a contradiction in terms. For, for a shape to be one necessitates that it has extremities/edges or is bounded; & as being bounded means the same thing as being limited, then, by definition, what has extremities/edges or is bounded, i.e., a shape, can't be not-limited or unlimited, insofar as this amounts to saying that what's bounded isn't bounded (self-contradiction). Thus an "infinite shape" is a contradiction in terms.
  • Gregory
    4.3k


    I'm not sure you are right. There are different types of infinities so an object might be infinite in some ways but not in others. I hear many physicists say that the universe can be infinite and bounded at the same time. There is Gabriel's Horn as well (something finite with an infinite surface area)

    My personal opinion is that "A Time" is correct and that the past is not infinite because time is always slipping away. Talking about objective experience is hard because of all the ways we take up reality, construe, and interpret it. In a sense we feel, when we are honest with ourselves, that we construct the world. Experience is not "meant" on it own because it's hard to conceive what is purely given to us. We make our own self consciousness and choose ways of saying the world.

    However, if time is objectively an eternal instant and infinite motions hold together frozen in that instant, it seems to me the series would be geometrically infinite. How to understand the infinite is hard nonetheless
  • Pfhorrest
    4.6k
    Think about space for comparison. There isn't a place that is the first place, with a second place next to that, and a third place further in the same direction as that, and so on. We can assign numbers to places as a coordinate system, but that's just us making a map of the underlying space, and when we do that, of course we're inclined to put "zero" somewhere significant to us. If space is infinite, that just means that for each place next* to us, there is another place next to that in the same direction, and so on, without there ever being a place beyond which there is no other place. No matter which direction we're talking about.

    Likewise with time. There's this moment, and a moment after it, and a moment before it, and each of those has a moment further in the same direction, whether future or past. There's nothing special about the fact that we're counting up from zero in one direction and down from zero in the other direction; the numbers are just ones we're arbitrarily assigning to them, we picked an arbitrary time to call "zero" and count forward and backward from there. If time is infinite, that just means that for every moment in the future, there's another moment in the future of that; and for every moment in the past, there's another moment in the past of that.

    So worrying about metaphysical problems with an infinite past is basically the same thing as worrying about whether there's a most-negative number. Whether a point in time is labeled with a positive or negative number is completely arbitrary. If you have no problem with there always being a place further in the same direction as another place, or a time after any other time, there should be no problem with there always being a time before any other time.

    Or course it's still possible, maybe, for there to be an end to any of those series. It's just not metaphysically necessary for any "woo infinity is scary" reasons.


    *Yes, I know; all of this "next" talk is glossing over the issue of continuity, and speaking as though space and time is discrete, just for ease of discourse. If you don't know what I mean in this aside, just ignore it, this is just for the math pedants.
  • aRealidealist
    130
    Apologies for the late reply.

    I'm not sure you are right. There are different types of infinities so an object might be infinite in some ways but not in others. I hear many physicists say that the universe can be infinite and bounded at the same time. There is Gabriel's Horn as well (something finite with an infinite surface area)Gregory
    Sure, I've also heard of physicists talk about something being infinite but bounded, yet, nevertheless, these are physicists who say such things, they're neither logicians or philosophers; if they were either the former or the latter, they would've taken the care to understand that the object which they're talking about, technically, isn't infinite.

    When physicists talk about something that's infinite but bounded, they reference a circle, or some round form, as well as another thing which moves about its surface - and here's the kicker. So, when physicists talk about infinitude in this context, the circle itself that they reference is never infinite. Actually, what's taken as infinite in this context, strictly speaking, is the procession or motion of the other thing about the circle's surface, insofar as this other thing can proceed or move about the circle's surface without it ever potentially meeting an end, extremity or edge, i.e., its procession or motion about the circle's surface is potentially infinite or never-ending; for it can be supposed that this other thing can just keep on going round, & round & round the circle ad infinitum. Now understanding this, one should grasp that the circle itself is never infinite, i.e., there's no "infinite shape" in this context, but, in fact, it's the procession or motion of the other thing about the circle's surface which is taken as infinite; & which doesn't necessitate a spatial infinitude, or an "infinite shape," but a temporal infinitude, inasmuch as motion is conditioned by space & time, & not just space per se - hence, space by itself, in this context, isn't what's infinite, i.e., there's no "infinite space" or "infinite shape" in this context.

