Time, space, infinity and anxiety

I remember thinking about space (as in “three-dimensional extent in which objects and events occur and have relative position and direction”) when I was a little kid. I asked my dad what was outside of the universe and he told me that we do not know for sure but most probably there isn’t anything. I couldn’t quite understand what he meant by that, so I asked him, and he continued to explain that there simply is no space. I couldn’t grasp that either, so I imagined that there is a very hard rock — so hard that nothing else can fit in there, and hence there is no space.

I grew older and abandoned the very-hard-rock theory. But I haven’t found a reasonable substitute for it. And it bothers me. A lot.

There simply is no reasonable possibility for space to even exist:

  1. Space is infinite and extends everywhere and never ends. I think I do not even need to explain why this sounds stupid.
  2. Space is finite. Then what is outside of it? There is no space outside. Then there is no outside. Unreasonable, too.

Please note that I am talking about space, not necessarily in connection with the universe. Just the concept of space and its infinity/finity confuses the hell out of me. And it makes me scared.

It’s similar with time. According to wikipedia, universe is the “entirety of space and time”. So, if I understand it correctly, there was no time before universe. And the universe is approximately 13.73 billion years old. Which means that 14 billion years ago, there was no time. Wait, what?

19 thoughts on “Time, space, infinity and anxiety

  1. Well, when you say „14 billion years ago“, it’s like pointing to 1,4 m mark on one meter long ruler – there is no such thing/time.

    You can imagine a finite 2D space without boundaries like a sphere. We could „live in“ a very large 3-sphere. But I don’t think today’s cosmology take it as an option.

    Maybe you could want to watch this speculative lecture: http://www.avc-cvut.cz/avc.php?id=1967 :-)

  2. Space is infinite and extends everywhere and never ends. I think I do not even need to explain why this sounds stupid.

    Actually, you do. It sounds perfectly reasonable to me…

    According to wikipedia, universe is the “entirety of space and time”.

    Well, that’s one way to define it…

    And the universe is approximately 13.73 billion years old.

    …but here, another definition is being used, obviously.

  3. Lukáš: I like your ruler analogy :) But still, how could time have begun when there had been no time before? I imagine it like this: timeless void, some more timeless void, start the time NOW. (yeah, I know that is silly)

    As for providing another dimension, it could make the universe wrap into itself, but we still have the issue whether the x-dimensional space is finite or infinite (from the point of view of someone for whom x-dimensional is usual).

    And thanks for the interesting lecture :)

  4. Michael: Ok, theoretically, maybe space could be infinite. But imagine you could teleport anywhere you want. You choose a direction and you can teleport infinitely far. And then again. And repeat it infinitely many times. It just really scares me.

  5. nice problems to think about.
    I’ve read something like “universe is finite but has no specific borders”. Imagine you have a finite space in (for example) cube and then you connect front side with back side, left with right and top with bottom. if something inside the “cube” reach one face, it will appear on the opposite face. so it can travel for infinite time and never find any borders.

    actually it’s quite similar to Lukáš Lánský’s 3-sphere.

    this model contains finite space and solve problem with borders, although I am not sure if it is geometrically possible.

  6. There seems to be a general confusion about two different levels of discourse in this debate. This despite the fact that tasuki included this very enlightening quote: “extent in which objects and events occur and have relative position and direction”. To ask what is outside our universe is to assume the existence of some metauniverse in which these two could be separated. But universe is the “entirety of space and time” so how could there be a metauniverse on a higher level?

    It can not. At least in our minds it can not. And it should not come as a surprise. There is no set theory in which the universe of all sets is a set. Mathematics can work with sets but not much with classes and the universal class is almost an occult subject. Physics observes and explains events in our universe but everything else is also just a guess and usually nonsense. Live with it. Don’t think about something you can’t think about.

  7. First, I don’t think universe is the entirety of space and time, I just quoted it because it looked interesting. I see no reason why there should be no space or time elsewhere.

    There’s a whole discipline (some even go as far as to call it science) devoted to “thinking about something you can’t think about” — it’s called philosophy.

    Physics observes and explains events in our universe but everything else is also just a guess and usually nonsense.

