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How has mathematics gotten so abstract?

lcamtuf.substack.com

91–100 of 220 posts

Re: How has mathematics gotten so abstract?

#91
post #89
post #2

This reminds of of that one time when I was on a date with a girl from the history department who somehow bemusedly sat through my entire mini-lecture on comparing infinite sets. Twenty years and three kids later, she'll still occasionally look me straight in the eye and declare "my infinity is bigger than your infinity."

I'm curious. Did either of you ever notice the implicit philosophical assumptions that you have to make to come to the conclusion that one infinity can be larger than another? Despite the fact that this was actively debated for decades, modern math courses seldom acknowledge the fact that they are making unprovable intellectual leaps along the way.

> Despite the fact that this was actively debated for decades, modern math courses seldom acknowledge the fact that they are making unprovable intellectual leaps along the way.

That’s not at all true at the level where you are dealing with different infinities, usually, which tends to come after the (usually, fairly early) part dealing with proofs and the fact that all mathematics is dealing with “unprovable intellectual leaps” which are encoded into axioms, and everything in math which is provable is only provable based on a particular chosen set of axioms.

It may be true that math beyond that basic level doesn’t make a point of going back and explicitly reviewing that point, but it is just kind of implicit in everything later.

Re: How has mathematics gotten so abstract?

#92
post #65

Earlier quoted context omitted.

I think it is fair to say that it was always an abstraction. But, crucially, it was built on language as much as it was empiricism. That is, numbers were specifically used to abstract over how other things behave using simple and strict rules. No?

> That is, numbers were specifically used to abstract over how other things behave using simple and strict rules. No? Agree that math is built on language. But math is not any specific set of abstractions; time and again mathematicians have found out that if you change the definitions and axioms, you achieve a quite different set of abstractions (different numbers, geometries, infinity sets...). Does it mean that the…

Agreed that we grew math to be that way. But there is an easy to trace history on the names of the numbers. Reals, Rationals, Imaginary, etc. They were largely named based on their relation to the language on how to relate them to physical things.

Re: How has mathematics gotten so abstract?

#93
None of that was even the abstract stuff. It is all models of sizes, order, and inclusion (integers, cardinals, ordinals, sets). Not the nastier abstractions of partial orders, associativity, composition and so on (lattices, categories, ...).

Re: How has mathematics gotten so abstract?

#94

How has blog posts authors gotten so uneducated or/and clickbaiting? Math in its core has always been abstract. It’s the whole point.

> Math in its core has always been abstract. It’s the whole point.

I don't think so. E.g. there may be some abstractions in numerical linear algebra, but the subject matter has always been quite concrete.

Re: How has mathematics gotten so abstract?

#96
post #93

None of that was even the abstract stuff. It is all models of sizes, order, and inclusion (integers, cardinals, ordinals, sets). Not the nastier abstractions of partial orders, associativity, composition and so on (lattices, categories, ...).

And yet it all circles back.

We used Peano arithmetic when doing C++ template metaprogramming anytime a for loop from 0..n was needed. It was fun and games as long as you didn't make a mistake because the compiler errors would be gnarly. The Haskell people still do stuff like this, and I wouldn't be surprised if someone were doing it in Scala's type system as well.

Also, the PLT people are using lattices and categories to formalize their work.

Re: How has mathematics gotten so abstract?

#97
post #88

Proposed rule: People writing about the history of mathematics, should learn something about the history of mathematics. Mathematicians didn't just randomly decide to go to abstraction and the foundations of mathematics. They were forced there by a series of crises where the mathematics that they knew fell apart. For example Joseph Fourier came up with a way to add up a bunch of well-behaved functions - sin and cos -…

Yeah... The article doesn't even attempt to answer the question in its title. It's just a watered down Intro to Mathematics 101.

Re: How has mathematics gotten so abstract?

#98

Unlike Zeno's famous example the paradox which does better at explaining the problem is https://en.wikipedia.org/wiki/Coastline_paradox which Mandelbrot seemed particularly keen on. The tendency towards excessive abstraction is the same as the use of jargon in other fields: it just serves to gatekeep everything. The history of mathematics (and science) is actually full of amateurs, priests and bored aristocrats that…

Complaining about jargon is lazy. Most communications about complicated things are not aimed at the layman, because to do anything useful with the complicated things, you tend to have to understand a fair amount of the context of the field. Once you're committed to actually learning about the field, the jargon is the easiest part: they're just words or phrases that mean something very specific.

To put it another way: Jargon is the source code of the sciences. To an outsider, looking in on software development, they see the somewhat impenetrable wall of parentheses and semicolons and go "Ah, that's why programming is hard: you have to understand code". And I hope everyone here can understand that that's an uninformed thing to say. Syntax is the easy part of programming, it was made specifically to make expressing the rigorous problem solving easier. Jargon is the same way: it exists to make expressing very specific things that only people in this subfield actually think about easier, instead of having to vaguely gesture at the concept, or completely redefine it every time anybody wants to communicate within the field.

Re: How has mathematics gotten so abstract?

#100

Unlike Zeno's famous example the paradox which does better at explaining the problem is https://en.wikipedia.org/wiki/Coastline_paradox which Mandelbrot seemed particularly keen on. The tendency towards excessive abstraction is the same as the use of jargon in other fields: it just serves to gatekeep everything. The history of mathematics (and science) is actually full of amateurs, priests and bored aristocrats that…

Abstraction isn't to gatekeep; it's to increase the utility. It's the same as "dependency inversion" in programming: do your logic in terms of interfaces/properties, not in terms of a particular instance. This makes reasoning reusable. It also often makes things clearer by cutting out distracting details that aren't related to the core idea.

People are aware that you need context to motivate abstractions. That's why we start with numbers and fractions and not ideals and localizations.

Jargon in any field is to communicate quickly with precision. Again the point is not to gatekeep. It's that e.g. doctors spend a lot of time talking to other doctors about complex medical topics, and need a high bandwidth way to discuss things that may require a lot of nuance. The gatekeeping is not about knowing the words; it's knowing all of the information that the words are condensing.

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