    Gabriel's horn, honestly, is not really different, because what's taken as infinite, in that context, is the rotation about the horn's surface - in other words, the revolution about the horn's surface or the rotation about the axis is what's taken as infinite, & not the object itself per se (if you consider the matter closely, I think that you should see this to be the case).

    Thus, in neither case that you've referenced is an "infinite shape" instantiated; for, again, such a thing is a direct contradiction in terms & therefore impossible. Yet, if you still think otherwise, I'm more than desirous to hear your counter-reply.

    if time is objectively an eternal instant and infinite motions hold together frozen in that instant, it seems to me the series would be geometrically infiniteGregory
    As I see it, an "eternal instant" & "motion(s)," be it infinite or not, are incompatible ideas.

    For motion can only be defined as a change of place or position; & as if it's the case that the definition of one instant doesn't differ from another, then these two instants would be indiscernible from each other & wouldn't be two instants but one & the same. Yet, as the change of place or position, or motion, necessitates differentiating between one instant from another, e.g., x in point A defines instant-1 while x in point B defines instant-2, no kind of motion(s) can involve an "eternal instant," or a changless instant that always has one & the same definition; because, again, motion necessitates a change in the definition of instants, & which therefore negates the possibility of an instant which is one & the same (or defined as such) eternally so, i.e., an "eternal instant."
  • fishfry
    2.6k
    For motion can only be defined as a change of place or positionaRealidealist

    Relative to what? If I am sitting on my couch watching Youtube videos, am I moving? Well no, relative to my couch. No, relative to my street, my city, and the earth. Yes, relative to the sun and the stars. The earth is moving around the sun, the sun is wandering through the galaxy, the galaxy is rotating and also moving through space at tremendous velocity.

    See for example this article that has the exact numbers for how fast we're moving through space. Even us couch potatoes.

    So, am I moving? And if motion is defined as a change of place or position, can you identify anything in the universe that's not moving? Even the universe is, according to multiverse theory, floating around in a sea of bubble universes. If everything is in motion, then your definition doesn't distinguish anything in the universe. It's not that what you said is wrong; it's that everything in the universe is in motion. So this doesn't tell us anything interesting. That speeding race car? It's in motion. That 200 year old statue? It's in motion too. And not just because some wokesters pulled it down :-)

    Gabriel's horn, honestly, is not really different, because what's taken as infinite, in that context, is the rotation about the horn's surface - in other words, the revolution about the horn's surface or the rotation about the axis is what's taken as infinite, & not the object itself per se (if you consider the matter closely, I think that you should see this to be the case).aRealidealist

    The surface area of Gabriel's horn is most definitely infinite. There was a long thread on this subject a while back. 17 pages worth.

    https://thephilosophyforum.com/discussion/10263/the-paradox-of-gabriels-horn/p1
  • aRealidealist
    130
    If everything is in motion, then your definition doesn't distinguish anything in the universe.fishfry
    Uh, yes, it does, precisely because, although everything can be said to be in motion or changing place/position, everything isn't, in the same context, moving in the same direction, e.g., one thing can be said to be moving to the left of another & this other thing moving to the right of the former (or, depending on the context, vice versa); thus distinguishing between movements by direction.
  • fishfry
    2.6k
    Uh, yes, it does, precisely because, although everything can be said to be in motion or changing place/position, everything isn't, in the same context, moving in the same direction, e.g., one thing can be said to be moving to the left another & the other thing moving to the right of other (or, depending on the context, vice versa); thus distinguish between movements by direction.aRealidealist

    So you agree that all motion is relative. Something is moving only in relation to something else, and not in any absolute sense. That's a lot different than what you said initially. Can you see that? If I'm sitting on the couch, I'm motionless with respect to the couch, but moving at very high velocity relative to the galactic core.

