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List of Statements Independent of ZFC

en.wikipedia.org

31–40 of 108 posts

Re: List of Statements Independent of ZFC

#31

Earlier quoted context omitted.

It is easy to prove for finite sets (just count) but much harder for infinite ones. For example, which has more subsets, the integers or the positive integers? How about the integers and the reals? If you answered "the integers" to the first question, you aren't thinking about this right, as the integers and the positive integers have the same number of elements to start with. source: https://en.wikipedia.org/wiki/Al…

Another example of why mathematics are a wrong abstraction to be optimally useful. Mathematics should have bounds in the same way as our universe has bounds. Any theorem that has a different behavior if something is infinite doesn't matter at all and is a waste of time for real engineers who solve things in the real world. The niche of mathematics that describe things beyond what our universe has to offer should be a…

Being "optimally useful" is not the goal of mathematics. See for example, https://www.dpmms.cam.ac.uk/~wtg10/2cultures.pdf

Re: List of Statements Independent of ZFC

#32
post #6
post #3

A very interesting discussion about this topic that also includes many examples and references is available on MathOverflow: What are some reasonable-sounding statements that are independent of ZFC? https://mathoverflow.net/questions/1924/what-are-some-reason... With the top voted result currently being: "If a set X is smaller in cardinality than another set Y, then X has fewer subsets than Y." As is also mentioned i…

That is a strange one.

Infinities are strange.

Re: List of Statements Independent of ZFC

#33

Earlier quoted context omitted.

It is easy to prove for finite sets (just count) but much harder for infinite ones. For example, which has more subsets, the integers or the positive integers? How about the integers and the reals? If you answered "the integers" to the first question, you aren't thinking about this right, as the integers and the positive integers have the same number of elements to start with. source: https://en.wikipedia.org/wiki/Al…

Another example of why mathematics are a wrong abstraction to be optimally useful. Mathematics should have bounds in the same way as our universe has bounds. Any theorem that has a different behavior if something is infinite doesn't matter at all and is a waste of time for real engineers who solve things in the real world. The niche of mathematics that describe things beyond what our universe has to offer should be a…

Tell all of the engineers using calculus that they don't need infinity.

And you can't easily only partially include infinity.

Re: List of Statements Independent of ZFC

#34
Is there any ELI5-type explanation for us non-mathers? Whenever I see stuff like this, I start trying to actually understand it, then fail miserably just trying to google terms I'm not familiar with. Is advanced knowledge of these math principles required to understand the significance of this page, or why it is interesting?

Re: List of Statements Independent of ZFC

#35
I recall once I read the short book "The Philosophy of Set Theory" [1] since I like philosophy and have an interest in Math. It contains much of the history that lead up to the decision to base significant portions of the soundness of mathematics on top of set theory (and by proxy: Cantor's work on infinities). My recollection is fuzzy since it was years ago but I recall it starts at Zeno's paradox and follows along to calculus and beyond.

The book suggests there was a lot of displeasure and argumentation within the philosophy and math communities because it was felt that there was no real basis for infinitesimals. Some mathematicians (I believe Hilbert and Frege among them?) became determined to shut-up the pesky philosophers by proving the soundness of math based on some logical axiomatic fundamentals. Of course, this was later proven to be impossible by Gödel but at the time they considered it a win that philosophers and mathematicians could at least agree on logic (and more broadly "logical empiricism" which is a basis of "analytical philosophy").

I recall being completely dissatisfied at the arguments presented in favour of ZFC (not mathematically, but philosophically). I remember there was a single paragraph somewhere in the final third of the book that I head to re-read several times before I finally gave up in frustration. My impression of this history is that the mathematicians "won" in some sense by railroading their ideas. Calculus works, right? It is extremely effective and leads to correct results ... so ignore the seeming paradox of summing an infinite quantity of infinitesimally small values and move on already! Further, ignore the actual paradoxes inherent in infinite sets. And this was all done not because there was some problem to be solved but rather to shut-down debate that seemed to undermine the philosophical position of logical empiricism.

Another interesting (if historically questionable) exploration of this topic is the graphic novel Logicomix [2]. This work follows Bertrand Russel and Wittgenstein through this period in our history.

1. https://www.amazon.com/Philosophy-Set-Theory-Introduction-Ma...

2. https://en.wikipedia.org/wiki/Logicomix

Re: List of Statements Independent of ZFC

#37
post #33

Earlier quoted context omitted.

Another example of why mathematics are a wrong abstraction to be optimally useful. Mathematics should have bounds in the same way as our universe has bounds. Any theorem that has a different behavior if something is infinite doesn't matter at all and is a waste of time for real engineers who solve things in the real world. The niche of mathematics that describe things beyond what our universe has to offer should be a…

Tell all of the engineers using calculus that they don't need infinity. And you can't easily only partially include infinity.

Could you give a use case?

Re: List of Statements Independent of ZFC

#40
post #6
post #3

A very interesting discussion about this topic that also includes many examples and references is available on MathOverflow: What are some reasonable-sounding statements that are independent of ZFC? https://mathoverflow.net/questions/1924/what-are-some-reason... With the top voted result currently being: "If a set X is smaller in cardinality than another set Y, then X has fewer subsets than Y." As is also mentioned i…

That is a strange one.

Try thinking about how you could probe that the integers have fewer subsets than the reals using ZFC.
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