Veteran TSZers may recall an entertaining thread in which a bunch of us tried to explain the cardinality of infinite sets to Joe G:
A lesson in cardinality for Joe G
At UD, commenters daveS and kairosfocus are now engaged in a long discussion of the transfinite, spanning three threads:
An infinite past can’t save Darwin?
An infinite past?
Durston and Craig on an infinite temporal past…
The sticking point, which keeps arising in different forms, is that KF cannot wrap his head around this simple fact: There are infinitely many integers, but each of them is finite.
For example, KF writes:
DS, I note to you that if you wish to define “all” integers as finite -which then raises serious concerns on then claiming the cardinality of the set of integers is transfinite if such be applied…
The same confusion arises in the context of Hilbert’s Hotel:
KF:
Try, the manager inspects each room in turn, and has been doing so forever at a rate of one per second. When does he arrive at the front desk, 0?
daveS:
Re: your HH explanation: If the manager was in room number -100 one hundred seconds ago, he arrives at the desk now.
KF:
Yes a manager can span the finite in finite time. But the issue is to span the proposed transfinite with an inherently finite stepwise process. KF
daveS:
In the scenario I described above, the manager was in room -n n seconds ago, for each natural number n. Given any room in the hotel, I can tell you when he was there.
KF:
DS, being in room n, n seconds past does not bridge to reaching the front desk at 0 when we deal with the transfinitely remote rooms; when also the inspection process is a finite step by step process.
What KF doesn’t get is that there are no ‘transfinitely remote rooms’. Each room is only finitely remote. It’s just that there are infinitely many of them.
Any bets on when — or whether — KF will finally get it?
Tom,
I still can’t figure out exactly what you are objecting to.
From your comments, I gather that in your view I have taken a wrong tack by “joining in” KF’s process of using “freestyle rhetoric” to make sense of mathematical concepts, making illegitimate use of the word “true” along the way.
Do you mean something else?
I’ve already addressed your objection to the word “true”:
Tom:
keiths:
Do you really object when someone says that “it’s true that 4+3=7” or “it’s false that 4+3=6”?
As for “joining in” with KF’s use of “freestyle rhetoric”, I’ve presented an explicit argument against KF’s intuition regarding the natural numbers:
That argument doesn’t strike me as “freestyle rhetoric”.
Could you explain, a bit more explicitly this time, what you are objecting to and why?
I’m more interested in knowing why Tom has ” loads of respect for Keith.”
Mung:
That makes sense. As someone who isn’t respected, you’d like to understand what others do to earn it.
🙂
Good one!
daveS asks KF point-blank:
KF dodges the question, of course, and doubles down on his misconceptions:
You don’t “arrive at transfinite cardinality”. When you go from a finite k to a finite k+1, you have simply arrived at k+1. The transfinite cardinality isn’t “arrived at” — it’s a property of the endless succession taken as a whole.
No. An infinite past would not mean that any point in the past was infinitely remote. Every point in the past is finitely remote; it’s just that there’s no end to those finitely remote points. Likewise, the fact that there are infinitely many natural numbers does not mean that any of them are infinite. It’s just that there are infinitely many finite natural numbers.
I, as an experiment, have written kf at UD with a very specific set of points and questions to see if he can focus on the simple topic of the nature of the natural numbers.
However, others have again brought up how this relates to the idea of a infinite past, and whether an infinite past is possible or not.
I have no interest in wading into a metaphysical morass with kf about the nature of time, but I’m willing, for the sake of discussion, to consider the number line as a model for time, with the integers being a model for seconds of time.
But I do have some thoughts, so I’ll post them here (out of kf’s sight), and get them out of my mind for the moment.
At UD, daveS made the interesting comment that “the existence of an infinite past just means that given any natural number n, the universe already existed n seconds ago.”
That seems right to me (although I’m thinking of time as extending before the start of the universe: that is one of the metaphysical issues I want to avoid.)