    So how can I know, using your criterion, whether I'm in motion? Or if everything is motion relative to something, of what use is your diagnostic criterion? Pick an object. It's in motion relative to something. So everything is in motion. Which happens to be true. Nothing in the universe is stationary.
  • aRealidealist
    130
    So you agree that all motion is relative.fishfry
    Yes, relative to place/position, as I've originally asserted.

    Something is moving only in relation to something else, and not in any absolute sense. That's a lot different than what you said initially. Can you see that?fishfry
    No, I can't; because I've originally said that motion is defined as change of place or position, the motion relative to a thing's place or position - which is always relative, not absolute, so it's not a lot different than what I've said initially but equivalent with it.

    If I'm sitting on the couch, I'm motionless with respect to the couch, but moving at very high velocity relative to the galactic core.

    So how can I know, using your criterion, whether I'm in motion?
    fishfry
    By determing in what context you view yourself. Relative to your couch, you're at rest, if you only take into consideration your couch & self, but relative to the galatic center, you're both in motion; yet, notice that the only way which you've determined that you're motionless, or in a state which is the opposite of motion, relative to the couch, is by not changing your place or position on it, thus inadvertently implying that motion, or a state which is the opposite of being motionless, is determined by the change of place/position. Thus you inadvertently grant my definition of motion.
  • fishfry
    2.6k
    Thus you inadvertently grant my definition of motion.aRealidealist

    Thus you inadvertently refute your own statement. You said, and this is a direct quote: "For motion can only be defined as a change of place or position,"

    But since by that definition everything is in motion relative to something, your definition is true but useless, since I can't use it to determine whether a thing is moving or not. You acknowledged that motion can only be defined relative to some other thing, you added after the fact when I pointed it out to you.
  • aRealidealist
    130
    Thus you inadvertently refute your own statement. You said, and this is a direct quote: "For motion can only be defined as a change of place or position,"

    But since by that definition everything is in motion relative to something, your definition is true but useless, since I can't use it to determine whether a thing is moving or not.
    fishfry
    Lol, are you saying that two, or multiple, things can't be moving relative to each other? So, yeah, there's no self-refutation. You just seem miss the fact that, given a determinate context, the motion of multiple things can be distinguished by their directions.

    since I can't use it to determine whether a thing is moving or not.fishfry
    How do you figure? In my previous post, I've shown that, given a determinate context, motion & rest (as the change of place/position, or the lack thereof) are easily determined. I'm honestly stupefied by this conclusion of yours. You seem to think that just saying it makes it true.
  • fishfry
    2.6k
    I'm honestly stupefiedaRealidealist

    That, I believe.

    It's a small point. But you initially made an absolute statement, and you then qualified it as a relative statement after I pointed out your error to you. So congrats on understanding what I said to you and putting in the correction. And non-congrats on pretending you thought of it yourself. You can have the last word.
  • aRealidealist
    130
    That, I believe.fishfry
    ... you should also that believe that your illogical assertion caused it.

    You can't determine what's moving on the condition that motion is defined as the change of place/position. Lol, your profundity is so overwhelming, I can't handle it.
  • aRealidealist
    130
    But you initially made an absolute statement, and you then qualified it as a relative statement after I pointed out your error to you. So congrats on understanding what I said to you and putting in the correction.fishfry
    Lol, if you really that think I've corrected myself, rather than having repeated my original assertion, this conversation is wayyy beyond me.