    This sounds a little weird coming from you. But I fully agree :)

  8. I discovered your post while preparing to leave my house. It got me interested so I tried to hastily write something meaningful and leave on time. Needles to say, I failed on the second and probably on the first account too.

    I meant to say that there are some ideas that are quite common, we talk about them, but they don’t denote any actual concept in their respective universes of discourse. I provided two examples — the universal class in set theory and the metauniverse you need for your questions in physics. To me, these are empty terms. It is, however, important to note that they are empty terms in a model of reality, be it physical reality or the ‘reality’ of abstract ideas. I rather like to think that this is the case with any questions or theories about what is outside our space or what had been before its beginning. Since we can think only in terms of models, I pointed out that all this is probably a waste of time.

    However, I wouldn’t call all of philosophy a waste of time or “thinking about something you can’t think about”. My whole argument outlined in the two posts is based on a philosophical stance which should probably be called platonism. Different schools of logic and mathematics are different based on differences in philosophical views of its advocates. If you held a strongly different opinion on this than me, you would find me just blabling incoherently. I am afraid that this might even be the case :-) But you necessarily must have some opinion on these matters. If you subscribe to classical logic and mathematics and use it to build some model, you subscribe to some philosophic opinion. Frightening, I know.

    Interesting related articles I’ve read recently:


    If you have time, read them. They are both about Goedel and philosophy and the first one is shorter.

  9. There’s a whole discipline (some even go as far as to call it science) devoted to “thinking about something you can’t think about” — it’s called philosophy.

    You shouldn’t conflate these things. On the one hand, there’s science, and on the other hand, there’s “thinking about something you can’t think about”. So-called “philosophers” have been found on either side of this line.

    6.53 Die richtige Methode der Philosophie wäre eigentlich die: Nichts zu sagen, als was sich sagen lässt, also Sätze der Naturwissenschaft – also etwas, was mit Philosophie nichts zu tun hat –, und dann immer, wenn ein anderer etwas Metaphysisches sagen wollte, ihm nachzuweisen, dass er gewissen Zeichen in seinen Sätzen keine Bedeutung gegeben hat. Diese Methode wäre für den anderen unbefriedigend – er hätte nicht das Gefühl, dass wir ihn Philosophie lehrten – aber sie wäre die einzig streng richtige.

    The right method of philosophy would be this: To say nothing except what can be said, i.e. the propositions of natural science, i.e. something that has nothing to do with philosophy: and then always, when someone else wished to say something metaphysical, to demonstrate to him that he had given no meaning to certain signs in his propositions. This method would be unsatisfying to the other – he would not have the feeling that we were teaching him philosophy – but it would be the only strictly correct method.

    BTW: I think I preview function might be in order. I have no idea whether “–” will display correctly, oh well… ;)

  10. OK, so the “–” shows up correctly, but the cite attribute of the blockquote tag isn’t displayed in any way. German quote is from the “Tractatus logico-philosophicus” of the famous philosopher Ludwig Wittgenstein, below that is a translation by C.K. Ogden.

  11. hey Tasuki

    I can understand why you would be confused. A lot of what goes for science today is really just fantasy. Maybe I can clear it up a bit for you.
    First, space is not a thing. It’s not an object. As such it does not exist and therefore it is neither infinite or finite. Only real objects can have shape and therefore size.
    Likewise, time is not a object and therfore it does not exist.
    Only objects exist. It a matter of definitions. In science, something exist if it has shape and location. If it does not, it does not exist.
    It really is amazing that so many “scientist” can’t see this, but I’m sorry to say that it’s true. People confuse concepts with psysical object all the time. Concept is defined at that wich refer to two or more objects. The concept never become psysically real. Even if the object it refer to exist, it still just a concept. Time is just an reference to movement. An easy test for finding out if something exist is, can you point to it or can you draw realistic picture of it.
    I hope i made a litte sense of it all for you.


