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Silly Druid

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  1. Silly Druid

    Do Extra Dimensions Exist?

    By Silly Druid,


    Physics
    (Sorry for posting this 2 days later than usual.)
    In some physical theories there are not only the 4 dimensions we know (3 space and 1 time), but also some small extra ones. But they hasn't been observed yet, so do they really exist? Well, there is a very convincing argument (for me at least) that they do. It's called "CPT symmetry".
    Symmetry is a very important concept in physics, it means that some differences between two systems don't really affect the way they work. For example the "translation symmetry" means that the place where something is located is not important for its physical evolution (if all other conditions are the same).
    So what do these 3 letters mean? C is "charge symmetry", which means replacing all matter with anti-matter and vice versa. P is "parity", and means making a mirror image of the universe, and "T" is reversing the direction of time. The interesting thing is that individually all these symmetries are broken (not very strongly, but there are some subtle physical effects that don't obey them), but the combination of all three of them, as far as we know, holds. It also means that combinations of two of them are also broken, and are equivalent to the third one, for example CP = T.
    Without the extra dimensions, all this doesn't make much sense. The P symmetry is about space, T is about time, and C is about... some numbers we attribute to the particles to describe how they interact with each other. But, the extra dimensions that appear is some theories (starting with the Kaluza-Klein theory, and including some newer ones, like the string theory) are used to explain the charges as movement of the particles in these extra dimensions (which, due to their small size, is quantified, that's why the charges have discrete values).
    Making a mirror image (P symmetry) can be viewed as reversing all 3 spatial dimensions, T symmetry is reversing the time dimension, and if there are extra dimensions, then C symmetry is also reversing them. So, in other words, the CPT symmetry can be interpreted as "if you reverse all the dimensions, it's like you reversed none." So it all starts making sense, by grouping 3 similar symmetries into one. Coincidence? I think not.
  2. Silly Druid

    The Nature of Time

    By Silly Druid,


    Physics
    What is time? According to physics, it's just another dimension. There is a slight difference between spatial and time dimensions. Basically, the distance across two or more spatial dimensions is the square root of the sum of squares of the distances in the individual dimensions (as in Pythagorean theorem). But, due to time being a different kind of dimension, the distance across a spatial dimension and a time dimension is the square root of the difference of squares. Also there is only one time dimension, and three spatial dimensions. (There may be also some small extra dimensions, more about that in a future entry.)
    In Einstein's General Theory of Relativity the universe is a four-dimensional object, and the thing it's made of is called "spacetime". Quantum mechanics, especially my favorite interpretation of it, called many-worlds interpretation (another subject for a future blog entry) makes it more complicated, because the universe seems to "split" every time something random happens, so it becomes a very complex fractal-like object. Anyway, there is nothing in the current physical knowledge (that I'm aware of), that would suggest that the passage of time is a real thing. The universe as a mathematical object just exists, which suggests that the flow of time is an illusion, it's how we perceive it due to the way our brains work, but it doesn't really happen.
  3. Silly Druid

    Free Will Makes No Sense

    By Silly Druid,


    Philosophy
    So, for some people (I think I'm using 'some people' too much in this blog) free will is a very important thing. They feel that if everything is deterministic, then it's already decided what they are going to do, so they can't decide it themselves. It's like something is forcing them to do things, and they don't have a will of their own. So determinism is a bad thing, and free will should exist to make the human existence meaningful.
    This is wrong.
    We are a part of the universe, and the laws of physics affect us the same way they affect everything else. And if we ask why something happened, there are only two options: either it depends on something else (so it's deterministic) or it doesn't (so it's random). When we make a decision, we can take many things into account, but in any case, it depends on something, so it's deterministic. There can be also a small random factor due to quantum processes in our brains, but even if decision making is completely deterministic, and everything that happens in the future is already decided (more about that next week), then it's still our decision, and no one forces us to do anything. So the entire concept of free will is pointless, it's one of these things that make sense when you don't think about them, but when you do, it doesn't.
  4. Silly Druid

    Do We Live in a Simulation?

    By Silly Druid,


    Philosophy
    Some people argue that advanced civilizations should be able to run simulations with beings like us in them, and, due to the fact that one civilization can make many simulations, and there can even be simulations within simulations and so on, it's most likely that we live in one of these simulated realities.
    My approach to this question is related to the subject of my last week's entry: consciousness. Can simulated beings be conscious? Well, for those who think consciousness requires only a specific type and/or amount of information processing, it is perfectly possible, but, as I explained, I don't believe so. What I believe is that one of the possibilities below is true:
    1. Consciousness can't be simulated at all. It can do something a Turing Machine can't, so it can't run on a computer. (As for quantum computers, correct me if I'm wrong, but I think they can't do non-Turing things, they just do some things much faster.)
    2. It can be perfectly simulated, but it's not real. So, the simulated beings behave like they are conscious, but in fact they aren't.
    So I think we probably don't live in a simulation.
    Next week: Free Will Makes No Sense
  5. Silly Druid

    But What is Consciousness?

