Has quantum physics disproved determinism? Was Einstein wrong when he said God does not play dice with the universe? - by Steve Baker - Quora Question Review

This document contains a review of the answer by Steve Baker on the question in Quora: "Has quantum physics disproved determinism? Was Einstein wrong when he said God does not play dice with the universe?"
To order to read all the answers select: https://www.quora.com/Has-quantum-physics-disproved-determinism-Was-Einstein-wrong-when-he-said-God-does-not-play-dice-with-the-universe-1

• The text in italics is copied from the article.
  
• Immediate followed by some comments
  

Contents

• 1. Answer Review

Reflection

• Reflection 1 - Question Review
• Reflection 2 - Answer Review

1. Answer Review

Not at all. It simply moved determinism to the wavefunction.

This sentence is difficult to understand. Here the word determinism is simply replaced by the word wavefunction, which is of no much help.

The evolution of the wavefunction is entirely deterministic.

This sentence is not clear. What does it realy tells us?

In fact, the entire field of quantum computing is based on this.

Sorry, but this sentence is empty.

What quantum physics removes is something more nebulous, and that is local realism.

That leads to the conclusion that all concepts determinism, wavefunction and local realism are not clear.

This is where Einstein was wrong, as he was a firm advocate of local realism.

How can Einstein be right or wrong when the concept "local realism" is nebulous. (Any way local realism is not the question.)

This underlying determinism is effectively a statement of causality. It means that every effect has a prior cause.

This statement, by itself, does not say much.

This causal chain of events is referred to as the principle of unitarity.

It ultimately is a conservation law for information; information cannot be created or destroyed.

In general (My definition) any chemical reaction is a conversion between different products. That means certain products are converted into other products. The first are eliminated and the second are created. You could also claim the first are destroyed and the second are created.
In many cases chemical reactions can also 'flow' in opposite direction. That means nothing is destroyed.
In the case when you burn a painting, the original is destroyed and the opposite direction is physical not possible.

This has led to the black hole information paradox, where black holes seem to destroy information.

When a comet collides with the Sun, the whole comet merges with the Sun, and becomes an integral part of the Sun. This process can not be reversed.
Exactly the same happens when a star collides with the Sun.
These are all normal physical processes and have nothing to do with the abstract concept of information.

This is an ongoing field of research that is strongly guided by the principle of unitarity.

The part of quantum theory that is not deterministic is that of the measurement.

At the scale of elementary particles, all measurements are difficult and not accurate.

This forms part of the “measurement problem”, as measurements are not a purely physical process.

All measurements are physical processes.

Until the measurement problem is resolved, the probabilistic nature of measurement outcomes cannot be used as a proof of fundamental stochasticity.

Recently, there has been a theory that has merged classical gravity with quantum theory.

This theory requires that there be a fundamental stochastic element to gravity.

What does "a fundamental stochastic element" mean?

Furthermore, the theory is testable.

How?

If the predictions of this theory are observed, then indeed we would have a fundamental stochastic element underlying reality. However, this is not standard quantum theory. This is a radical extension, and subject to ongoing investigation.

This raises many questions and concerns.

The bottom line is that standard quantum theory considers the deterministic evolution of the quantum state. It is only the process of measurement that introduces indeterminism. Until the measurement problem is resolved, this measurement-induced indeterminism cannot be used to prove fundamental indeterminism.

As already mentioned all measurements with elementary particles are not accurate.
This has nothing to do with determinism versus indeterminism.

Afterall, the principle of determinism is otherwise known as the principle of causality. There is nothing in the theory that gives rise to an effect without a cause.

Not clear.

3.

Reflection 2 - Answer Review

Quora digest is a platform where some one raises a question and some one else gives an answers.
In this particular case the question contains the concepts: Einstein, quantum physics, determinism and God does not play dice
The answer contains the concepts: determinism, wavefunction, quantum computing, local realism, causality, proir cause, unitary, measurement problem, probablistic nature, stochasticity, classical gravity, standard quantum theory, inderterminism and effect.
The question is why do we need all these concepts to answer the original question? What makes this whole exercise so difficult is that many of the concepts used are not clear, which results that the complete answer is not clear.

1. The question discussed has to do with the physical nature of the universe.
When you consider the universe in its totality it is empty space (considered from the human point of view) filled with small objects in the form of dust, standard objects in the form of planets and stars and large objects in the form of blackholes. We humans cannot directly see blackholes but we can deduct their existance based the behaviour of the planets in their surroundings.
One of the most important planet, on which we live, is called: Earth. What we humans can observe is that the physical state of the Earth is constantly changing.
What we humans can also observe that the position of all the planets and stars (at least in our neighbourhood) is also constantly changing.
It is a chalenge of mankind, is to try to understand these changes and to predict these positions in the future.
Let us try to go in more detail.

2. As mentioned the universe consists of a collection of planets and stars. The position of these objects is constantly changing. The point is that at every moment all these objects, throughout the entire universe, have a specif position. And it are these positions we want to know.
At a moment later, again we want to know all the positions of the same objects. And this again and again. Using these positions based on the past, we now want to predict the positions of the same objects in the future. The problem is, that this is more difficult as expected.
A step in the right direction is to collect the positions of the planets and stars at regular intervals. That is correct. But still there exist a huge problem and that is that the positions we observe (from Earth) are not the actual positions at each interval. The reason is because it takes time for actual position to travel to our position. That means what we at each moment see (at regular intervals) are positions in the past.
To be more specific, how far in the past depends about the actual distance between the star and earth, divided by the speed of light. What this teaches us that its difficult to measure the positions of objects acurate at regular intervals and to predict the future.

