Momentum

[demagogue]

Well, obviously nobody does remember it, so where's the difference to living just this one life? smile.gif

 

Living it an infinite number of times.

 

Nietzsche liked this idea so much because he thought you'd damn well make good decisions if you thought you were making them for eternity. Pretty much captures what existentialism is all about.

 

I mean, you may not remember living before, but if you knew that you had*, the not-remembering part would be even more ominous. You don't know what's coming, but it's inevitable. Amor fati.

 

 

* I guess for this I mean, you know the math supports infinite time and quantum fluctuations ensure every physical possibility at some non-zero probability , and you are ensured the universe keeps "living", through infinite expansion or black hole recursion or compactification, take your pick ... if you have those assumptions, you are virtually absolutely guaranteed to have all of this repeated, and infinitely so, along with every variation.

Edited May 30, 2007 by demagogue

[sparhawk]

If I live through all variations it doesn't really matter which choices I pick, because I will also live through all the conseqeunces.

 

Nice thing is, that there is somewhere a variation where I'm a genius at math.

[demagogue]

Yeah, but then those variations aren't "you".

 

Or are they???

 

Or what does it mean to be "you", anyway?

[greebo]

I never got the hang of these philosophical (rhetorical?) questions - I feel they don't help me in any way.

 

I don't understand what math should have to do with it either. Same goes for physics - what are "quantum fluctuations" supposed to be?

[Vadrosaul]

Woah, this is reminding me too much of the Matrix discussion between Neo and the Architect.

[sparhawk]

I never got the hang of these philosophical (rhetorical?) questions - I feel they don't help me in any way.

 

I don't understand what math should have to do with it either. Same goes for physics - what are "quantum fluctuations" supposed to be?

 

Math helps a lot IMO. In fact I started to learn this physics stuff and I have been reading university level books now for at least two months (yeah, I know it's not much but I have to start somehwere ) because I want to learn the math and understand it. In fact I have read a lot of books on laymen level, but it becomes increasingly unsatisfactory. All these books explain essentially the same things, and making claims about properties of special and general relativity and other stuff. I found it exceedingly frustrating that I read these books, and had to take their claims at face value because I couldn't verify what's behind it. Especially with string theory I'm quite dissatisfied, the more I read about it, because I got more and more the feeling that this is no longer science. So I decided to learn the math (at least as much as I can) and see for myself. The experience is quite interesting. So far I already started to get a much better understanding at least of general relativity, and it really helps a lot. I was also quite surprised that I found a lot of the math rather straightforward because I learned similar things a few years ago for game programming. And it was really a cool moment, when I learned these math a few years ago without understanding it really, and suddenly it makes sense, because the same formulas (or very similar ones) are used in physics as well and there they get some meaning.

At least for general relativity you can definitely get a good understanding just with high school math and some understanding of calculus and vector algebra. It's probably harder for quantum physics, but I see that when I get there.

 

Also a nice side effect is that I suddenly can make sense of some of the postings that Ishtvan writes. He is no longer speaking gibberish to me. OK, two months is not THAT much, but I definitely can see an effect in my understanding and see the difference to before, so that alone is worth it for me.

[sparhawk]

Yeah, but then those variations aren't "you".

 

Or are they???

 

Or what does it mean to be "you", anyway?

 

I often think about this. If somebody would create a perfect copy of me, down to the last molecule. What happens. I'm sure that this guy would be me, with all my memories, but it would still be a different person as well. A strange thought I think, because even though it would be me, I would not be able to feel this guy as I do me.

[greebo]

That's not quite what I meant - I don't get the connection between math (let alone quantum physics) and the question whether we live once or multiple times.

 

Also, it's a bit funny that people always aim at special (or general) relativity when they want to learn about physics. There must be some coolness factor about it.

[sparhawk]

That's not quite what I meant - I don't get the connection between math (let alone quantum physics) and the question whether we live once or multiple times.

 

Ah! OK. This was a missunderstanding then.

 

Also, it's a bit funny that people always aim at special (or general) relativity when they want to learn about physics. There must be some coolness factor about it.

 

I think there are several reasons, but I can only explain mine and assume about the others.

 

One of the reasons is probably that relativity is pretty famous, as opposed to the more exotic physics theories. I bet that many people never heard QCD, QED, conformal theory, technicolor, etc. but virtually everybody has heard about relativity.

Another reason might be, that realtivity is explained in each and every book about physics for laymen, which I already find quite boring. Pick up any book on cosmology or other relation to physics and you most certainly find at least one chapter with a "brief history" where (usually special) relativity is explained.

