Cloudscape

There can be no ultimate limits in the universe, because those limits would themselves need to have a reason to be what they are. Everything has a cause, and therefore so do physical constants; if they had not, then why could they not just as well have another value? Why do physical constants have one value rather than another, if they are purely random? There is a reason, for instance, that the speed of light is 300.000 kilometers per second, rather than 400.000 or 200.000; the same counts for every other physical constant.
The fact that physical constants are fine-tuned to life means that they cannot have been predetermined before existence; they must have been determined by existing factors. If they do have a cause, however, then that cause must be changeable. We cannot assume constants to be fully constant without dispensing with causality.
Since it would be too coincidental that there would be only one universe which is fine-tuned to life, there must be many other universes, most of which are not fine-tuned; ours merely continued to evolve because of natural selection. Something must have fine-tuned its constants. If we can find out how this happened, we might change these constants within a closed system, and so even these may not pose ultimate limits.
If all things have causes, and those causes themselves have causes, then this must essentially go on in infinity; this means that causation occurs in an infinite series. Thus, throughout this series, as everything will have random causal connections with other things, it must follow that all things are causally connected in infinitely many ways, throughout the infinite series of causations.
This means that all causes can themselves be changed; this also means that with sufficient science, all things can be observed, and that with the right technology, all things can be influenced. There can simply be no one-way causation if all things are causally interconnected, and so all causes can themselves be changed.
If everything has a cause, including physical constants, this may also mean that the universe cannot be finite. If the universe would be finite, this would mean that it possesses a certain finite amount of energy.
As this amount of energy would be specific, however, it would again be the question why it would be the specific amount it is: why one amount rather than another? If there is any such finite amount, we can only suppose that this amount would be random. Even if there were a reason that it is this specific amount, that reason would itself have been determined by other specific parameters and so forth. However, if this amount is ultimately random, it follows that its determination is acausal.
All limits, like anything else, must have a cause. If a system is limited, there must be something that limits the system; but the Universe itself cannot be limited as there is nothing to limit it. There is nothing outside the Universe to limit it, neither was there anything before the Universe to limit it, as the Universe is all that exists.

If the universe is infinitely complex, it must involve infinitely many levels both below the quantum level as above the astronomical level. All of these would have varying degrees of complexity, some of them as high as our own level. Some levels, like our own, would be able to support life. Such level could be called a "habitable level." In habitable levels below the quantum level, time would go much faster from our perspective, while in habitable levels above the cosmic level, time would go much slower from our perspective.
There is no reason why such levels would be impossible; however, if these levels exist at all, it may not be possible to connect with them. In fact, perhaps it is natural to assume that there are habitable levels beside our own just as it is natural to assume that there are habitable planets beside our own. Science has already shown us that we are far from unique; why should our level, then, be unique? Would it not be too much of a coincidence if there were only one level at which life is possible, that of chemistry? In no way we appear to live in the center of the universe; why should this aspect be an exception? Such chauvinism has betrayed us too often before to be closed to this possibility altogether.

Infinite levels of complexity below the quantum level ("subquantum levels") would mean that there are also infinitely diverse systems below it, some of which would be able to sustain higher degrees of complexity than others. Each level below the quantum level would affect the higher levels, but would do so in such chaotic ways that their effect would appear to be random.
We might never be able to observe those worlds, but although the Planck length may be the smallest size that we can observe, and therefore the smallest size that matters to us, that does not mean that there could not exist anything smaller; we simply can never connect to whatever exists at such level, at least so it seems for now.
Infinite levels of complexity above the cosmic level ("supercosmic levels") would mean the same thing. In an infinitely complex Universe (with capital U, referring to all of existence) there could be forces of infinite speed, although they might not occur except at an infinitesimal frequency; this could, for instance, bridge the distances between separate universes (which would in turn be but particles!) so that they could interact at faster-than-light speed. This would not have to be necessary for there to other levels above the cosmic level, however; suppose that nothing goes faster than light (which would, however, be very unlikely if the universe is indeed infinite in complexity), then this would merely make the interactions in supercosmic levels much slower; they could still, in effect, take place, even if there are no other forces than the ones we know already.
Since our universe expands so rapidly, it could not take part in any interactions because it would dissolve before it could do so. However, if again we assume that the Universe (with capital U) is infinite, there must be infinitely other universes (small u), and some would have density parameters which would make them stable for a long term. Most subatomic particles are very unstable, lasting only a fraction of a second; but the few that are stable are enough to form a viable level.
There are two ways in which stable universes might interact with one another: one is through forces which to us are still unknown. In that case, it is possible that our own universe has a charge we are not aware of; after all, since it does not manifest to ourselves, we cannot detect it. Indeed, if there are habitable subquantum levels, then the hypothetical inhabitants of an electron who have come to discover that they live on an electron might think it to be neutral, not seeing that there are particles beyond their own and calling their particle "the universe."
The other possibility is that stable universes interact with one another through the same forces present in our own universe. Some universes might be electromagnetically charged; even if none have a very great charge, then still, either how every universe is likely charged to some extent, even if that charge comprises only a few elementary charges. Though this is small on our level, this may have an entirely different meaning at supercosmic level. Given enough time, even the slightest force, no matter how small, will have an affect. The only thing that can prevent this is that it would be countered by another force, but those would not or barely occur in the space between universes.
Just how long this would take does not matter at all, as time is relative; on supercosmic levels, a billion years might be a very short time, just like a femtosecond is a very short time to us. In contrast, on quantum level a femtosecond is a very long time, and most subatomic particles do not survive that long.
The effects of a force depend on time as well as space. This is testified by the gravity that keeps superclusters together; certainly that force is not relevant to us, that is to say, not on our level. Time and space are relative, and what to us is a very long time may be but a very brief instant on supercosmic levels, while what to us are very vast distances may be but very short intervals on those levels.
Thus, regardless in what way or at what speed, if there are universes beyond our own then they will interact. Very slowly to us, they will move to form greater structures which in a higher level might be similar, for instance, to stars on the astronomical level — which will then again form greater levels and so on. If the speed of light is an absolute limit, the only difference this makes is that the greater levels will move slower, but even so, in that frame of reference it is not slow in itself. It must also be noted that, should there be an inhabitable supercosmic level, this slowness would also affect consciousness, so that it would not perceive its world as slow at all.