3. Next let us go deeper in the physics to understand the Universe, including the movement of the star and why there are planets around the Sun.. But first a small intermezzo. In the above we discused what humans have to do to predict the future positions of the stars. In fact that is what astronomers do using telescopes. They use light emitted by the stars in order to calculate positions. But, and this is important, the actual movement of the stars have nothing to do with light. This has nothing to do with the chemical reactions within stars and planets, which can generate heat and emit light.
To go a step futher, the movement of the stars and planets also have nothing to do with the concept time. That does not mean that at earth we cannot have something called seasons and that the average temperature coincides with these seasons, but these seasons don't infleunce the movements of the planets and stars.
This ends this Intermezzo.

4. After this intermezzo, we continue with the physical understanding of the Universe, using our starting point that at any moment the whole Universe is chamging. The simplest Universe we can imagine is a Universe which consists one object: Our Earth. However from physical point of view such a Universe is not interesting, so it stops. The next Universe is a Universe with consists ot two objects. Our Earth and a rock. Initial state is that rock lies on the Earth. With this rock we can do the folling experiment:
1) Lift a stone in the air. 2) Let go of the stone 3) The stone falls down 4) Collides with the ground 5) and stays put How do you explain this experiment? Some people explain this experiment as a thought experiment. The point is that if you are only familiar with the iniside of an empty room, and you have never ever seen anything else how do you know when I take something out of my pocket, lett it loose, that it will actual move down? It could also rise? My understanding is that you cannot predict what is happening, only by using your mind. The only strategy is by performing experiments.
The only way to explain this is by introducing the concepts of a force and energy and that there are similar processes which involve in the same way. In this case the force of gravity.
When you have introduced the concept of force, the next step is to claim that all objects are influenced by such a force, which we call the force of gravity, but a true explanation why this is the case does not exist.
5. The next Universe is a Universe which consists of two objects which revolve around each other. However in reality to study this situation you need a third object which we call Obsever.
In such a Universe there are more or less two confugurations: One object clearly moves around the other object (in a circle), which does not seem to move, or both objects move around each other and a round a common point.
What the observer sees in the first case is that the size of the object in the center is much larger than the object which moves around. In the second example both objects have an almost equal size.
To create the first case you need a large and a small object. If you place them on a horizontal line and you don't do anything else they will collide. If you want to prevent that to happen you should apply an instantaneous force (in a vertical direction) on the small object, and if this the right force the small one will rotate around the large one in a circle. If not the trajectory will be an ellipse. To create the second case you need two objects of the same size. If you place them on a horizontal line and you don't do anything else they will collide. If you want to prevent that to happen you should apply the same instantaneous force (in a vertical direction) on each of the two objects, and if this the right force the small one will rotate around the large one in a circle. If not the trajectory will be an ellipse.
6) The next Universe consists of 3 objects. This is the first realistic concept. To create this universe at a certain moment, you need three objects and each of these objects must have a certain speed. The question is: Is this a stable configuration?
A different question is: How does this universe evolve, or what will be the next position of each object. To anwer this question we must first agree on a number of basic concepts. The first concept must be that the evolution of the universe must go to a sequence of time steps. At every step all the objects in the universe must have a certain position. As a consequence starting from the present, all the objects must have a position in the past and will have one in the future. The consequence is, comparing the present and previous time step, that speed at present of each object is equal to the difference between the positions at the present time step and the previous time step. At the next time step the the speed will be the same adjusted with the gravitational force caused (introduced) by all the other objects, originating from positions of these objects in the past. The past, is the distance between the point considered i.e. influenced and the position of the cause divided by the speed of gravity. All the other objects meaning in general all the other objects in the universe, or more specific in our galaxy or in the solar system.
It is also important that the concept of time steps is important for all the objects considered. The positions at each time step, of all the objects are simultaneous events.
It is also important that in principle the speed of light does not play any role in the physical behaviour of the stars.
However in order to calculate the force of gravity you need observations of the positions in the past and these observations require the speed of light. With the same observations you can also calculate the seize of each object or if you want its mass.
7) If you want to summarize this discussion than the central issue is the force of gravity which causes that all objects in the universe attract each other and assuming that all the objects have a certain speed than this collection of moving physical objects can exist for a long time. The fact that some are invissible (black holes) is of no importance.
Knowing the exact position is of no importance to understand the behaviour of the stars. The same can be said for the elementary particles, electrons, protons and neutrons which are the building blocks.
The point is, that if you want to quantify this behaviour and predict the future than this a whole different issue and very tricky, because then you must know in principle the position of all the objects and the shapes of all the objects in the universe simultaneous. This same problem is also available at elementary particle level which makes accurate predictions impossible.
What is even more any discussion, if the universe is deterministic or indeterministic, in this context, is rather academical.
8) A whole seperate issue in understanding the universe is the the use of mathematics and Laws. Laws are descriptions of the behaviour of objects in a mathematical notation. What is important is the reasoning behind these laws. If these laws introduce new mathematical concepts the road to clear understanding becomes longer. This reflects the general impression of the answer.

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