#Infinitism Vs Finitism
357 messages · Page 1 of 1 (latest)
How exactly is that proven? In any case, the proof must be somehow invalid. Because it appears all our observations are equally well-explained by a universe with discrete finite spacetime.
How in the hell do you plan to apply Cantor's diagonalization argument to... what, space?
Yeah. And your argument that the existence of ℵ₁ implies the existence of ℵ₀ is unjustified. Not to mention that the diagonalization argument itself assumes the existence of infinite strings of digits. Please elaborate.
thats not forbidden
that is some pseudo philosophical mumbo jumbo
work with whatever formal system you want
neither infinitism nor finitism is 'better' than the other
At least your're thinking differently
I like that
I think it has to do with interpretation
I think you can encode infinitism in finitism
inuitionism doesn't permit nonconstructive arguments
at the very least, the "encoding" will be difficult
What's finitism and infinitism actually?
broadly speaking, finitism = "only finite objects exist"
for intuitionists infinite objects like infinite sets don't (and can't) exist
the word "exists" is also another can of worms, entirely
their definition of N (the naturals) has something to do with memory capacity of computing devices
it's not a completely unreasonable position to take - computers don't "understand" and can't model the concept of "infinity"
any computer is bounded by 2^N bits of data, presumably there being some theoretical upper limit to maximum memory capacity
none of this is rigorous, take it as a tongue-in-cheek
rigorously speaking however: given sufficiently sophisticated formal system (one that encodes the arithmetic of N), the only way we have for determining whether it is "good" or "bad" is whether or not it produces contradictions
if we don't allow infinite objects, that's fine - but then that formal system wouldn't be useful for analysing infinite dimensional banach space theory
This is not something intuitionists generally believe.
also possible
I've also heard a certain mathematician saying the largest natural number is one that will be referenced by humans
Yes, those are ultrafinitists.
This is not really the case. Finitists have robust, ontological disagreements with infinitists. It's similar to saying, in response to a dispute amongst neccesitarians and non-necessitarians, that it just depends on what modal system you adopt.
disagreements naturally arise
mathematically speaking one should only worry about what the basic truths (axioms) are and what can be deduced from them
Yes, but you can dispute over the basic truths.
for something like CS, I would actually prefer constructivist approaches
Yes, same here.
indeed, but then that would be a philosophical debate
Indeed, but I don't really think there is nor ought to be a clear dermarcation between philosophy and all the other disciplines.
It's not as if our mathematical axioms (which tend to be formulated in natural language) and proofs which are accepted by other mathematicians just popped out of the ether.
im a mathematician, i am by default equipped to sh.t on philosophy 😂 
yeah, people tend to (mainly people who know nothing about it!)
though i wouldn't say you're equipped to
😂
ig maybe you are
like, a large number of post-20th century philosophers who started the analytic tradition had firm mathematical background for a reason
it's hard to interface with a lot of analytic philosophy without a firm logic background
im also compelled to shit on philosophy, but i don't really share the same tendency to just outright dismiss entire fields of study like some people do
difficult to put my position into words tbh
empirically speaking, such discussions (for me) have sooner or later come down to personal beliefs
i can't deny someone their belief
Ah, is the idea that certain disputes aren't empirically verifiable, and thus there is no real way to justify one view being correct over the other, or...?
something like that
math is simple in this regard
the rules of the game are fixed
but I don't know what the whole rulebook of philosophy is
kind of, the rules of the game are less apparent than you'd think
i have a natural inclination towards the accounts of people like Reuben Hersh or Imre Lakatos
hence I am content with all formal systems existing, their usefulness dependent on context
i mean, intuitionists don't tend to say "this formal system is haram" or something
it's much more like "in reality, PEM is false"
my belief (yup, here we go 😄 ) is that usefulness of theory A or B is dependent on context
what sort of problems are we trying to analyse
You're going to have to elaborate. Almost nobody will reject the "usefulness of theory A or B is dependent on context" simpliciter.
fair
That doesn't counteract any grand view though. Like, here's a good example of a view a lot of people who endorse classical logic hold: the very meaning of negation entails the PEM, so intuitionist logics negation means something different.
for example, I would (in most cases I can think of) require axiom of choice for banach space theory
and a lot of theory I am familiar with is predicated on the Hahn Banach theorem
Yes, well, keep in mind, most people do not want to put a ban on working in systems that contain AC as a theorem.