  12. niin,
    it amazes me that you call the things you’ve written about science. Obviously, non of this questions is decidable or falsifiable (and therefore its not science by the very definition) and is only a matter of definitions and personal philosophy (eg. some people think that the world really doesn’t exist and everything is only creation of one’s mind, etc…). As for the shape and location… Tell me then, what is a shape and location of a photon field in quantum electrodynamics. Or doesn’t it exist by your definition? ;-) In fact, your definition of existence is pretty lame even in classical physics context ;-) Only way it could stand on its two weak legs would be in some weird philosophical worldview, but this, again, is no science at all, it’s more like a religion — ‘There shalt exist but things with shape and location and thou shalt not doubt it!’ ;-)

    as for the things like 13.7 billion of years… One should carefully understand what is meant by this. This just refers to the one of the results supported by general relativity. As you can see, it already assumes a philosophical worldview (a world can be described by physics) and further, that it is described by general relativity (on a larger scales we know this to be very true) so the universe’s age refers just to the one information about spacetime (like a width, or height of an object, if you remember that space and time are related in relativity) which is really just model of the universe. And by model I mean a mathematical device that describes processes that can actually be measured!

    As for the questions like ‘What’s outside of this universe/spacetime?’ — they simply have no meaning. Why? Because you’ve already assumed you can describe the world by physics and in fact you have described it pretty well using the spacetime model. So questions like that really shouldn’t be asked if you know what you’re talking about. Problem is, people outside the physics community just like to talk about things like the age of the universe without really understanding the concept of physical theories behind it.

    To sum it up, either please understand that you’re using physical theories and therefore are not allowed to ask some stupid question or you can dispose of physics entirely and assume whatever worldview you like, but please make sure to not mix it up with any physical information like age of the universe, etc… ;-)

    Hope this helps ;-)

  13. Marak,
    You say my definition of existence is lame, but I can see that you failed to provide a better one. Calling me religius is pretty funny. I don’t believe that concepts are real like many scientists do, they are the ones that are religious. And so are you, if you think that concepts exist physically.
    Concepts are fundamentally different from objects. Concepts can’t do anything. Only objects can do anything. In science, explanations must be buildt on objects. Any explanation that uses concepts to cause object to do anything is not science. If you want to use concept in a model, that is fine. But don’t call it science.
    Many people confuse science with modeling. Models are frameworks that people can use as a shortcut to building things or making choices. Models don’t explain anything, they are just a model. Science is about explaining things, not modeling them.

    Scientist say that a photon have no shape. Therefore, photons don’t exist and is just a concept. Physic is the science of existence. The photon has no place in physics.


  14. Hi again niin,
    sorry if I have to get into a bit philosofical discussion here, I usually prefer working with a nice physical framework, but I see it is inevitable at this point.
    I think you have a serious problem with understanding very foundations of logic. As I pointed out in my previous comment, it is not necessary to even assume that world is described by physics. There always need to be some axioms, you can’t prove everything, so pretty much everything boils down to individual religion/worldview. Therefore, there can’t ever be reasonable _and_ unique definition of existence. Every definition depends only on the personal worldview.

    _Howerer_, if you assume the world actually _is_ described by physical laws (which I guess most of us intuitevely do), then your definitions have to be such that they match the experiments we make and theories we use to explain them. Therefore, your definition of existence is unphysical. I am not aware of any better one and I am not even sure there is need of defining it. However, please read on, I will elaborate more on it later on.

    I don’t agree with your definition of modeling at all. Science (and as a main representative of science, physics) is by its very definition an attempt to explain the processes we see around us. The general method is:
    1. Do experiment
    2. Examine the results of the experimnt
    3. Create a theory/model that would explain the results (and of course also the previous experiments)
    4. Do more experiments to test your theory and its implications
    5. And so on…

    So you see, all of science boils down to two main points: making experiments and creating theories (which is really just another world for a model). We won’t be ever able to find out how nature works. We can only interpret what we see/measure. And by Heisenberg’s uncertainity principle, measurement has it limits too. There is only so far we can go in understanding the nature. Therefore, there is no need to even define existence of things in physics. But if you really want to say something exist, you can say that objects in your theory exist (that is really the best we can do!).

    Of course, different sciences proceed differently, because they are usually not as fundamental as physics is.