Still a nother reason might be that at least special relativity can be understood with rather simple math. Vector algebra and calculus.

 

That was not my reason though. I read about relativity the first time when I was about the age of 15 or 16 and got interested in this topic. Especially the time dilation and space contraction was something that I tried to understand, but I never really pursued it. So when I started to more seriously learn physics now, you start with classical mechanics coming from Newton, and from there it is a rather short step to special relativity. I still have to get back to the chapters of momentum and angular momentum because I sure had problems with these, but the concept and math for special relativity was rather straightforward. And it was quite an interesting experience for me to see where the effects are coming from. Before that I always had to accept the claim of time dilation and space contraction, but now I know why this is the case, assuming that the Michelson-Morley experiment is correct. So special relativity is one of the starting points and of course, the farther you get the thinner the air gets, and you find less poeple who can make sophisticated enough claims about it.

[Ishtvan]

At least for general relativity you can definitely get a good understanding just with high school math and some understanding of calculus and vector algebra. It's probably harder for quantum physics, but I see that when I get there.

Basic quantum is not that much harder math-wise. You might have to know a bit more linear algebra and differential equations, basically understand eigenfunctions. There's a good "algebraic approach" that starts with "postulates" of QM. I don't remember what they all are now, but it's stuff like everything is described by a wavefunction, an observable is an eigenvalue of the wavefunction operated on by some operator, etc. For some people that is not pure enough, but I found it helpful to learn things and be able to solve problems.

 

I'm having to do some hairy solid-state optical absorption calculations right now, which is rather frustrating since I'm not a real physicist, but with the right approximations it basically reduces down to integrating sinusoids and exponentials multiplied by eachother.

[demagogue]

That's not quite what I meant - I don't get the connection between math (let alone quantum physics) and the question whether we live once or multiple times.

 

One part of quantum physics is that there is a non-zero probability of essentially any physically possible interaction. So, e.g., there is a non-zero probability that a 747 jetliner will spontaneously form in your backyard, with a probability you could actually calculate (granted it's a very small probability). If you add the assumption that the universe is infinite in duration, one way or another, then you have the law of big numbers, a mathematical idea which says that, as long as you have a non-zero probability, the longer time you have to wait for it, the more likely even the most unlikely things will happen, until you reach eternal time, in which case, so the principle says, all non-zero probabilities are integrated essentially up to 100% likely.

 

Adding these two ideas together, you come to the conclusion that the physical events that make up your life have a non-zero probability of occurring in their same sequence again, and there's enough time/opportunity to allow it to happen, so it will happen. It's about the same as the argument that somewhere in pi is your genetic code encoded as numbers, or your life story, or any sequence you want ... and that exact sequence (no matter how long it is) is not just there once, but an infinite number of times ... the deeper you go, the more likely, and since it's infinitely long, 100% likely.

 

Like most mathematically driven arguments, though, it smells a little fishy in the real world (the "infinite lives" argument, I mean; the "any number in pi" argument is solid). But it makes for a fun thought experiment anyway.

 

 

 

Also, it's a bit funny that people always aim at special (or general) relativity when they want to learn about physics. There must be some coolness factor about it.

 

Relativity is "cleaner" than quantum physics. I think one of its big advantages in the PR department is that it's so geometry-focused, you really have a concrete image you can focus on. Also, because SR and GR both present you with such WEIRD ideas which seem insane when you start considering them. It's like when you spill puzzle pieces on a table, you look at them and you first think, there's no way this is going to all fit, but as you slowly piece them together, it all fits together like magic, and the whole image emerges before your eyes, that's very fun to watch work out! Space contraction + time dilation = the same speed of light in every moving frame of reference; it actually works! The energy density (like the overall pressure) at the center of gravity of a mass = exactly the way particles flying around the mass will bend around it; you know one, you automatically know the other ... they are on two sides of an equals sign. Talk about diving into murky waters and coming up with a fish with that idea! There's nothing intuitive about it, but it all works out.

 

With quantum physics, you can get an idea of how the equations work out, but after so much reading you're still not sure what you're really looking at. It's just not as gratifying a feeling ... more bewildering. Although, then again, it's very weirdness that just refuses to resolve itself (like it does with relativity) is some of its charm.

Edited May 31, 2007 by demagogue

[sparhawk]

One part of quantum physics is that there is a non-zero probability of essentially any physically possible interaction. So, e.g., there is a non-zero probability that a 747 jetliner will spontaneously form in your backyard, with a probability you could actually calculate (granted it's a very small probability). If you add the assumption that the universe is infinite in duration, one way or another, then you have the law of big numbers, a mathematical idea which says that, as long as you have a non-zero probability, the longer time you have to wait for it, the more likely even the most unlikely things will happen, until you reach eternal time, in which case, so the principle says, all non-zero probabilities are integrated essentially up to 100% likely.