Like, formal systems are kind of divorced from what people who have these disputes care about
This is coming from someone who doesn't really think there's a fact in the matter of whether AC or PEM is true
Yes, PEM is LEM for people who don't want to call it a law, common sometimes among (certain) intuitionists
Yes
Which is why intuitionists have to reject it 😆
No, some philosophers (who are also mathematicians) of mathematics like to do a thing where they argue for some super intuitive thing Q, say it's true, and then show Q entails something like choice or the continuum hypothesis or something
What Woodin is doing comes to mind
However, this is all meaningless if you don't believe in what are frankly magic objects floating in the ether (mind-independent, aspatiotemporal "abstract objects")
I am reminded of how funny this is
oh boy ..
I was in some argument with one N. Wildberger some years ago over some philosophical mumbo jumbo
Oh, how did that go?
You say "mumbo jumbo," so I assume you didn't know what the words he was using meant.
he did enjoy sophistry, certainly
Exciting stuff, but this N J Wildberger fella I find online has a text literally titled "Divine Proportions"
Which is not a uh, good sign
he had an annoying condescending tone
ah, yeah, well that sucks
basically we were talkig about one of his essays where he criticised the ZFC axioms
I just should have known better that this premise alone is enough reason to avoid engaging with him altogether
eh, not all philosophers online are assholes (or sophists)
but I was in my "I feel like a god" stage of my math education
feeling like I should "save everyone"
saving everyone is a very noble goal, even if it is ultimately very misguided
so, what happened?
he talked in circles
I pointed that he is attacking his own strawman multiple times in the essay
essentially, he didn't criticise the axioms
damn, this guy seems somewhat respectable, teaching at UNSW
but rather his understanding of the axioms
which is pointless, imo
yes, and also dabbles in some very non trivial math
has written papers on Lie theory to name some
yes, i am looking through his stuff on ResearchGate
that's pretty good, he teaches history of mathematics at UNSW so it makes sense
but then he's hellbent on redefining analysis
if you like history of mathematics, i recommend you check out joel david hamkins
because the "real numbers" don't really make sense
ah, so it's some novel new type of analysis?
recognise this name from overflow too
indeed!
I was going to say
just now
"you may have seen him on mse or math overflow"
i think he does the same thing as analysis does now with limits
but he quantifies over Q
because that's somehow qualitatively different 😮
does he just dislike uncountability or something
Q seems ok so he's not ultrafinitist
or maybe he is, I don't know to be fair
he has said something about there being the largest natural number
he probably dislikes R because equality is not computable or something
haha
i dont rightly understand his position
Q seems fine for him
but he has also criticised the axiom of infinity
so he can't accept N (as an infinite set)
well, that's probably fine, it may be incoherent or something, but it also may be he didn't explain it well, or you don't have the philosophy background to make sense of his bad presentation or something, or a combination of the three
most likely a combination of the three
weird positions require a lot of deciphering to make sense of
eh, it probably is actually
sometimes there are weird philosophy-specific things, and if you touch enough logic, that's kind of inevitable since logic is basically at the junction between philosophy and mathematics, so the distinction gets fuzzy there
i'll try to read some of this guys stuff
but whatever my disputes with him, he definitely knows math, it's not all bogus stuff on his channel
okay, from his overview of Divine Proportions, his concern is that a lot of contemporary geometry is hard for people to understand because of the semantic vagueities of "infinite set theory"
oh yeah, he definitely doesn't like axioms
what he's doing doesn't actually seem all that bad, especially given how nice sufficiently weak systems are
i think his idea is actually just that we don't really have any understanding of this "infinitity stuff," so we should avoid it
which isn't all that bad, but i don't know what he uses to argue this is the case and what-not
