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124 votes
17 answers
18k views

Pressure to defend the relevance of one's area of mathematics

I am a set theorist. Since I began to study this subject, I became increasingly aware of negative attitudes about it. These were expressed both from an internal and an external perspective. By the “...
15 votes
1 answer
985 views

Does inner model theory seek canonical models for large cardinals?

Like the author of this question, I have heard that a main goal of inner model theory is building canonical inner models for large cardinals. My questions are: (a) Is this accurate? (b) If so, in ...
Monroe Eskew's user avatar
  • 18.6k
0 votes
2 answers
582 views

Why are model theorists free to use GCH and other semi-axioms? [closed]

Looking into the open problem section of the book Model theory by Chang and Keisler, I noticed that many problems assumed semi-axioms like GCH. I talk about 'semi-axioms' because these "axioms" are ...
user99445's user avatar
-1 votes
1 answer
319 views

Tarski-Grothendieck in the cumulative hierarchy

How can the Grothendieck-Tarski axiom seen to be true in the cumulative hierarchy of sets? What are intuitions that would convince us that this axiom is true?
user99371's user avatar
0 votes
1 answer
678 views

Why do we try to encode every mathematical object as a set? [closed]

Probably everyone of us has seen set-theoretic encodings of mathematical objects which we wouldn't naturally consider to be sets. May it be the "definition" of a function from $A$ to $B$ as a relation ...
user98612's user avatar
50 votes
4 answers
6k views

Do set-theorists use informal set theory as their meta-theory when talking about models of ZFC?

Here, Noah Schweber writes the following: Most mathematics is not done in ZFC. Most mathematics, in fact, isn't done axiomatically at all: rather, we simply use propositions which seem "intuitively ...
user98009's user avatar
  • 509
21 votes
2 answers
2k views

Philosophical arguments in defense (or against) large cardinals

The question is essentially what is asked in the title. I split it into two parts (A) (Arguments supporting the existence of large cardinals) What are the main philosophical arguments in defense of ...
3 votes
0 answers
342 views

A Question Regarding Boolean-valued Models

What were the intuitions motivating the creation (or discovery, if you will) of Boolean-valued models? I have searched for the Scott-Solovay paper on the subject, but to no avail. There also seems to ...
Thomas Benjamin's user avatar
22 votes
4 answers
4k views

Are proper classes objects?

Many of us presume that mathematics studies objects. In agreement with this, set theorists often say that they study the well founded hereditarily extensional objects generated ex nihilo by the "...
Cole Leahy's user avatar
  • 1,081
31 votes
3 answers
5k views

Should there be a true model of set theory?

As I understand it, there is a program in set theory to produce an ultimate, canonical model of set theory which, among other things, positively answers the Continuum Hypothesis and various questions ...
Amit Kumar Gupta's user avatar
67 votes
10 answers
14k views

Arguments against large cardinals

I started to learn about large cardinals a while ago, and I read that the existence, and even the consistency of the existence of an inaccessible cardinal, i.e. a limit cardinal which is additionally ...
user8996's user avatar
  • 825
26 votes
9 answers
8k views

Why are proofs so valuable, although we do not know that our axiom system is consistent? [closed]

As a person who has been spending significant time to learn mathematics, I have to admit that I sometimes find the fact uncovered by Godel very upsetting: we never can know that our axiom system is ...
39 votes
5 answers
6k views

Why do categorical foundationalists want to escape set theory?

This is a question that I have seen asked passively in comments relating to the separation of category theory from set theory, but I haven't seen it addressed in full. I know that it's possible to ...
Eric's user avatar
  • 855
11 votes
5 answers
9k views

Models of ZFC Set Theory - Getting Started

For just any first-order theory: What are the sets I am supposed/allowed to think of when thinking of models as sets (of something + additional structure)? Provided: I can think of models of any ...
Hans-Peter Stricker's user avatar
17 votes
8 answers
2k views

The Importance of ZF

It seems as though many consider ZF to be the foundational set of axioms for all of mathematics (or at least, a crucial part of the foundations); when a theorem is found to be independent of ZF, it's ...
Jimmy Miller's user avatar