If either the age, size, energy or complexity of the universe are infinite, so are the others: if the universe is infinite in age, it must be infinite in size because a finite universe would keep expanding, ergo in energy, because it would otherwise be of infinitely low density due to this expansion, ergo in complexity because this energy would be distributed amongst the universe rather than remaining infinitely accumulated.
If the universe is infinite in size, it must be infinite in age because if it had a starting point it would originate from a singularity rather than popping into existence in infinite dimensions, and infinite in energy and complexity because it would otherwise be of infinitely low density as formerly said.
If the universe is infinite in energy, it must be infinite in age because in order to become of finite density it'd otherwise have to expand with infinite speed (this is the most plausible other possibility, as the absolute speed of light might not be absolute), infinite in size for the same reason, and infinite in complexity because of its infinite size.
Infinite complexity basically equals infinite size because size is relative. If the universe is infinite up or down, it makes little difference. Suppose the universe was contained inside a giant atom (which would have an infinitely complex substructure, so that this would be possible!), we'd still say the universe is tens of billions of light years in diameter instead of one and a half femtometer. Relative to an infinitely small world (at an infinitely complex level), everything is infinitely large. As we've said, infinite size and finite density means infinite energy. However, if the universe is infinite in complexity this does not necessarily mean that it is infinite in age.

Thus, we conclude that either:
1) the age, size, energy and complexity of the universe are all infinite,
2) neither the age, size, energy or complexity of the universe are infinite
3) the size, energy and complexity, but not the age, of the universe are infinite, and the Theory of Relativity is incomplete.

You can scratch the latter two possibilities, however, if you can accept the following argument. Existence cannot have had an actual cause, because that cause would itself have to be part of existence, otherwise it could not have existed because it would then not be part of existence. Why would there be a beginning? Where did it come from? What caused it? Now, I'm talking about the whole of existence, not just our own reality, but any reality at all, including hypothetical realities in which our own universe was created. Unless there already existed "something" which had caused the universe to arise, ie there was already something in *existence* (in other words, in the universe), such cause would necessarily have been acausal, and for something to be science it must obey causality. Causality, then, is its own only exception. Everything has a cause, but the chain of causes and consequences itself hasn't.

Following this line of reasoning we conclude that the universe is infinite in age, size, energy and complexity. This also implies a universe of infinite complexity. In such a universe, there would be an infinite number of phenomena; each of these would in some way have to influence each other, as they would otherwise not form one whole. Whatever phenomenon would not influence the rest of the Universe would not really be part of it, and therefore not really exist as far as we are concerned. In this way, all phenomena would be infinitely connected to one another, that is to say, each phenomenon would be influenced, directly or indirectly, by infinitely many others. One of such phenomena is our own will, or consciousness, which would likewise be causally interlinked to all other phenomena, meaning that it as well could influence and therefore control them. Thus, in principle, if one would find one's way through this web of causal connections, one could, in principle, control any phenomenon in the universe, meaning that one could be omnipotent. This appears to follow logically if the universe is of infinite complexity.