    You can have the last word.fishfry
    Aw, why thank you. Aren't you just the perfect combination of genius & kindness? Take care, pal.
  • Gregory
    4.3k


    Well you are wrong about Gabriel's horn. Infinite surface area with finite space within! How mind blowing. Whether this is how our universe is or if the universe has finite surface area is not known. Besides that though, an eternal instant is just my phrase for B Time. "Instant" keeps the element of time intact. An absolute flow of time is inconsistent with relativity as understood by Einstein. So if there is something objective here it would be an eternal moment and all it contains. I don't see a reason to posit anything absolute about time or space, so I stick with A Time, but my point still stands that if B Time is true and the series of past events is infinite, the universe would be infinite
  • Gregory
    4.3k


    Thanks for the reply. I don't think infinity is impossible in our universe. It just causes lots of paradoxes if not handled properly. I wish I knew the mathematics of infinity better because what could be for fascinating than comparing infinite sets!
  • aRealidealist
    130
    Well you are wrong about Gabriel's horn. Infinite surface area with finite space within!Gregory
    From Wikipedia (https://en.m.wikipedia.org/wiki/Gabriel%27s_Horn): "Gabriel's horn is formed by taking the y = 1/x, with the domain x ≥ 1 and rotating it in three dimensions about the x-axis." "Mathematically, the volume approaches π as a approaches infinity." "There is no upper bound for the natural logarithm of a, as a approaches infinity." - Thus, it should be clear that infinitude, in this context, is strictly generated by the rotation about the axis (as I've stated in my post that you're replying to); which approaches or tends to infinity but is never itself infinite. Hence, the surface area is never in fact infinite, but, like an object proceeding or moving about a circle's surface, it's approached or tended to by a never-ending revolution about the horn's surface or rotation about the axis.

    an eternal instant is just my phrase for B Time. "Instant" keeps the element of time intact. An absolute flow of time is inconsistent with relativity as understood by Einstein. So if there is something objective here it would be an eternal moment and all it contains.Gregory
    Motion is no less compatible with the idea of an "eternal moment" than it is with an "eternal instant"; the word changes, but the incompatibility remaims. For what distinguishes one moment from another, if not their content that defines them? So, if x is in point A at a given moment, then when it's in point B, this would, by definition, constitute a different moment; because two moments that are defined the same wouldn't be two different moments but one & the same, while two moments with different definitions would literally be two different moments. So, again, motion is incompatible with a changless moment that's one & the same (or defined as such) eternally so, i.e., an "eternal moment"; indeed, the change of place/position, i.e., motion, requires one moment to end, i.e., x in point A, & another to begin, i.e., x in point b, in order for it to occur, whereby neither moment (as neither what begins or ends) is eternal.

    Einstein even realized that an "eternal moment" is incompatible with, or allows no, change, which is precisely why he was lead, quite illogically, to deny the distinction between past, present, & future. "The distinction between past, present, and future is only a stubbornly persistent illusion." - Einstein

    but my point still stands that if B Time is true and the series of past events is infinite, the universe would be infiniteGregory
    Sure, if time is infinite, then time in the universe would be infinite; nevertheless, this doesn't mean that space or a shape would have to be infinite, but only the series of events.
  • Gregory
    4.3k


    If the series is infinite and each moment enfolds only to our consciousness, the fabric of the universe in it's eternal state would be infinite. The rock "now" and then "at another time" would each be all there at once so the universe, instead of being in the present, would be all at once infinite. Now you object to calling eternity an instant but how else would you describe it while keep it a temporal thing?

    Finally, there is no "potential infinity" where there is no time. If we approach an infinite surface area and it is potentially infinite to our action then it is infinite in itself
  • aRealidealist
    130
    If the series is infinite and each moment enfolds only to our consciousness, the fabric of the universe in it's eternal state would be infinite. The rock "now" and then "at another time" would each be all there at once so the universe, instead of being in the present, would be all at once infinite.Gregory
    So an infinitude of moments has unfolded to your, or everyone's, consciousness, past, present, & future? Okay, if that's so, & the present & the future are all there at once to your consciousness, then tell me with what words my next reply to you will start with. Your answer will be quite telling. & why can't people predict the future as accurately as they can discern the present, I mean, if it's all just there at once? Such a claim contradicts all of experience. Abstract mathematics has taken some people far away from reality.

    Now you object to calling eternity an instant but how else would you describe it while keep it a temporal thing?Gregory
    No, I don't object against the possibility of an instant being eternal, but I object to the reality of change, such as that of motion, being compatible with one eternal instant or moment (for reasons that I've provided in my previous posts above).

