What multiverse model is this author referring to?

In summary: I think this is more like the 2+2=5 example.In that example, the equation 2+2=5 is always true, but when the equation is applied to apples in the physical world it is open to falsification.If everything in a universe would happen in a random way, then "logic" would not be of much use for the creatures living there.2+2=4 is true by definition of 4.So it would work in every universe possible.And at least one branch of Wittgenstein's philosophy Logical positivism fell out of favor well within the 20th Century particularly after work by Karl Popper, among others. (https
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John's Barrow book "The Constants of Nature" in chapter 13, he talks about a hypothetical multiverse composed of universes governed by other logics. Specifically, he talks about different approaches that physicists take when studying the multiverse, and he mentions a radical approach where even logic could change from one universe to another. But he does not specify any multiverse model...So what is he talking about? Is it there any multiverse model where even the fundamental logic of universes could change?
 
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Not within the three frameworks of physics (MWI, inflation and the string landscape) as far as I know. It seems like wild speculation.
 
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It is popular in cosmology to imagine that there are many possible laws of nature all of which exist in one universe or another to try to explain why our universe is the way that it is, often in conjunction with the anthropic principle.

The problem with this approach is that this is done using Bayesian statistics with an arbitrary "prior" expectation concerning how the possibilities are distributed that has no empirical basis, which makes it purely speculative.

Many critics of this approach are loathe to even call this kind of approach "scientific" but it is used by a fair number of professional trained and employed theoretical physicists.
 
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It is not clear what a universe obeying a "different logic" means. If we observe such a universe from the outside, it will certainly obey our laws of logic. If we watch a movie about a mental institution, the logic of the inpatients may be broken, but our own logic does work.

Ludwig Wittgenstein pondered if 2 + 2 = 4 is an empirical fact or somehow dictated by logic. We may imagine a universe where every internal observer at every experiment would observe 2 + 2 = 5. Then one might say that the universe obeys a "different logic", for the observers living inside that universe.

If everything in a universe would happen in a random way, then "logic" would not be of much use for the creatures living there.
 
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Heikki Tuuri said:
It is not clear what a universe obeying a "different logic" means. If we observe such a universe from the outside, it will certainly obey our laws of logic. If we watch a movie about a mental institution, the logic of the inpatients may be broken, but our own logic does work.

Ludwig Wittgenstein pondered if 2 + 2 = 4 is an empirical fact or somehow dictated by logic. We may imagine a universe where every internal observer at every experiment would observe 2 + 2 = 5. Then one might say that the universe obeys a "different logic", for the observers living inside that universe.

If everything in a universe would happen in a random way, then "logic" would not be of much use for the creatures living there.
2+2=4 is true by definition of 4.
So it would work in every universe possible.
 
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And at least one branch of Wittgenstein's philosophy Logical positivism fell out of favor well within the 20th Century particularly after work by Karl Popper, among others. (https://en.wikipedia.org/wiki/Karl_Popper#Philosophy_of_science).

Popper's approach to the statement 2+2=4 appears simple but may offer guidance to understanding the implications of the original post.
Popper's solution[45] was an original contribution in the philosophy of mathematics. His idea was that a number statement such as "2 apples + 2 apples = 4 apples" can be taken in two senses. In one sense it is irrefutable and logically true, in the second sense it is factually true and falsifiable. Concisely, the pure mathematics "2 + 2 = 4" is always true, but, when the formula is applied to real-world apples, it is open to falsification.
 
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Klystron, exactly. If I put 2 + 2 apples in a bag and always can count 5 apples when I empty a bag, then I conclude that 2 + 2 = 5 in the physical world. We can imagine a universe where every observer at every situation will count 2 + 2 = 5.

An outside observer may see that the observers living in that universe always make a counting error. Or he may see that apples materialize from nothing. For the outside observer, 2 + 2 = 4, but internal observers will find the rule 2 + 2 = 5 more useful.

One may claim that the rules of logic are an empirical fact for the internal observers. They are not dictated by some Platonic mathematical universe.
 
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Klystron said:
And at least one branch of Wittgenstein's philosophy Logical positivism fell out of favor well within the 20th Century particularly after work by Karl Popper, among others. (https://en.wikipedia.org/wiki/Karl_Popper#Philosophy_of_science).

Popper's approach to the statement 2+2=4 appears simple but may offer guidance to understanding the implications of the original post.
2+2=4 doesn't concern itself with apples, it's a tautology.
2 apples +2 apples will not equal 4 apples just in case one apple does some transformation that adds another one to it. (like in the Banach-Tarski paradox, which is not physical as far as I can tell no physicist has been using this type of maths in his reasoning).
 

1. What is a multiverse model?

A multiverse model is a theoretical concept that suggests the existence of multiple universes beyond our own. These universes may have different physical laws, constants, and dimensions, and may exist simultaneously with our own universe.

2. How many types of multiverse models are there?

There are several types of multiverse models proposed by scientists and philosophers, including the bubble universe model, the many-worlds interpretation, the parallel universes model, and the brane cosmology model. Each model has its own unique characteristics and implications.

3. What evidence supports the existence of a multiverse?

Currently, there is no concrete evidence for the existence of a multiverse. However, some theories, such as inflationary cosmology and string theory, suggest the possibility of a multiverse. Scientists are also studying the cosmic microwave background radiation and gravitational waves for potential clues.

4. How does the concept of a multiverse impact our understanding of the universe?

The concept of a multiverse challenges our traditional understanding of the universe and raises questions about the nature of reality and our place in it. It also has implications for the search for extraterrestrial life and the concept of infinity.

5. Why is the multiverse model still a controversial topic?

The multiverse model is still a controversial topic because it is a highly theoretical concept with no concrete evidence to support it. It also challenges our current understanding of the universe and raises philosophical and ethical questions. Some scientists argue that it is not a testable hypothesis and therefore not a valid scientific theory.

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