    Sigh, your last paragraph again sounds like a religous chant :-(
    At least please tell me where did you learn that physics is a science of existence. I am a physicist myself and haven’t heard this yet from any other serious physicist. Probably because it’s a total bullshit ;-)

    But I guess I am just losing my time here after reading your last sentence. Anyone who denies the importance of photon in modern physics is either a complete ignorant or a religous crackpot. Don’t know which one is worse…


  15. Marek,
    You make no sense when you say that physics doesnt necessarily describe the world. Physics is not about describing but about explaning. Models describe, physics explain.

    This is the real method in science.
    1. Hypothesis (assumptions)
    2. Theory (explanations)
    3. Conclusions (opinions)
    There is more to each step, but no-where is experiments required. Fields such as archeology, astronomy and history couldnt be science, if this wasnt true.

    You criticize me for my opinions about photons, but you fail to point out where Im wrong. If you cant spot any errors in my logic, then you only need to prove to me that the photon isnt a concept and then I will change my mind. You can start by telling me what shape a photon has. If you cant then your belief is the same as people believing in god.

    The basis of any religion, rest on the confusion of concepts with objects. Religious people think that an abstract concept is just as real as a living room table. Without this confusing of a concepts with reality, its not possible to be religious. That is why its very important that we dont confuse concepts with objects in science. Otherwise you become religious. Which means that you are wrong.


  16. Niin,
    what I meant is that everyone can believe what they want. If they believe that they live in a matrix and all their sensory input is just a computer program, there is no means of ever proving them wrong (nor is there a need to it). This is what I meant by “world is not necessarily described by physics”. That is because foundations of every worldview rest on each and every one’s personal axioms that can’t be ever proved.

    However, physics really is not about explaining how the world works. Only thing physics explains are the results of experiments. What we see and how the real world really works are very different things that people often confuse. There is no need for physics to explain the world (and as I pointed out in my previous comment, it maybe even can’t ever be done, because of the fundamental limitations of physics on a quantum level as we know it today). That is why all physics does, is predict the results of the future experiments. Therefore, physics is actually describing the world and what we see and not really explaining it (although you can play with words if you will…).

    Your real method of science doesn’t make much sense to me. In what part of it is experiment, which is the single unifying and most important point of all sciences? You can theorize however you want, but if your theory can’t be tested with experiment, it’s worth less than nothing. With one exception and that is mathematics, which doesn’t need experiments, it just produces theories valid per se for use in other sciences (from the point of view of applied mathematics). But I assume we talk other sciences here and _mainly_ physics. For physics, what I’ve told in my last comment is the scientific method (experiment/theory/experiment/theory/ad infinitum…). If you are not a physicist, please just believe me. For other sciences, as I pointed out, the process is somewhat different, because it deals with less fundamental aspects of life, but still, the basic theory/experiment dichotomy is the same. If you are an archeologist and you claim that human has evolved from a bird (a theory) you better try to confirm it by finding bones of half human/half bird and other relics (experiment). There is really no other way and anyone who thinks he can produce theories without verifying them is not a scientist ;-)

    I don’t get the difference between hypothesis and theory. In my opinion they are really the same thing. Both are the results of thought in an attempt to describe or explain something and both can’t be proved, only tested for validity by experiments. In this view, they are the same. But maybe you have some other definitions for these two terms. If so, be so kind as to tell me what they are!

    The basis of any religion is no different as basis of any other worldview! It relies on fundamental set of axioms that can’t ever be checked. I cannot really prove the physics really works, or that I live in matrix, or any other scientific or religous worldview. All of these are equal and can’t be distinguished by pure logic. They are just a matter of porsonal choice ;-)

    And what makes you think a living room table is real? You are religous in the same way other people are, you only choose to assume different concepts (living table here) are real. Please contemplate on this ;-)

    Religous doesn’t mean wrong. You clearly don’t understand logic, axioms, deduction and other important concepts, to understand that religion is no different from any other worldview. The only difference is that you really can’t mix different worldviews together, much as you can’t mix some mathematical theories because you can get to a contradiction. That is why scientific people frown down on religion (you can’t really believe in a god, when you have already classified all forms of matter and pretty much described the world around yourself and didn’t find any real need for god). But it’s really the same from the other way around. If you are religous, you can frown down on scientific people. But both groups are absolutely equal. It is just important not to mix the two together ;-)

