Big Bang

[Gawdzilla Sama]

You lost me at "Any..."

[Jehanne]

Hi Polymath,

We've been through this before:

http://www.preposterousuniverse.com/blog...-equation/

QFT did not "replace" QM.

But, as your link shows, the Schrodinger equation needed to go beyond the single particle non-relativistic equation is different than the one in Griffiths. In fact, the appropriate equation is usually derived from the Lagrangian formulation and can be put into the Schrodinger form, but the standard Schrodinger equation is the non-relativistic version of things (although it can be multi-particle---which the one in Griffiths is not).

Is not this the Quantum Eternity Theorem that Professor Sean Carroll is speaking of, or, at least a simplified version of it?  I admit that I am no expert, but as I read Professor Griffiths, the central concept is one of renormalization, which, as you seem to acknowledge, implies that the Cosmos is eternal, that is, without beginning or end.

In any case, even if I am reading things wrong here, there are still eternal models of cosmology (infinite universes, in space and time), in the peer-reviewed scientific literature.

---

That the Earth is curved is an absolute fact.  Ditto for the expansion of the Universe.

Quantify “absolute”.

A foundational fact of reality; if not true, then Last Thursdayism is a viable hypothesis.

[polymath257]

But, as your link shows, the Schrodinger equation needed to go beyond the single particle non-relativistic equation is different than the one in Griffiths. In fact, the appropriate equation is usually derived from the Lagrangian formulation and can be put into the Schrodinger form, but the standard Schrodinger equation is the non-relativistic version of things (although it can be multi-particle---which the one in Griffiths is not).

Is not this the Quantum Eternity Theorem that Professor Sean Carroll is speaking of, or, at least a simplified version of it?  I admit that I am no expert, but as I read Professor Griffiths, the central concept is one of renormalization, which, as you seem to acknowledge, implies that the Cosmos is eternal, that is, without beginning or end.

In any case, even if I am reading things wrong here, there are still eternal models of cosmology (infinite universes, in space and time), in the peer-reviewed scientific literature.

---

Well, even the derivation given only shows that the probability is constant through time. If time itself is finite, then the proof just applies when there is time.
But yes, there are models where time is not finite.
Which is why we just don't know which option is correct. At this point there simply isn't the data to choose between theories with finite time and those with infinite time.

[Anomalocaris]

But, as your link shows, the Schrodinger equation needed to go beyond the single particle non-relativistic equation is different than the one in Griffiths. In fact, the appropriate equation is usually derived from the Lagrangian formulation and can be put into the Schrodinger form, but the standard Schrodinger equation is the non-relativistic version of things (although it can be multi-particle---which the one in Griffiths is not).

Is not this the Quantum Eternity Theorem that Professor Sean Carroll is speaking of, or, at least a simplified version of it?  I admit that I am no expert, but as I read Professor Griffiths, the central concept is one of renormalization, which, as you seem to acknowledge, implies that the Cosmos is eternal, that is, without beginning or end.

In any case, even if I am reading things wrong here, there are still eternal models of cosmology (infinite universes, in space and time), in the peer-reviewed scientific literature.

---

Quantify “absolute”.

A foundational fact of reality; if not true, then Last Thursdayism is a viable hypothesis.

As you enumerates our current understanding of reality, what criteria do you use to assess which of what we believe to be facts are foundational, and which are not?

It seems to me Last Thursdayism is, and very likely will always remain, a viable hypothesis. it is just an as yet unsupported hypothesis. The possibility of it being true, while likely extremely small, certainly isn’t zero.

[Jehanne]

Is not this the Quantum Eternity Theorem that Professor Sean Carroll is speaking of, or, at least a simplified version of it?  I admit that I am no expert, but as I read Professor Griffiths, the central concept is one of renormalization, which, as you seem to acknowledge, implies that the Cosmos is eternal, that is, without beginning or end.

In any case, even if I am reading things wrong here, there are still eternal models of cosmology (infinite universes, in space and time), in the peer-reviewed scientific literature.

---

Well, even the derivation given only shows that the probability is constant through time. If time itself is finite, then the proof just applies when there is time.
But yes, there are models where time is not finite.
Which is why we just don't know which option is correct. At this point there simply isn't the data to choose between theories with finite time and those with infinite time.

The only thing that I am claiming is that there are plausible, naturalistic models that explain why there is something rather than "nothing", namely, that the Cosmos has always existed.

---

Is not this the Quantum Eternity Theorem that Professor Sean Carroll is speaking of, or, at least a simplified version of it?  I admit that I am no expert, but as I read Professor Griffiths, the central concept is one of renormalization, which, as you seem to acknowledge, implies that the Cosmos is eternal, that is, without beginning or end.

In any case, even if I am reading things wrong here, there are still eternal models of cosmology (infinite universes, in space and time), in the peer-reviewed scientific literature.

---

A foundational fact of reality; if not true, then Last Thursdayism is a viable hypothesis.

As you enumerates our current understanding of reality, what criteria do you use to assess which of what we believe to be facts are foundational, and which are not?

It seems to me Last Thursdayism is, and very likely will always remain, a viable hypothesis. it is just an as yet unsupported hypothesis. The possibility of it being true, while likely extremely small, certainly isn’t zero.

No hypothesis has a probability of zero; but unlike modern geophysics, Last Thursdayism, as a hypothesis, is not productive; it makes no predictions and leads to no testable experiments with measurable outcomes. As with all religious beliefs, it is one idea from an infinite set that can be chosen from.

[Rahn127]

First we start with accepting that the universe exists here and now.

If you examine the energy of the universe and see how it has changed, you come to realize that all it does and all it ever has done is change.

At no point does it ever not exist.

[Jehanne]

First we start with accepting that the universe exists here and now.

If you examine the energy of the universe and see how it has changed, you come to realize that all it does and all it ever has done is change.

At no point does it ever not exist.

The Heisenberg Uncertainty Principle also implies that "norhingness" is a state of physical impossibility. The physicist Edward Tryon explored this possibility nearly 50 years ago.