 

IMO this is a rather good argumnet AGAINST the universe being infinite in time. If that were the case, we should observer such phenomenons occassionally. Esoteric people claim that this actually happens and is reported as ghost sightings and such, but no such report stands up to scrutiny, so I can discard them. With the absence any such events being reported, I think we have a good chance that we are not living in such a a universe IMO. I know that such a probabillity would REALY be VERY small, but even so, the chances that were were living right now in a version of a universe where no such thing happens is IMO even smaller.

 

Relativity is "cleaner" than quantum physics. I think one of its big advantages in the PR department is that it's so geometry-focused, you really have a concrete image you can focus on.

 

Yes, that's right. Going with guts feeling, I have a hard time believing in QM. I simply don't think that the universe is THAT complicated. I have no problem accepting that it can be strange, but QM stays quite sane, while QM does not.

 

Also, because SR and GR both present you with such WEIRD ideas which seem insane when you start considering them.

 

With relativity I have no such problem and I find it quite straightforward. I wonder wether I will think the same about QM, once I get to that area.

 

Although, then again, it's very weirdness that just refuses to resolve itself (like it does with relativity) is some of its charm.

 

But I don't think that this makes a strong argument for it.

[greebo]

One part of quantum physics is that there is a non-zero probability of essentially any physically possible interaction. So, e.g., there is a non-zero probability that a 747 jetliner will spontaneously form in your backyard, with a probability you could actually calculate (granted it's a very small probability).

Where did you get that conclusion from? You're sure you're not talking about thermodynamics here?

 

If you add the assumption that the universe is infinite in duration, one way or another, then you have the law of big numbers, a mathematical idea which says that, as long as you have a non-zero probability, the longer time you have to wait for it, the more likely even the most unlikely things will happen, until you reach eternal time, in which case, so the principle says, all non-zero probabilities are integrated essentially up to 100% likely.

I think you're referring to Kolmogorov's zero-one law here, which basically says: If it can happen, it will happen, just you wait. Problem is, the universe doesn't appear to be inifinite in duration (around a dozen billions of years, but I'm not sure about the exact numbers here).

[sparhawk]

Where did you get that conclusion from? You're sure you're not talking about thermodynamics here?

 

Probably from the tunneling effect or from the spontanous particles.

[greebo]

You won't really get a 747 in your backyard just with tunnelling effect.

[sparhawk]

No, but with spontanous particle creation. I've made enough room in my backyard so I wont get any problem as soon as it appears. Now I'm waiting for it to happen. I wonder how much I will get for it, when I sell it.

[greebo]

Forget the selling price, you should rather think about the patent. Heck, you'd make a fortune, hurry up!

[OrbWeaver]

I'm not a physicist, but I suspect the "materialising 747" conclusion from quantum physics is based on the same layman's misunderstanding of science as the belief that higher-quality CD-R media leads to better quality sound, or that putting Premium Unleaded 98 petrol in your city runaround car will improve its performance.

[sparhawk]

Now that I think about it, the only reference to a "materialising 747" I seem to remember comes from evolution discussions. Refering to the argument that, no matter how often you throw the screws and other material in the air, there will be no 747 coming from it.

 

Another argument comes from thermodynamics. It is more probable that the universe was created only a splitsecond before with all your memories, then the probabillity that it started 14billion years ago and lead to your existance. Something like that.

[OrbWeaver]

Now that I think about it, the only reference to a "materialising 747" I seem to remember comes from evolution discussions. Refering to the argument that, no matter how often you throw the screws and other material in the air, there will be no 747 coming from it.

 

Yeah, that's one of the cretinists' favourite straw man attacks -- that because evolution is a "totally random process", the chances of mankind emerging fully-formed out of the primordial slime are similar to the chances of a 747 spontaneously assembling itself in a junkyard. Never mind that evolution is NOT a totally random process, and does not say anything about the origin of life in the first place.

[demagogue]

The 747 itself is a red-herring just to dramatize the logic of the point ... so it's not worth focusing on it. Although I did once find a quantum physics course that had as an exam question computing the probability of it happening, with a boatload of simplifying assumptions.

 

Spar had it right with spontaneous particle creation, there is a non-zero probability that virtual particles -- which can spontaneously trigger even from the energy of a total vacuum -- can collapse into "real" (stable, or mostly stable) particles. And get enough of those happening in just the right way, there's supposed to be a probability that it can also put into motion any arbitrary collection of particles as well. (I mean, it's already technically created *this* universe once, from the original singularity subject to these quantum effects, if you want to think about it that way).