    You want me to tell you the shape of the photon and then point out that if I can’t my belief is the same as those of religous people. It exactly is! Finally you maybe start to undarstand, that to believe in existence of physical theories that describe the world is the very same thing as to believe in god. I know this very well and am not ashamed by this in view of what I’ve written up to now ;-)

    In the end, it seems to me that you are a philosopher with fixed worldview and strict definitions of every term which aren’t really able to encompass all of different uses of those terms in science. Please try to contemplate a bit on what I’ve written. I think I don’t have anything else to add. If you still disagree with me, try to point out where my logic fails, I tried to be as clear as I could.


  17. Marek,
    I do consider myself a philosopher. You sound dangerously like a nihilist.
    It’s not valid to argue that the senses are invalid, because you always use your senses when you argue about that. The argument self-destructs. That means that everyone who argues automatically accepts that the senses are valid. Including you. Otherwise you declare yourself crazy and not worth listening to. So which is it?

    You still don’t make any sense with the thing about science only describing things. Why not just call it modeling and forget the word “science”. It seems more fitting to what you are actually doing. Then you can let us serious pursuers of truth use the word “science” so it’s easy to tell when there are actually some truth to what we are saying. If you wanted to brand your models a little better, you could call them science inspired models, but don’t call them science. Because that would be misleading. You said yourself that you didn’t care about truth but only about describing things.

    One of the benefits of not ascribing to the experiment definition of science is that you don’t have to believe in anything to say that something exists. In science we start out by defining words in the hypothesis stage. So if we have a definition of an object, then we only need to see if the object’s characteristics match the definitions. If it does, then it exists by definition.
    I can see a table in my living room, it has shape, it has location, it matches the definition of a table, and therefore the table exists. There is no need to experiment, no need to believe. The table exists even if I don’t observe it. There is no need to invoke belief in science.

    I’m glad that you admit that your photon model is just as valid as the belief that Jesus walked on water and roused from the dead. It makes it easy to judge how valid it is. I think ill rank it below belief in Santa Claus. At least you could draw a picture of him. ^_^


  18. Dear niin,
    I certainly don’t use senses to argue about things. I use my brain. I encourage you to do the same, it would really help this discussion ;-)

    But I don’t believe this conversation is leading anywhere. I really have no business talking with someone who is saying that physics is not science. Also, I am not sure you have seriously thought about anything I’ve written and you just aren’t able to use logic correctly as I see it.

    Regarding the photon, you didn’t get it at all, did you? All I said is that I believe in physical framework. If so do you (and I will assume you believe physics works) you are mocking yourself also.
    Very well then, I will explain photon to you. You see, in modern physics, there is a thing called quantum theory. It can be shown, that objects don’t have a clearly defined position (as it can be measured). All we can get from quantum theory are the probabilities of measuring some variable. Therefore, from the point of quantum theory there is no such thing as shape. That would only be a classical idea which is why I made fun of you in the first place, because your definitions clearly come from the place that has no real touch with physics. It turns out, in quantum theory, all things are like this, only when they get bigger, the probabilities go higher to find the object at one certain place as opposed to it being spread over a region. Therefore you can define your shape here. However, there is no distinction between “things with shape” and “things without shape” in quantum theory. They are treated on equal footing. Also, ordinary matter is composed out of atoms. I hope you know at least that much. Atoms are composed out of nucleons and electrons. Those are particles of matters. However, there are also particles of field tying them together present (photon, gluon, W+/W-/Z bosons) which are again treated on equal footing with matter particles like electron or quarks. Therefore, if you at least believe in atomic hypothesis and quantum theory as any sane man would do, then you have to admit photon is just as real as any dining table. However, by your definition, photon doesn’t exist because it has no shape. Oh my, we have arrived at contradiction, and all because of your lousy definition. Why oh why is it so? ;-)


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