Comments about "Philosophy of space and time" in Wikipedia

This document contains comments about the article Philosophy of space and time in Wikipedia
In the last paragraph I explain my own opinion.

Contents

Reflection

Introduction

The article starts with the following sentence.
The subject focuses on a number of basic issues, including whether time and space exist independently of the mind, whether they exist independently of one another, what accounts for time's apparently unidirectional flow, whether times other than the present moment exist, and questions about the nature of identity (particularly the nature of identity over time).
Space, the fact that there is a 3D world, and that space exists in time have nothing to do with we humans.
Space and time are one undivisible entity. You cannot have one without the other.

1. Ancient and medieval views

Aristotle, in Book IV of his Physics, defined time as the number of changes with respect to before and after, and the place of an object as the innermost motionless boundary of that which surrounds it.
That is a very clever definition.
Time is a concept related to the mind of a human being. Time defines related to any event what happened before and after that event.
Space defines al what surrounds any object and is not part of any object.

2 Realism and anti-realism

A traditional realist position in ontology is that time and space have existence apart from the human mind.
Correct.
Some anti-realists, whose ontological position is that objects outside the mind do exist, nevertheless doubt the independent existence of time and space.
The last is correct because what exists are objects and this existance implies that they exist in time.
Some idealist writers, such as J. M. E. McTaggart in The Unreality of Time, have argued that time is an illusion (see also The flow of time, below).
This completely depents about the definition of what is an illusion and what is time.
See also: Reflection 1 - The philosophy of space and time

3. Absolutism and relationalism

The great debate between defining notions of space and time as real objects themselves (absolute), or mere orderings upon actual objects (relational), began between physicists Isaac Newton (via his spokesman, Samuel Clarke) and Gottfried Leibniz in the papers of the Leibniz–Clarke correspondence.
It is wrong to call both space and time both objects. Again starting point should be proper definitions of both.
Also the use of the word absolute requires a proper defintion.
Arguing against the absolutist position, Leibniz offers a number of thought experiments with the purpose of showing that there is contradiction in assuming the existence of facts such as absolute location and velocity.
It is extremely difficult to study these physical concepts based on thought experiments
The identity of indiscernibles states that if there is no way of telling two entities apart, then they are one and the same thing.
Space and time are not one and the thing, they are different parameters of every object in space. Each object has three size directions and one time component.
The example Leibniz uses involves two proposed universes situated in absolute space.

3.1 Leibniz and Newton

The great debate between defining notions of space and time as real objects themselves (absolute), or mere orderings upon actual objects (relational), began between physicists Isaac Newton (via his spokesman, Samuel Clarke) and Gottfried Leibniz in the papers of the Leibniz–Clarke correspondence.
In any case the notions of space and time are not objects. Space itself is physical completely empty.
Arguing against the absolutist position, Leibniz offers a number of thought experiments with the purpose of showing that there is contradiction in assuming the existence of facts such as absolute location and velocity.
Thought experiments can never solve this issue.
The easiest solution is to delete the word absolute. It adds nothing in this sentence.
The principle of sufficient reason holds that for every fact, there is a reason that is sufficient to explain what and why it is the way it is and not otherwise.
The principle of sufficient is not clear. What means: "what and why it is"?
The identity of indiscernibles states that if there is no way of telling two entities apart, then they are one and the same thing.
What means: "of telling two entities apart"? The issue that in principle the concept of space is not very helpfull. It is closely related to the concept: universe.
What is important is that space is not empty but filled with objects. For these objects the concept of time is important.
The example Leibniz uses involves two proposed universes situated in absolute space.
Maybe in the mind of Leibniz it is clear what he means with two universes in absolute space, but that is definitily not the case with the readers. Not all the readers will have the same understanding.
The only discernible difference between them is that the latter is positioned five feet to the left of the first.
Also this may be clear for Leibniz, but again definitely not for all readers.
The example is only possible if such a thing as absolute space exists.
How do you know that it is possible that you can have five feet appart?
Such a situation, however, is not possible, according to Leibniz, for if it were, a universe's position in absolute space would have no sufficient reason, as it might very well have been anywhere else.
What Leibniz discusses are two problems or issues with both are not clear.
This is a very nice example about what is written here: Reflection 2 - Solving problems which are not clear or maybe do not exist.
The general problem is that all therminology used should be clear.
Standing out in Clarke's (and Newton's) response to Leibniz's arguments is the bucket argument: Water in a bucket, hung from a rope and set to spin, will start with a flat surface. As the water begins to spin in the bucket, the surface of the water will become concave. If the bucket is stopped, the water will continue to spin, and while the spin continues, the surface will remain concave.
The real experiment is much more complex as this description: The bucket does not start to spin by itself.
In this response, Clarke argues for the necessity of the existence of absolute space to account for phenomena like rotation and acceleration that cannot be accounted for on a purely relationalist account.
The real argumentation must have been different. First you should explain what absolute space means.
Clarke argues that since the curvature of the water occurs in the rotating bucket as well as in the stationary bucket containing spinning water, it can only be explained by stating that the water is rotating in relation to the presence of some third thing—absolute space.
This line of reasoning makes more sense, but that does not mean that the concept "absolute space" makes sense.