But as I said, it's an incredibly esoteric, probability-driven argument.

So it's not really all that serious in the way I was using it, I think.

And, yes, it's quantum effects that are driving all of this (and their non-zero probability of any arbitrary particle creation) ... *not* thermodynamics per se, although quantum effects also have to follow the laws of thermodynamics, so it's incredibly unlikely you'll get spontaneous local entropy increase/organization.

 

One thing, quantum effects get almost totally erased on the classical level of big things. You might see particles spontaneously disappearing and appearing all the time at a very small size, but never at a large size, where pretty much just electromagnatism and gravity run the whole show and keep quantum effects from rearing their weirdo head. So anything about evolution is going to be about just those two forces. I mean, once you've got DNA and transcription and protein creation, you've basically got natural selection up and running, and probably no quantum effects ever being relevant.

 

I'm not a physicist, either. I studied a lot of logic and probability stuff ... from studying metaphysics (*not* the new-age b.s. metaphysics, but the really logic/math based). So I had to learn just enough of the logic of relativity and quantum physics to deal with the questions we were asking, what is space/time, is quantum physics logically sound? Stuff like that. I actually love it when someone with a greater scientific background clarifies things for me, though. So what I just wrote is just my understanding of things I've read ... but I'd be happy to hear what's accurate and not accurate about it.

Edited May 31, 2007 by demagogue

[OrbWeaver]

I mean, once you've got DNA and transcription and protein creation, you've basically got natural selection up and running, and probably no quantum effects ever being relevant.

 

Not exactly -- natural selection arises due to competition between individuals for a scarce resource (food, water, shelter from predators etc). DNA gives you mutation and heredity, which are the OTHER two factors needed for evolution.

[demagogue]

Yes, of course. I should have added "... as far as the necessary conditions go from the organism's internal perspective" (competition, scarce resources, etc, are external factors). But what you say is totally right; what I said is necessary but not sufficient.

 

By the way, the other conditions you just listed are also handled under very conventional classic physics, so my basic point is the same. I guess I've been on this train of thought lately ... the more and more I read, the more it impresses me how really basic elements -- basically electromagnatism and gravity, and the material conditions earth gives us, the soil/water composition, the carbon cycle, energy cycle, water cycle, etc -- all working together to create everything we see around us, life, evolution, minds, language, society, culture ... There really isn't a point where things break-down and you can't explain it with these basic ideas so you have to resort to weirdo metaphysics to cover it. Even some of the more exotic but very real physics (the unstable particles/cosmic rays, quantum effects, black holes) aren't really adding much to the basic picture just from what I mentioned above, in my understanding.

 

I mean, it's one thing to have that idea as something intuitive, like a commitment to naturalism, but it's something more to actually see how it fits together. That's why I've been like Spar lately, really interested in learning about not just relativity, and quantum physics (and brushing up on electromagnatism) but also genetics/microbiology, neurophysiology, computational linguistics/AI, and microeconomics/game theory (and maybe political economy), those 6 or 8 in particular. I feel like when I went to college, I wasn't left with a clear picture of how all the pieces fit together. I just had a lot of the details thrown at me. But suddenly recently (I guess because the internet makes it all so handy to get ahold of) I've felt this drive to fill in the gaps in my understanding, at the very least with place-fillers so I have a name and the basic idea for how X works, from the most basic elements all the way up to the big picture.

Edited May 31, 2007 by demagogue

[OrbWeaver]

Yes, of course. I should have added "... as far as the necessary conditions go from the organism's internal perspective" (competition, scarce resources, etc, are external factors). But what you say is totally right; what I said is necessary but not sufficient.

 

What you said is necessary for Darwinian evolution, yes, but not for natural selection alone. Natural selection could take place if organisms were hand-assembled by gnomes from a specification engraved on a block of cheese.

 

I'm nitpicking probably, but people tend to use the terms "natural selection" and "evolution" interchangeably, when they do in fact refer to different things.

[demagogue]

Right. I'm being incredibly lazy in my terms, but my humble point that began the whole thing wasn't really impressive enough to deserve the critical scrutiny to begin with.

You can be commended for keeping me honest, though.

 

Edit: Actually, though, I pretty much meant to be just talking about Darwinian evolution from the beginning, anyway ... that's the one I care about. So you can read it as "necessary (but not sufficient) elements for natural selection in Darwinian evolution".

Edited May 31, 2007 by demagogue