and if he did say it like that, that would be fine with me
but he gets veeeery condescending
ah, that's a real shame, seriously
he claims that the ancient greeks and the reneissance folk were much more rigorous than we are today
haha, well it's hard for me to comment since i don't really know what he means by that, ancient greeks surely didn't prove theorems that turned out to be equivalent to AC in natural language, that's for sure
greeks didn't have any formal axioms or anything, obv
no formal proof checkers or anything either
theory wasnt as developed in the early 19th cty so many mathematicians/physicists used some claims because they were intuitively correct
famous example: continuous functions are differentiable almost everywhere
yeah, it's just plausible the dude thinks this is still the case more than we let on
bc of the axioms he doesn't like or something
and even more famous counterexample: weierstrass's continuous nowhere differentiable function
and even more, if what wildberger claimed was true
why oh why did hilbert go on to do what he did?
did the rigour of our ancestors got sucked into a black hole or something?
Are we talking about Hilbert's formalism stuff
hilbert's programme i think it's called
Yeah, well sadly that failed
but a good endeavor nonetheless
Indeed
pushed people like turing and gödel
There are systems like relevant PA (PA closed under entailment in relevant logic) which have finitistic proofs of their consistency, which is neat
good talk, gotta make dinner, tc buddy
alr, have fun and eat well
Dimensional space
Thanks
I totally acknowledge I could be wrong, which is why I said I think you could variably prove infinity to exist
Question to think about: How many squares are in a cube? (Hint: It's not 6)
If we break a cube down
There's an aleph 1 amount of squares
Another way to think about it: How do you go from a square to a cube with just squares? You need to somehow increase the third dimension from 0 to any positive number
How many numbers/decimals are there inbetween 0 and 1? Cantors diagonal argument pretty much self explanatorily applies to the amount of squares with no third dimension to make a third dimension
But other people could say something 2d doesn't exist and that it's an axiom
Which is again why I said variably since it depends how you look at it
"Variable proof" is not proof.
What are you even talking about?
No, there isn't. A square is a shape with literally zero thickness, any "slice" off of a cube must have a nonzero thickness. You can take the limit as the thickness approaches zero, but that's not remotely the same thing. A limit approaching 0 is not a value that achieves 0. Also this has nothing to do with Cantor diagonalization, and also also this presumes the continuity of space, which is supposedly the thing being proved, which makes it circular.
I don't think you understand
I'm just not gonna respond I fear you've not grasped the concept
I've grasped that you haven't taken calculus.
How old are you?
And I'm not old enough
So if you think you have a revolutionary theory about some field of math or science, but you're too young to have learned the math that is literally freshman level in that field, what's more likely; that you've noticed something that everyone else has missed, I guess because they were too busy going to all those classes you haven't taken, or that you've missed something that everyone else has noticed, maybe in all those classes you haven't taken?
'the math that is literally freshman level in that field'. Calculus is part of set theory?
I quite literally said I acknowledge I could be wrong, and I wasn't expecting to run into passive aggresive adults on this app who have degrees in maths? I thought someone with such knowledge wouldn't be sat in discord servers but I guess I was wrong
And do you have selective reading? Why only respond to some of what I've said
From what I've gathered on google, set theory is the standard foundation
..."freshman level" means "taught to college freshmen".
Something you learn in the first year of college.
And I'm not being passive aggressive, I'm making the point that you should take, like, literally any effort to seriously investigate an idea before you present it.
And if even that much feels over your head, you should acknowledge that you're probably just wrong.