    By Silly Druid,


    Philosophy
    (This blog entry is the longest of all that I made so far, but it's about something very important to me, so I need to be thorough with it.)
    That's a hard question. Actually I think it's the hardest question of all. We don't have a mathematical or physical equation to describe consciousness. So, let's try to use a very powerful tool, that is able to explain almost everything in our universe. It's called reductionism.
    What is reductionism? It's a process that is used very often in science. It means explaining the functions of a whole by the functions of its parts, including their interactions with each other and the outside world. It can be used repeatedly to reach the most basic known elements of the universe. Let's consider a tree for example. To figure out how it works, we can use our biological knowledge to define the functions of its cells, and explain how they interact and make up the whole thing. Then we can explain cells by the chemical reactions of molecules within them. Then we explain molecules using atoms, atoms using protons, neutrons and electrons, and protons and neutrons using quarks. That's the most basic level of our current physical knowledge, maybe there is something even more basic behind it, but we don't know yet. (Note that reductionism is good at explaining things, but usually not at exact predictions or simulations of their behavior, because often the complexity of the system is too big to make such simulations feasible. So most mathematical models that are actually used for such purposes, for example weather predictions, are a simplified version of the system, rather than an exact representation of its parts.)
    So now that we know how reductionism works, let's try to use this procedure on consciousness. Can we reduce it into something more basic? In fact we can. It's called "qualia", the single "feelings" that make up our whole conscious experience. But that's it, we can't get any further. We know that qualia have something to do with the activity of neurons in the brain, but we have no idea how to make this connection. I think it's the biggest problem in all science, and my answer to it is that there must be some currently unknown physical process involved here.
    But maybe, as some authors suggest, consciousness is an emergent phenomenon? Well, let's say it's emergent so we don't have to explain it. Problem solved... or not. First we need to know what an emergent phenomenon is. For example, let's consider the movement of air molecules. Depending on conditions, it can be just random, or all of them can be moving roughly in the same direction (in this case we call it "wind"). But sometimes we can see interesting patterns in it, for example with some kinds of rapid circular motion we call it a hurricane. It's a typical emergent phenomenon, because a single air molecule can't make a hurricane, we need a very large amount of them to create it. And it has some specific properties that we can study, so we consider it a thing on its own. But on the basic level it's still movement of air molecules, so "hurricane" is just our interpretation of a large scale pattern in this movement. That's how I understand emergence - it's our interpretation of some patterns in behavior of some more basic elements.
    So, let's assume there is nothing mysterious in the workings of a single neuron, and consciousness is an emergent phenomenon that appears when a large number of them are working together. For some people it's a very good explanation, but I can see a problem with it. It's kind of hard to explain, but I feel that consciousness just exists, regardless of our interpretation. So it can't be composed from some basic things that have nothing to do with it. But maybe it doesn't need neurons specifically, but it's just associated with complex information processing in general? Well, "information processing" is something similar to an "emergent phenomenon", it's just our interpretation, while actually some basic physical processes are happening, for example when we use a computer, we see it as information processing, but actually it's just movement of electrons in semiconductor materials. I just can't see the connection between these kinds of processes and consciousness, or how it could "arise" from them, so I'm sure there must be some "new physics" involved. Of course you can disagree with me, but that's how I feel about it. Also I feel that I explained it badly, but I have no idea how to do it better.
  6. Silly Druid

    What Makes the Difference

    By Silly Druid,


    Philosophy
    Continuing the subject of multiple universes, I think we can divide them into two kinds: those that have 'observers' in them (probably the minority), and those that don't. The 'observerless' universes exist (at least I believe they do) only to satisfy the principle I wrote about two weeks ago, that any logically consistent system exists, because there is no reason why it shouldn't exist. But does its existence really matter? I think it doesn't, because if there is an universe and there is no one in it to experience it, then it might as well not exist, and no one would notice.
    But what are these 'observers'? I think they are instances of the most mysterious and perplexing phenomenon I know: consciousness. It makes the existence of a universe significant, because the beings that have it can really 'feel' (whatever it means) the physical world around them.
    So, in conclusion: Consciousness is a fundamental property of the universe that makes the difference between existence and non-existence. But what it really is? We'll try to figure it out next week.
  7. Silly Druid

    The Anthropic Principle

    By Silly Druid,


    Philosophy
    This time we're going to figure out if there's anything special about our universe, but let's start with another question: Do we live in a typical place in it? By 'typical' I mean the kind of place that we will most likely end up with if we pick one at random. The answer is of course not, because a typical place in our universe is just empty space. And we happen to live on a planet where there are good conditions to support life. And the reason why it is so is obvious: as far as we know, in the empty space there are no intelligent beings that would ask such questions.
    So, if you believe (like me) that there are multiple universes, is the one we live in a typical one? Analogically to the previous question, the answer is no, because most universes probably don't have any intelligent life. It requires very precise fine-tuning of the physical constants to make a universe suitable to support life, and according to the current scientific knowledge there's no reason that the constants must have these specific values. So it seems likely to me that there are universes where the constants or even the laws of physics are different, but most of them don't have any complex structures in them. I'm not saying that our universe is the only possible one that can support life, probably there are many combinations of laws and constants that enable it, but still these are only a small minority of all possible universes. So our universe is one of these 'special' ones, just because it makes it possible for us to live in it.
    But what really is the thing that differentiates these special kind of universes from all the rest? Is it the existence of life, intelligence, or something else entirely? I'll answer this question next week.
  8. Silly Druid

    The Big Question

    By Silly Druid,


    Philosophy
    Welcome to my blog. I'm going to cover a wide range of philosophical and scientific topics here, but don't expect walls of text, my goal is to make the entries brief and straight to the point. I welcome discussions and feedback in the comments, as well as suggestions what I should write about in the future. We'll start with the most important question in philosophy: Why does anything exist at all?
    My answer to this question is simple: Because why not? In other words, there shouldn't be any arbitrary rules that would determine what exists and what doesn't. The only rule that I can accept is: What can exist, exists. So what does "can exist" mean? I think it means it must be logically consistent, because logically inconsistent systems can't exist for the simple reason that their nature is not well defined.
    Do we have a language to describe logically consistent systems? Yes, we do. It's called mathematics. Which explains why the laws of our universe are mathematical in nature: Because all logically consistent (which means mathematical) objects exist, and our universe is one of them. But is it just a random one, or there's something special about it? I'll answer this question in next week's topic: The Anthropic Principle.
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