If we are living in a simulation does this mean God does not exist?

[stevevw]

Lets look at String Theory as an example of something that is actively promoted, seems to offer support for existing theories such as quantum field theory, yet is considered by many in mainstream science to not even being a scientific theory.

Before tackling this issue one needs to go back to classical physics and debunk the notion expressed in this thread that classical physics is built around “common sense” and “intuitiveness”.
Consider the inverse square law for gravity and electrostatics;

For a spherical distribution of masses m or charges q, the maths can be simplified by considering the mass or charge to be concentrated at a point.
This point particle is dimensionless and takes up no space; it is clearly a mathematical construct and has no physical reality.

When Einstein found the equivalence between mass and energy E = mc², the concept of a point particle became problematic as the field around a point particle also contributed to mass.

The mass of the electromagnetic field mₑₘ is defined as;

For a point particle rₑ → 0 and mₑₘ becomes infinitely large.
While this was not an insurmountable problem in quantum mechanics it became a serious issue in quantum field theory which is the application of special relativity to quantum mechanics.
The problem of infinities cropped up in quantum field theories as in classical physics of treating particles as point sources.
A saving grace in most quantum field theories is the concept of renormalization.
In the case of QED (quantum electrodynamics) when charged particles interact with each other they undergo an oscillation which “smears” the charge over a small region of spacetime.
Since the charge is no longer point like, the small scales less than this region of spacetime can be ignored in the calculations.
The infinities disappear at they only occur at these small scales.

QED is known as a renormalizable theory but unfortunately there is no quantum field theory of gravity which is renormalizable; one cannot get rid of the infinities in the calculations.
This is where String Theory comes into the picture.
It adopts many of the principles of quantum field theory with the major exception of point particles which are replaced by vibrating strings at extremely small scales.
Since these strings have a size, quantum gravity is renormalizable in String Theory and a theory of everything where the forces are unified in the early universe becomes possible using String Theory.

So what is the problem with String Theory?
This link provides an excellent explanation.
Why String Theory Is Not A Scientific Theory

Wow thankyou for your break down, Its a bit over my head though. I agree that String Theory has no scientific verification but it is held up by some as the only possible hope for a theory of everything. I think people relate more to the classical physics as we can see it at work around us at its simplest form. But you lost me at the calculations so maybe you need to explain it in layman terms for me.

 

[sjastro]

Wow thankyou for your break down, Its a bit over my head though. I agree that String Theory has no scientific verification but it is held up by some as the only possible hope for a theory of everything. I think people relate more to the classical physics as we can see it at work around us at its simplest form. But you lost me at the calculations so maybe you need to explain it in layman terms for me.

Quantum field theories involve particle-particle interactions and particle interactions with the field.
The physical process has an initial quantum state |i> and a final quantum state |f> after some time t due to the interaction.

The calculation for the transition |i> → |f> is the probability the transition will occur.
The physical process involves momentum.
In a two particle interaction, initially the particles have a momentum p₁ and p₂; after interaction the momentum is p₃ and p₄.
Momentum is conserved (p₁ + p₂) = (p₃ + p₄).
During the transition |i> → |f>, the momentum changes due to emission and absorption of virtual photons and the momentum carried by the virtual photons.

The calculation involves summing each process where momentum changes occur from which the probability of the transition is determined.

As mentioned in the video where the process involves photons being converted into particle/antiparticle pairs or charged particles interacting with the field and gaining mass, infinities crop up in the calculations that are removed by renormalization.

 

[chilehed]

If we are living in a simulation does this mean God does not exist?

No.