String Theory sounded very promising in the beginning but a lot of people have been working on it for over 30 years and the more work is done the less it seems that it points in the right direction. It's time that somebody starts exploring other paths because String Theory seems to be a dead end, some nice mathematical coincidences and relationships but without any relevance to the physical world.

Sorry for the digression. In all due honesty, I know nothing of The String Theory, but I ain't voting for the "12-string" option.

I actually think it's really important for people to spend time considering something like this as much as they can.  At least to watch something about it and be exposed to it.  It really forces you to evaluate what you're doing.  Broadening your awareness like that breaks you from routine and can put things into perspective.

Here's my answer:

Well, that was quite the original hope, and if proved true (even if only meaning 'mathematically consistent complete theory') it would have provided a very powerful unifying principle and a conceptually attractive explanation for why do we see so many different 'elementary' particles and forces in the Standard Model (plus hopefully also the ones we do not really know such as dark matter).

Pity is, that after years of work the dream of such great underlying simplicity did not hold up. It became clear that 'vibrating strings' could not explain the whole edifice and other concepts needed to be gradually added, first closed loop strings, then, 2-branes, D-branes, p-branes... Of course the theory may still be right but the edifice being assembled in String Theory is again so complex that the initial motivation of conceptual simplicity has been lost. The main problem in String Theory though, is that it seems to allow a potentially infinite diversity of possible universes and offers no clue as why our universe is as it is. Saying that anything is possible so consequently our universe must be one of the infinite possibilities is not a very helpful solution to our desire for understanding.

Exactly. It's fun to think about these things and consider the possibilities, but in the end we won't really find a meaning or a goal or completely understand the universe. I actually believe it's very improbable that the actual structure of the universe is within the reach of the human understanding.

That may well be right, but it should not stop us from trying. Just trying is a very rewarding exercise, we have made decent progress so far so we must certainly keep trying.

I am actually cautiously respectful of John Wheeler's philosophy which roughly states that the 'purpose of life' is to understand (or rather, 'to make real' or 'make happen') the universe ('the participatory universe principle'), or those who propose that 'consciousness' eventually will evolve to encompass all the knowledge required to understand the universe, effectively making a loop where 'understanding' or 'awareness' and 'physical reality' are just two sides of the same coin.

Sorry, a bit profound for a Prog Rock forum probably 

Might be, but then again I think one could doubt to what point this is still 'understanding' and where it turns into 'believing'. For example, many religious people think their religion already explains all there is to know about the universe. In that case, you might be 'done' by taking on a religion.

mmmmmmmmmmm

I believe in a) preferably what I can understand, or otherwise at least in b) what I can perceive as 'objectively true' even if I don't understand it (take quantum mechanics).

No religion has offered me any of these perceptions so far.

 

 

 

Consciousness too.

I personally think that String Theory is not really on the right track but who am I to tell...  At any rate it provides some useful principles and concepts and could have some bearing to the actual truth, some of its mathematical 'coincidences' are possibly too striking to be 'just coincidences'. I think we are still rather far for any true understanding of what's really going on, but keeping on trying is great and we should not give up.

A recurring problem in this sort of things is that mathematics has proved to be extremely fertile, there are lots of mathematical facts which are amazing and clearly true but which in principle do not seem to have any bearing at all with the actual physical world. String Theory is possibly a bit on the same path, it builds on some mathematical structures and relationships, but whether it has any significance to the actual physical world in rather unclear.

We expect our universe to behave in a mathematically consistent way, but that does not mean that any mathematically consistent structure is actually deployed by nature in our real universe. We may find lots of mathematically consistent structures which have no physical implementation in our actual universe. And I feel that String Theory is one of these.

Sorry, again possibly a bit too profound 

1:03 - 5:30 is the relevant part.

This is an old dilemma, on one side we strive for understanding ever more and we dream with finding a theory of everything, but if we did ever find it, would might that imply? would 'the future unfold in front of our eyes'?, would there still be randomness and unpredictability preventing us from knowing the future?, would it affect our freewill? would the motivation of knowing and understanding fade away, as if 'there's nothing more for us to do'? In a certain sense, while we search for it, we hope to never find it, for the consequences might be scary.

As for the video, honestly I don't hear anything that scientists are not aware of, he's just blablabla trying to sound transcendental, nothing of what the guy says should be any reason for being anti-scientific.

I don't think he's being anti-scientific.  My understanding of what he's saying is that this question is outside the scope of science.  You can't drive your car to the moon.  But you can drive your car to a spaceship and then fly to the moon.

I don't know how far can we drive, nor in how many steps, but let's drive as much as we can and see where do we get to. If you already think that you will hit a wall so it's not worth trying, no good.

Personally I'm also wary of a 'theory of everything', among many other things it's highly doubtful that it would 'explain everything'. Mathematical physics theories as we understand them now are unlikely to be able to explain emergent phenomena such as life, consciousness, chaos, fractals, social behaviour and all other manifestations of emergent complexity, emotions, love...  but we should not give up trying to understand ever more, in some way it may seem that learning about the universe where we live in is the reason why we exist.

At the time of writing that post the name of such a view's proponent didn't come to my mind but I remembered it, for anyone interested it's Frank Tipler's Omega Point hypothesis

http://en.wikipedia.org/wiki/Frank_J._Tipler" rel="nofollow - http://en.wikipedia.org/wiki/Frank_J._Tipler

I thought I had a decent (non-technical) understanding of quantum mechanics until I just listened to a theoretical physicist as a guest on a podcast.  Just as mind-blowing (and incredible that we can know it to be true) as when I first heard about it.

