Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum A Single Universe or a Multiverse?

Ibliss: "Hello Pasti, I had some problems posting here (I could no longer login and had to register again)."

Send an email to Kate, she should be able to fix this problem.

Ibliss: "I have no hidden agenda."

I am more than happy to hear this. So let's continue the discussion.

Ibliss: "My agenda is nothing more than trying to show that the notion of a physical universe is flawed (like the notion of a God)."

Why would you need that?Why does the existence of the concept of physical reality bother you so much? Alternatively, why does the principles of general covariance/invariance bother you? You consider them incorrect?


Ibliss: "I don't see how information is created according to any of the known or proposed laws of physics. Hawking radiation wouldn't have been a big deal if physicists really believed this."

Let me see. I just destroyed 25 of the 50 pages I wrote for my paper,so I created info, and I destroyed some, and the net balance is that I actually created info.

As for the Hawking radiation, do net get too excited, since in the context of information creation/annihilation the BH is not a very relavant example, in the sense that the system is much too simple, and does not reflect the overall physical reality (see above childish example). If I look to the attempts made today in the context of quantum gravity to characterize information contained in the horizon of the black hole, it reminds me of the Fall of the Constantinopole, when with the turks at their gates the church could find nothing better to do that debate hom many angels can exist on the tip of a needle!

Ibliss: "No experiment has ever observed a nonunitary time evolution of an isolated system."

Once again, the systems investigated are rather simple, and isolated systems are in truth only abstractions. I think calorimetry illustrates this point very well.

Ibliss: "I still have to look up the articles by Lloyd. I don't know enough about Quantum Cosmology to say that Penrose's models are realistic."

Well, for the Penrose ideeas, if you want I can dig up some refs. It is called combinatorial quantization, and sme people, Penrose included are or have been very excited about it.

Ibliss: "However, let's not forget that in mathematics only systems that use first order logic are 100% well defined."

I am not familiar with what first order logic means, but since when are all physical systems well defined? Think of QED and renormalization.

Ibliss: "It is more convenient in practice to use higher order logical systems, but one cannot argue that just because we use, say, the uncountable reals, that space-time is necessarily uncountable. A trivial counterexample:In principle, I could have simulated a physicists making this assertion inside a finite state machine!"

I agree with you, regarding the countability argument. But on the other hand one cannot impose countability as a principle just because for a few simple models indeed the quantization is purely combinatorial.


Ibliss: "I didn't understand this comment:''You cannot eliminate the question of what is physical reality, because then you loose the consistency of description. In other words, everyone becomes a mental case with his own perception, no matter what the perception of others is.''."

What I wanted to say is the fact that physics is the slave of a higher authority, so to speak, namely observation. Observation that is defined, if you whish, to be reproducible regardless of the observer, i.e. in the same experimental conditions both you and I, in different labs should observe the same, say, ionization potential of the H atom.
Physical reality is defined, generally speaking, as the set of all hierarchies of observable phenomena, even if some observations have not been performed yet.
The models describing this physical reality are a different issue, but the most fundamental characteristic of a model is consistency with the physical reality as defined above (note that some models might be incomplete, or consistent at one level and inconsistent at others, etc.) If you eliminate the physical reality, we could end up as Asimov said in one of his books:we could both look at a basaltic stone, and you could claim it is basalt while I can claim with equal value of truth(in my own physical reality) that it is actually a ruby stone. This is the "mental case" trend I was talking about. Which in the best case leads to mysticism, but not to science.

Ibliss: "The world in which we live would simply be purely mathematical in nature. It doesn't mean that I cannot do physics anymore."

How could it be so? Mathematics is a purely abstract system, which needs input from the physical world. First you have to do "physics", and then math.

Ibliss: "What is true is that the question of why the scientific method works becomes relevant and now has to be explained (maybe that is what you meant)."

You have lost me here. Of course it works, because the consistency requirement mentioned above acts as feedback in the evolution/development of a model/understanding.

Ibliss: "I don't see this. There is no reason why today the universe works according to the same laws as yesterday. You have to postulate the existence of fundamental laws first."

No, I do not have to postulate anything, truth be told. I only need to do observations, find patterns and trends, and after verification, memorize them and apply them until I find observations that deviate from or invalidate these trends. At which point I rethink the trends, and the cycle continues as before.

Ibliss: "You cannot invoke the AP, because our existence is compatible with, say, changing the masses of electrons by tiny but measurable amounts."

No,I cannot, you are right. But for the time being I have too litle information/knowledge to actually make such a connection. And the anthropic principle is nothing more than a trick, if you like, that covers this lack of knowledge.

Ibliss: "Note that I want to explain the observation of physical reality that these things do not happen. Saying that it doesn't because we don't observe it doesn't explain it. Newton could have said that apples fall toward the ground because he opbserved it. True, but that doesn't explain his observation."

Well, I agree with you here, observation does not mean explanation. But the consistency requirement mentioned above will at certain points (when and if enough info/knowledge becomes available)lead you to the explanation, as it has happened before.

Ibliss: "Similarly, I want to know why the scientific method works."

I guess the above "feedback" explanation would be a good starting point for such a discussion.