    Finally, there is no "potential infinity" where there is no time.Gregory
    Granted, a potential infinity can't unfold but in time; nevertheless, a potential infinity is still possible even if it's not unfolding, & therefore it's possible before unfolding in time, i.e., a potential infinity is still possible even if it's not unfolding in time. If it wasn't possible before unfolding in time, then it could never proceed to unfold in time!

    If we approach an infinite surface area and it is potentially infinite to our action then it is infinite in itselfGregory
    Uh, no, it's not, precisely because this potential hasn't been, nor will ever be, rendered actual (distinction between potential & actual is crucial here); no more than a potential limitation in one's enumeration of the series of whole numbers is an actual limitation, for they can just keep on going & going but without ever stopping, although stopping is always a possibility.
  • Gregory
    4.3k


    A potential infinity can't just subsist. That's Aristotle's great error, who in his ignorance lead people to think that a whole only potentially has parts
  • aRealidealist
    130
    Supercalifragilisticexpialidocious, not.

    A potential infinity can't just subsist. That's Aristotle's great error, who in his ignorance lead people to think that a whole only potentially has partsGregory
    Yes, it can. It subsists as a possibility relative to what can initiates its unfolding in time, despite its unfolding not yet having been initiated in time. To say that a potential infinity isn't possible before unfolding in time, which you maintain, contradicts the assertion that a potential infinity is even possible at all. Ironic. Also, Aristotle's point was that a potential whole is only potentially composed of parts, & not actually. Can you provide, from his writings, a citation of what you allege that he has led people to believe? I think not.

    Though, yeah, just like I've thought, you couldn't predict what the first words of my next reply to you were going to be, despite you claiming that all moments, past, present, & future, or an infinity of them, are unfolded to your consciousness. Just saying something doesn't make it true.
  • Gregory
    4.3k


    I only read the important parts of replies. A car is not just a car but the mirrors exist in their own right as things. The whole doesn't supersede its parts. The only thing potential about them is that they can be noticed
  • aRealidealist
    130
    I only read the important parts of replies.Gregory
    You mean, what you consider to be important. For what's really important & what you take to be important aren't the same evidently.

    The whole doesn't supersede its parts.Gregory
    Who's claimed, let alone implied, otherwise? You're going off of the rails. Also, just like I've thought, no citation of Aristotle leading people to believe what you've alleged that he has is forthcoming; just more bare claims. Not surprising.
  • Gregory
    4.3k


    I can tell what someone's argument is from reading a few selecting phrases. That's why I often respond to key points only
  • aRealidealist
    130
    I can tell what someone's argument isGregory
    As I far as I see it, no, you can't. Anyhow, take care, pal. Your bare assertions are leading us nowhere. However, I still thank you for our back-and-forth. Peace.
  • 180 Proof
    9.8k
    "The universe", as best as we've yet scientifically determined, seems an
    'unbounded
    finite
    expanse'
    like a hyper-torus (or hyper-sphere, or maybe even a Klein bottle). Insofar as the spacetime manifold is conceived of as a "block", it seems to be more like vibrating jello (or a cooling magma flow) than solid iron/ice.

    "Infinite past", btw, can only mean a 'negative temporal horizon' (i.e. lowest entropy-state) relative to one's inertial reference-frame.
  • Gregory
    4.3k


    Thanks, good stuff for me to research. I think it goes to show that math, philosophy, and physics can never be separated
  • Gregory
    4.3k
    Your bare assertions are leading us nowhere.aRealidealist

    No it's just that I have been in so many discussions about Aristotle and Zeno that I have gotten bored of it, particularly since Aristotle was obviously wrong and yet people defend him. If a piece of matter is infinitely divisible it has infinite parts in actuality. Again, I've gotten bored of the subject. But it is obvious that if the whole is actual and it can be infinitely divided, the parts that would separate in the infinite division are really there when the whole is together and this is the key to understanding why you were wrong about Gabriel's horn. Whether there is anything infinite in nature is debatable, but in geometry and calculus and all that it is not. There is no clear answer about whether math applies perfectly to the real world
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