3.2 Mach

While he did not deny the existence of phenomena like that seen in the bucket argument, he still denied the absolutist conclusion by offering a different answer as to what the bucket was rotating in relation to: the fixed stars.
What physical means: fixed stars.
Mach suggested that thought experiments like the bucket argument are problematic.
That is correct. Thought experiments have the tendency to become to simple explanation or experiment. To perform the experiments in real is much more complex.
If we were to imagine a universe that only contains a bucket, on Newton's account, this bucket could be set to spin relative to absolute space, and the water it contained would form the characteristic concave surface.
You can imagine a bucket in empty space, but how do you imagine that this bucket starts to spin? How do you know that the bucket spins?
The same problem more or less also exists when you study the Foucault's pendulum. https://en.wikipedia.org/wiki/Foucault%27s_Pendulum

3.3 Einstein

4 Conventionalism

5 Structure of space-time

Building from a mix of insights from the historical debates of absolutism and conventionalism as well as reflecting on the import of the technical apparatus of the General Theory of Relativity, details as to the structure of space-time have made up a large proportion of discussion within the philosophy of space and time, as well as the philosophy of physics.
My understanding is, that the concept of space-time does not recognizes the two concepts space and time.
My understanding is, that the concept of space-time is a mathematical concept.
My understanding is, that the concepts space and time is a physical discussion. To measure time requires a clock.
Before you want to discuss space-time in more detail you must first now what space-time means. In some sense you need experiments to demonstrate what it is.

5.1 Relativity of simultaneity

According to special relativity each point in the universe can have a different set of events that compose its present instant.
This sentence is not clear.
This has been used in the Rietdijk–Putnam argument to demonstrate that relativity predicts a block universe in which events are fixed in four dimensions.
As a result this sentence is also not clear.

5.2 Invariance vs. covariance

5.3 Historical frameworks

5.4 Holes

6 Direction of time

The problem of the direction of time arises directly from two contradictory facts.
That is may be the simplest reason why it is wrong.
Firstly, the fundamental physical laws are time-reversal invariant; if a cinematographic film were taken of any process describable by means of the aforementioned laws and then played backwards, it would still portray a physically possible process.
The problem with the laws of physics is that they describe never the full process but only a part.
Anyway it is not clear which specific aforementioned law or laws are mentioned.

6.1 Causation solution

6.2 Thermodynamics solution

The second major family of solutions to this problem, and by far the one that has generated the most literature, finds the existence of the direction of time as relating to the nature of thermodynamics.
The fact that water flows from high to low and that heat flows towards a place which is cooler has nothing to do with the direction of time.

6.3 Laws solution

A third type of solution to the problem of the direction of time, although much less represented, argues that the laws are not time-reversal symmetric.
This is typical a sentence which tries solve a problem that is not clear and maybe does not exist, therby deepening the problem.
For example, certain processes in quantum mechanics, relating to the weak nuclear force, are not time-reversible, keeping in mind that when dealing with quantum mechanics time-reversibility comprises a more complex definition.
In reality there exist no problem which is time reversible. You can unroll a carpet roll and you can roll up a carpet to a roll, but both processes are completely different.

7 Flow of time

8 Dualities

9 Presentism and eternalism

According to Presentism, time is an ordering of various realities.
The only thing that should considered is the concept now. The concept now recognizes the present state of the whole universe. The concept now also recognizes that there is a future and a past. That means it is based on a one frame concept which includes all. The state of this whole frame is called the reality. As such the evolution of the universe flows through a sequence of realities.
To order these sequence you need one clock.

10 Endurantism and perdurantism

11. See also

Following is a list with "Comments in Wikipedia" about related subjects

Reflection 1 - The philosophy of space and time

The philosophy of space and time does not study the concepts of phase and time directly. Instead it studies what the rules are in order to start both concepts.
One important point is to start with good definitions i.e. what is space and what is time. The problem is both cannot be studied separately because they exist both together. They are concatenated i.e one undivisible total.
What can be studied separately are clocks i.e the behaviour of clocks.
Part of the problem is that space does not exist, because in principle space is empty. What exists are physical objects positioned somewhere in the universe or in space.

Reflection 2 - Solving problems which are not clear or maybe do not exist.

What is reason that the universe is (looks) the same in all directions. That is the question
First of all is the universe the same in all directions?
That is also an important question, because if that is not true it does there is no problem in the first place.
Some times the same question in raised in the slightly different way: What is the reason that the universe is homogeneous and isotropic?
This question is complicated because what means homogeneous and isotropic?
When these two concepts are not clearly defined the problem does not make sense.

It is also very important that early a warning is raised because you know 'everyone' is going to try to solve a problem, as if there is something important to discuss, which is not the case.

This problem is very important concerning the philosophy of science.

Reflection 3

Feedback

If you want to give a comment you can use the following form Comment form
Created: 1 March 2019

Go Back to Wikipedia Comments in Wikipedia documents
Back to my home page Index