Well yes you were
You started being passive aggressive before I even sent my theory
I find it sad that an adult is sat on discord to begin with, nevermind being passive aggressive to children and not even understanding what I've said
What do you think "passive aggressive" means?
That's fine, and I even acknowledge it
You sure as hell haven't explained that
Let's use our common sense
And again
Let's circle back to the selective reading part
I'll ask again
How old are you?
How can I "use common sense" to figure out what you think? Do you think "common sense" is the ability to read minds?
I fear common sense has the word common in it.. Common sense doesn't seem to be very common in you I guess?
Someone being passive aggressive means they're passively including unnecessarily remarks/ being aggressive in the way they talk
You could've deduced that if you'd utilised common sense
Definition is pretty much deduced within the phrase
Third time asking so hopefully will bypass your selective reading
How old are you?
It's not "selective reading", it's ignoring pointless nonsense.
I would like to know the age of the person I'm engaging in conversation with thank you
You say calculus is something taken in first year of college, I'm asking how old you are to see if I can figure out if you've taken it or not, or how deep you are in mathematics
I would like a billion dollars and a trip to the Moon.
I'm deducing from this you're either a child or an adult with a short temper
Based on your reply earlier, one with negligible comprehension skills and as established, no common sense
Nice chat
This is literally the first thing I said. Do you think this was passive aggressive? Because it wasn't. It was confused. I was confused because the sequence of words you said made no sense.
I think it encompassed unnecessary remarks
What I said did make sense, just not to you
Which now makes sense since we've established you've got no common sense
You could've simply asked me to elaborate/explain
I read 'How in the hell do you plan to-' with multiple dots to be passive aggressive
Although that could've been deduced with critical thinking from my previous replies on the topic... (yes this is me starting to be passive aggressive)
You have time to type all this but not 2 numbers
Well I'm hoping for 2 numbers
No, it didn't make sense because I knew what the words you said mean. Saying you can prove that infinity exists in reality using Cantor diagonalization is incoherent. I literally cannot think of an analogy for how little sense that makes that I'm confident you would be able to understand.
...do you expect me to have two ages?
I don't think you understand what incoherent means
Oh honey...
10^100. Now shut up about it.
You also think you can apply Cantor diagonalization to space, so it's pretty clear that what you think and what is true are two very distinct sets.
Thanks cause this made me laugh today
So did this
So, what I am trying to salvage out of 4 or whoever's beliefs (if we are to be charitable and call them that) is that
- Space is continuous
- If space is continuous, it is infinitely divisible
- If space is infinitely divisible, then infinity is "actual," thus infinitism is true
- Thus, infinitism is true
The best support I can give for 1 is in terms of the fact our best scientific theories commit us (to my knowledge) to a continuous view on space. GR doesn't make sense, to my knowledge, if spacetime is discrete, since uh, differentials and all. Premise 2 seems to be true, and 3 is dubious for obvious reasons.
Are the reasons 3 is dubious obvious to a middle schooler?
Depends on the middle schooler.
Uh, I can explain more if you'd like.
I wasn't talking about myself.
Yes, but that doesn't mean you wouldn't prefer I explain for others, no?
Such as middle schoolers who you think want to talk about infinitism.
No
1 and 2 yes not 3
I can't get over "realism" in your bio as if it is one specific position.
Are you a realist about everything, haha?
Numbers, God, also nonexistent objects, necessary beings that entail trivialism, et cetera, y'know?
Think of it less as dividing
Imagine a cube in your mind
How many squares make up that cube?
I'm not necessarily saying you can divide a cube by aleph 1 and you end up with a square
I'm saying looking at it from an upward perspective (if that at all makes sense) how many squares are needed to become a cube/cuboid. How many of these structures with no third dimension do we need to stack behind each other to give them a finite third dimension
Now back to the cube, let's say it has a width of 1 cm, height of 1 cm, and a length of 1 cm
We have 1 by 1 squares
How do we get that 1 by 1 square to a 1 by 1 by 1 cube?
