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TonesInDeepFreeze

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That is not specification of an order, let alone of "THE inherent order". Of course, we could move left to right and also up and down, zigzagging to s...
June 04, 2021 at 03:38
I'm not sure, but I think a place to look might be proofs showing the relative consistency of anti-wellfoundeness. Maybe there is a construction in su...
June 04, 2021 at 03:34
Without the axiom of regularity, you can't prove ~Ex x = {x} = {{x}} = {{{x}}} ... for as finitely many iterations you want to make. As I said, if you...
June 04, 2021 at 03:30
Yes, there is an analogy and similarity, but also the modification used makes a great difference too.
June 04, 2021 at 03:19
x = {x} Read my previous post regarding proof and lack of proof of existence.
June 04, 2021 at 03:16
I too will plead, as at this time, especially as I am rusty in the subject, I wouldn't be able to marshal enough knowledge to explicate the details of...
June 04, 2021 at 03:14
I could only do that by using anti-foundation (or non-wellfounded) set theory. These are different: (1) The theory proves that there is not a set that...
June 04, 2021 at 02:55
See sections 4.4 and 4.5 here: https://plato.stanford.edu/entries/goedel-incompleteness/ For philosophical concerns about mathemtics see: https://www....
June 04, 2021 at 02:44
No, there are two kinds of proof involving contradiction: assume ~P derive contraction conclude P assume P derive contradiction conclude ~P The first ...
June 04, 2021 at 02:38
That doesn't sound right to me. The properties that are checked are syntactical. What semantical properties does Wikipedia claim are checked?
June 04, 2021 at 02:32
The incompleteness proof is intuitionistically valid and does not require excluded middle.
June 04, 2021 at 02:26
You said that I have difficulty stating the theorem. Stating a proof of the theorem is more than stating the theorem. I stated the theorem without dif...
June 04, 2021 at 02:24
There is no rule of set theory that we must name a set with set abstraction notation. Moreover, for a finite set with members that are members of them...
June 04, 2021 at 02:21
Yes, analogues.
June 04, 2021 at 02:03
I don't take exception to the Goldstein quote. But her book about incompleteness needs to be read critically. As I recall (though I can't cite specifi...
June 04, 2021 at 01:50
No. (1) The Godel sentence is not an equation. (2) "rules of math" is unclear. (3) We don't look outside the "rules of math" even given a reasonable u...
June 04, 2021 at 01:45
Yes, your quote from the book is well taken. And it is clear in the context of the book, but some people might not realize that context, so I just wan...
June 04, 2021 at 01:34
Aside from whatever SophistiCat might say, it is not the case that formalism regards the incompleteness theorem in that way. (1) Sentences are not tru...
June 04, 2021 at 01:32
To be clear, Franzen is taking exception to the theorem being incorrectly co-opted in many of those context.
June 04, 2021 at 01:13
"self-reference" used pejoratively in reference to Godel's theorem is a red herring. The self-reference is seen by looking outside the object language...
June 04, 2021 at 01:10
What you think about it is one matter. (What you think about it is based on a collection of confusions and misunderstandings you have.) But you said t...
June 04, 2021 at 00:53
Why don't you look up a text in set theory so you would know how set theory axiomatically, clearly and unambiguously proves theorems and defines terms...
June 04, 2021 at 00:47
"member of itself twice" has no apparent mathematical meaning.
June 04, 2021 at 00:42
But a couple of points: It's not inconsistent. It does not imply a contradiction. A contradiction is a statement and its negation. If you claim to poi...
June 04, 2021 at 00:39
Wrong. It is possible that all these are the case: x = {x y z} (so x is a member of itself), and y is a member of y, and y is a member of x, and z a m...
June 04, 2021 at 00:33
Set theory doesn't prove things in this kind of context by saying "the task cannot be completed". However, the axiom of regularity disallows infinite ...
June 04, 2021 at 00:18
You didn't go far enough in the argument: If there is a set of all sets, then it has the subset that is the set of all sets that are not members of th...
June 04, 2021 at 00:02
Usually, we have an intuitive notion that sets are not members of themselves. However, since 'is a member' is primitive, we will not have a formal exp...
June 03, 2021 at 23:59
With regularity, there is a set whose members are all and only those sets that are members of themselves. That set is the empty set. And if we drop re...
June 03, 2021 at 23:03
No, you know it. (1) is set theory proving there is no set whose members are all and only those sets that are not members of themselves. (2) is Tarski...
June 03, 2021 at 19:39
I don't like using markup. The text is plenty clear enough.
June 03, 2021 at 19:32
I didn't. No, I'm not violating separation. Separation and extensionality were used to prove the existence of 0 (in an axiomatization where the existe...
June 03, 2021 at 19:29
Are you serious? Come on, you know how to do it yourself: ZF |- ~ExAy(yex <-> ~yey) ZF |/- ~ExAy(yex <-> yey). ZF-R |/- ~ExAy(yex <-> yey) ZF |- ExAy(...
June 03, 2021 at 19:24
Russell's paradox shows the contradiction in set theory with unrestricted comprehension. After Russell's note, we moved to a set theory that does not ...
June 03, 2021 at 19:09
Looks okay now. No, I don't. Indeed, I said the opposite in my original post. Howzabout you quote me where you think I claimed that there exists a set...
June 03, 2021 at 18:57
Yes, when 'we' includes you. But with math, we do specify specific kinds of order. The notion of infinite sets is used calculus, which is mathematics ...
June 03, 2021 at 18:47
'before' and 'after' are often in a temporal sense, but clearly not exclusively. Not in English. And surely not in math that doesn't mention temporali...
June 03, 2021 at 18:43
Your math notation in your previous post does not format form me. Anyway, {x | ~xex} is not at question. There is no such set.
June 03, 2021 at 18:36
I don't think you mean {x | ~xex}. We're talking about {x | xex}. And yes, without regularity, we can't prove there is a nonempty set {x | xex}. But t...
June 03, 2021 at 18:23
That article gives an answer. It's a great article. (By the way, Panu Raattkainen is a top notch source on the subject.)
June 03, 2021 at 18:21
With regularity, It's the empty set. And we can't derive a contradiction by dropping an axiom, so such a set is consistent also without regularity. Bu...
June 03, 2021 at 18:10
Maybe I need to be double-checked, but my reasoning tells me that undecidability follows right from incompleteness.
June 03, 2021 at 18:02
It is terrible. I mentioned why earlier in this thread.
June 03, 2021 at 18:01
You mentioned the benefit of a course in logic. In another thread, I have listed what I consider to be the best textbooks leading to the incompletenes...
June 03, 2021 at 18:00
That is incorrect. Of course, to countenance sets being member of themselves, we have to delete the axiom of regularity. With that done: Suppose xex, ...
June 03, 2021 at 17:50
If you can correctly extract from the video that Godel's argument is circular, then the video is wrong. We should learn Godel's argument from a carefu...
June 03, 2021 at 17:25
I told you twice what Godel's theorem is: Instead of recognizing that, you bring up a different matter. You will not make any progress here if you can...
June 03, 2021 at 05:15
You have so many misconceptions. But let's take one thing at a time, starting here: Do you recognize that I did state Godel's theorem?
June 03, 2021 at 04:16
correction: When I said 'total linear ordering' I should have said 'strict linear ordering'.
June 03, 2021 at 03:07
I read fine. But with your lack of replies to many crucial points, I admit that I can't read what doesn't exist. Here is a previous post tracking your...
June 03, 2021 at 02:52