Also amazing, but in a depressing way, most people don't have a clue about any of it.

This is an unforgivable cultural shame. One of the most important (if not the most) milestones in human knowledge and it's basically unknown by most of the population. The same with Relativity (both Special and General), they were discovered 100 yeas ago and yet they are not known (let alone understood) by most normal people... but, sure they know about computer games and Facebook... what kind of world are we living in?

Sure, quantum mechanics and relativity rarely touch our daily lives in direct ways, but the fact that such important rules governing our world are known only by a very small part of the population is sad.

i have then been through everything, biology, zoology, ornithology, anatomy, geography, geology, cosmology, 

but i have also a wide interest in fantastic literature so my taste for philology, mythology, linguistics, symbology, fairy-tales, myth, folklore, theology, humanism, 

String theory intrigues both my scientific part of my brain but also the fantastical part of my brain,  its feeds on both my curiosity and imagination, my hunger for learning more of science but also hunger for fantasy literature, with multiple dimensions. 

 

 

I really recommend you 'Not Even Wrong', it's a kind of reaction to the popular science books about string theory such as Brian Greene's 'The Fabric Of The Cosmos' and such. It's maybe a bit over to the opposite side (against string theory) but very worth the reading if you are smart enough to use the reading to form your own opinion. 

Everything points the other way around though, most physicists believe that General Relativity needs to be quantized. GR does not only describe spacetime but also matter and the way both of them interact, in GR both spacetime and matter / energy are classical (continuous). It is known that matter / energy is quantized, so from this point of view GR is already incorrect. There are some approaches where quantized matter / energy interacts with continuous spacetime but they also present difficulties. Quantum field theory by itself is not devoid of problems either, it is based on a rigid background geometry (that of Special Relativity) when we know that the background geometry is not rigid.

So none of both look like real winners, the solution probably needs to be something else altogether.

a) gravitons

b) 9 dimensions or 11

c) multiverse,

how can you test gravitation in a lab, 

I know that a punch (boxing punch) straight can mac be 150 to 400 kgs or more) a boxing punch down can be between 700 to 1200 kgs, because of the pull of gravity, its easier to hit hard with the help of gravitational pull then, punching straight out in the air with gravitation breaking you kinetic force 

A prediction of sting theory and other attempts at TOE's (Theory Of Everything). Extremely difficult to detect experimentally due to their very weak interaction, but I guess that if the theory proved to be consistent and complete, most physicists would be happy to accept them even without direct experimental detection.

If all the other forces can be described as being mediated by force-carrier particles, it's very tempting to expect that gravity should as well have its force carrier particle.

aginor wrote:   b) 9 dimensions or 11

The lastest versions of string theory (M-theory) have 11. 9 was the prediction of earlier versions of string theory.

aginor wrote:   c) multiverse,

there are two different uses of this term. One is in the context of Many Worlds Interpretation (of quantum mechanics) which represent alternate universes, different versions of our universe in which events happen differently.

The other use is in the context of Eternal Inflation, which states that new universes are continuously born, different from each other, usually referred to as "bubble" universes or "child" universes.

aginor wrote:   how can you test gravitation in a lab,

What do you mean? gravitation is experimentally proven, in lab and out the lab. The Solar system is a big lab.

Possibly the problem comes from trying to describe things in our human everyday language. "Particles" are neither particles nor waves, they are "whatever" and these "whatever" entities depending on the circumstances can display wave-like properties or particle-like properties. They are neither of both, wave or particle are just familiar terms which we can associate with the behaviour we observe from those entities.

Sorry but that doesn't interest me in the least and I'm not going to spend 45 min watching this. If you point me to some precise minute of the doc where they say that I may have a look at it.

Gravity is an extremely weak force and it works noticeably only because of its cummulative property. You routinely overcome the gravitational pull of the whole planet Earth every time you lift a coin from the floor. A simple fridge magnet overcomes easily the gravitational pull of the whole planet.

With objects smaller than a small planet or moon, gravity is rather negligible.

Kinetic energy is gravitational force, and it decides the power of the strikes, your base weight, your acceleration, your speed and strike force is all defined by the laws of gravity, etiolation of gravity. there is over 1000 tests and data and feats which confirms that,    

I won't argue about the strength of gravity, it is indeed a "different" sort of strength, weak in unit power but very long-range reaching and cummulative, so large amounts of mass can exert a very strong total force.

Black holes do have size, that determined by the event horizon. We are not sure what goes on inside the event horizon and we are not sure at all if there is a singularity at the center, GR says that there should be one but this is precisely why most physicists believe that GR is wrong, because they assume that singularities are not physical.

The matter which has fallen into a black hole is definitely still in our universe, we know because we still feel its gravity.

is dark energy force explaining the very big like general relativity or is it describing the small quantum mechanics.

also Hackett, would you join me at the Quantum Club and Cafe    and play some quantum pool or card game.

I'm not sure that Dark Energy has been formally considered as a "force" (I don't think so), although I would say that it could well be a candidate, it can exert work (sending two clumps of matter away from each other overcoming the gravitational attraction between them).

But it does not "explain" anything, it just says that the expansion of spacetime is accelerating.