You're going from 0 to 1
There are the same amount of 1 by 1 squares needed to make a 1 by 1 by 1 cube as there are decimals between 0 and 1
Which is why I said using cantors diagonal theory
The other guy who responded didn't understand my argument
The point is, I understand I might be wrong/ probably am, I'd just like someone to understand my theory before refuting it/ explaining to me why it's wrong
Meinong's Jungle Book.
Yes, well, sadly Meinong gets dismissed without thought because his view seems too absurd to people, since a lot of people are kind of bigots.
😭
In most of the things I've seen yeah
Russell does do a good blow to a lot of the reasons for Meinongianism though.
I mean it more in a world politics lense
I do understand it, and the problem is that 0 + 0 + 0 + 0 + 0 + 0 + ... = 0. Period.
😭 You don't
Okay, yeah, I still fail to understand this. As TL pointed out earlier, squares do not have any width in at least one direction when projected into 3D space.
*space, not plane.
Ah, thanks
I'm just gonna leave it here cause it makes sense in my mind and I'm just struggling to convey it in an understandable way
The problem is that you're assuming that an actual cube is infinitely divisible.
Yeah, so I think you're under the impression squares have some infinitesimal width or something.
But I do thank you for saying you don't understand it and that it's not 'not understandable'
Which is literally the thing you're trying to prove in the first place.
? I said 1 cm width
Oh
Bye
I didn't read
no dw
No it very much is not.
We can debate this if you want
What is there to debate over
An infinitesimal is literally by definition not 0.
It is literally by definition the smallest number greater than 0.
Like, it's just false
Which is why I said 'is also basically 0'
By definition it isn't, but it practically is
Infinitesimals are not additive identities
That's like saying 0.9recurring isn't 1 by definition but it basically is
It is, by definition, if you actually define 0.999... more precisely (in terms of limits, usually)
You don't get to say "it practically is" when it by definition is not.
Which is why I said we could debate it
You're not the penultimate consciousness
What is there to debate over? It's just false, no strings attached, unless you're going to bring in some weird verisimilitude notion here.
There's no point in a debate about the definition of a concept!
You haven't even taken calculus! What do you know about infinitesimals???
I don't think you understand what a debate is
You think it's false
I think it's true
That's quite literally the concept of a debate
Not to mention how abhorrently fallacious you guys' stance is
Eh, most calculus is not non-standard analysis, TL.
Most calculus students don't know anything about infinitesimals either. They're just a nice intuitive shorthand for doing limits, generally, almost never are they formalized.
That was more "you're so far below the level where you would know anything about this", not "you haven't taken the specific class that would teach you about this".
Ah.
What is up with the aggressive comments along side the ducking..
If you think you're so right then why not agree to debate this?
You think you're right, I think I'm right, let's debate it
Because literally your position in the "debate" is that the definition is wrong.

I mean, I don't think I've been rude to you much, 4.
So then it would literally be easy to debunk me..
Yes, which TL has just done.
I wasn't talking about you don't worry
You've actually been really nice
Which I've done! Like five times! And it hasn't stuck!
I haven't given my entire argument
Which is why I asked to debate it
Who's stopping you???
I'm asking to debate it with you
4, infinitesimals are kind of an abstract mathematical notion, I don't know if you're trying to tie it to something more physical in nature, by infinitesimals are defined in such a way that they do not resemble zero in any non-negligible way structurally.
What the fuck does "penultimately correct" mean???
I don't think it's entirely correct
That's not remotely what the word "penultimately" means.
In second place for correctness, I presume.
0 is typically supposed to be defined such that for all a, a + 0 = a, no? However, a + epsilon (where epsilon is some infinitesimal) does not equal a.
No I know I have no clue why I said that
I have no clue why you say anything I've seen you say so far.
Eh, you mixed up ultimately and penultimately, which happens, don't worry about it.
Sometimes it is useful to abstract away details like negligible factors and ignore them, but in some metaphysical context, this doesn't make much sense to do.
I think there's a difference between 0% and an infinitesimal percentage
I don't think an infinitesimal decimal is different to 0
You are right than infinitesimals have the nice property that a + k*epsilon for any natural k is always less than a + j for any real 0 < j.
See, the fact that you would say this, as though you perceive a percentage as something other than a number, just says it all.
I find it frustrating that I see you haven't understood my argument yet you disagree
Instead of asking me why, you just go straight to disagreeing
Which is why I asked how old you are cause you don't seem very intellectually mature
I don't see how this indicates they think percentages are something other than a number.
an infinitesimal decimal is different to 0
what is an infinitesimal decimal?
Why do you assume I haven't understood your argument?
I'm going out now but I can explain why I think that later
Infinitesimals do not have decimal representations in the usual sense.
Because you're disagreeing and I haven't elaborated enough for you to have understood what I mean...
Hey, if you would like to elaborate sufficiently, just write one long post when you get back.
Okay can you explain, in your own terms, what you think an infinitesimal decimal is so when I come back I can read cause I think you're intelligent
To me, an infinitesimal decimal would be 0.0(infinite 0s)1
Have you considered the possibility that I disagree because what you've already said is wrong, and therefore nothing that follows from it can be true?
If then, still, I or TL (if they still are entertaining this discussion, which they have no obligation to) do not understand, then it is probably because of an issue on your part, frankly. I do not think it's because TL is dumb or something.
Totally fine
To me, an infinitesimal decimal would be 0.0(infinite 0s)1
Cool, that's wrong.
It's uh, not necessariy wrong since they have yet to really explain what that means.
How about the inductive type definition of the naturals in lean. Would that be a finite object or an infinite object?
Thanks
Anyway
I'll come bacj later
They haven't taken calculus, they have no intelligible concept of what it means!
Yes, since people do not come up with ideas on their own, I'm sure.
It's not even intelligible! The closest analogue would be lim_(n -> inf) 1/10^n, which is just 0.
Well, again, we don't know what they mean.
They literally said they're not old enough to have taken calculus.
As I commented earlier,
Infinitesimals do not have decimal representations in the usual sense.
Have you seen "Sheafification of g" youtube videos?
I'm sure they will enjoy covering sheafs. How about we teach them about Ext and Tor too! /j
You're literally talking to a self-described child.
I do not think bringing age into the discussion for frankly no reason. Some children are precocious, and it really just serves to enforce stereotypes about children rather than accomplish anything at all.
I have only seen the ordinal videos
I have not seen anything by this "sheafification of g" fella.
To try everything Brilliant has to offer—free—for a full 30 days, visit https://brilliant.org/GSheaf/ . You’ll also get 20% off an annual premium subscription.
Finite numbers can be represented with finite strings of (decimal) digits, but what happens when we try to imitate this representation in the world of infinite numbers? In the world of o...
They're the ones who brought it up for no reason. I didn't ask, they just acted like I was bullying a child for telling them they were wrong about their incomprehensible gibberish.
This looks like a channel I would not enjoy watching.
How so
What the heck is an "infinite number"?
I think they mean there are infinitely many numbers that have only finitely many digits, but I'm not sure, maybe they clarify in the video.
I'm not going to watch it, since it seems like something that'd give me anxiety and is probably a load of pop mathematical hogwash, to be frank.
From the thumbnail, it looks like they're talking about numbers with infinitely many digits.
Then uh, yeah, you'll probably have to watch their content to find out.
It's about ordinals
He presents it in a way enjoyable for skibidi toilet watchers ig
But the mathematical content seems correct
Okay, so from the 2 minutes that I watched of this guy, he is basically just using some intuitions about ordinal numbers and not formalizing anything, which is frankly fine, since it is targeted at "skibidi toilet watchers."
Yea