Just as an infinite future means there is no last moment of time, an infinite past means there is no first moment of time. Every moment has both a successor and a predecessor.
But kf, Spitzer et al add another element to the discussion that they see as inextricably connected: that time has within it a set of causally connected events.
That is, at every second k, there is an event Ek that is caused by the preceding event Ek-1 and causes Ek+1. Causality is one-directional: time has an arrow.
Therefore, to them, to say that time has no beginning is to say there is no first event, and thus no first cause, and as we all know, that is anathema to the “God as first cause” argument so predominant in Christian theology.
But if you separate the issue of some abstract infinite number line model of time from the issue of events happening within time, the theist could claim (note: I am not arguing for this), that time has an infinite past, but at some moment the first event happened.
To summarize, the question of an infinite past, using the number line as a model for time, is a separate issue from an infinite causally-connected uni-directional set of events with time. It is really the latter that is driving kf et al’s concerns. But since they are assuming that time and events in time are effectively co-incident, they can’t see the difference in the issues.
My thoughts for the morning.
I thought you wanted to avoid metaphysics. 🙂
You’re wrong here, but I don’t want to detract from your real purpose so won’t get into the theology or metaphysics of what is meant by a First Cause or Unmoved Mover.
I wanted to avoid talking metaphysics with kf, because I want to stay focussed on just the question of the nature of the natural numbers, so I posted these thoughts over here. The main point here is that the question of time and the question of events in time are two different issues. It does seem kf is concerned about metaphysical issues and first cause notions when he writes in the OP, “For, it seems the evolutionary materialist faces the unwelcome choice of a cosmos from a true nothing — non-being or else an actually completed infinite past succession of finite causal steps.”
As I said, I don’t want to discuss these issues – I’m just making the point that they are in the background of kf’s mind, and make it hard for him as he discusses the purely mathematical nature of the natural numbers. I think the idea of “an actually completed infinite past succession of finite causal steps” is the idea that he is really arguing about, and I think that idea is two different inter-mingled ideas, one about pure numbers and one about causally-connected events.
KF edges closer to an epiphany:
In other words, the natural numbers, which are constructed by “ascending count from 0”, are all finite. ω isn’t a natural number.
But confusion remains:
The set of natural numbers has a transfinite cardinality, but contains no transfinite numbers, “emergent” or otherwise.
Would he be happier if we added a fourth dot?
When your intuition clashes with a well-known mathematical fact, and you cannot find a flaw in the reasoning behind that well-known fact, then it is time to abandon your intuition.
It isn’t the numbers that “attain to cardinalities”. Cardinality is concerned with the size of a set, not the size of its elements.
And finally, a welcome bit of humility:
You’re just now figuring this out? And where did you post your proof?
The finite cardinal numbers are by definition the natural numbers. That’s not a proposition to be proved true or false. Keith has tried to construct persuasive quasi-arguments for the reasonableness of the definition. I disagree with that approach, because I think it contributes to the sound and the fury. But I don’t care enough about the matter to get into a fight about it.
Tom,
For the life of me, I can’t figure out why you regard my argument as a “quasi-argument”.
As far as I can tell, you don’t disagree with the premises, the reasoning, or the conclusion. So what makes it a “quasi-argument”?
KF is still off in the weeds. Aleta and daveS are trying to get him back on track, but he’s really, really confused.
What’s funny is that he’s becoming self-conscious about it. He can feel the eyes of the audience upon him:
Relax, KF. You’ve already blown it in the eyes of the audience. What’s left is for you to figure out why the mathematical community is right and you are wrong.
Highlights from the continuing KF trainwreck.
It’s like pulling teeth. Aleta and daveS are trying to get KF to state, unambiguously, whether he finally agrees that every natural number is finite.
Meanwhile, KF is inventing a new, entirely redundant symbol that he calls the EoE, or “ellipsis of endlessness”:
And:
And:
daveS tries to get a straight answer:
KF provides this non-answer:
Aleta:
Aleta:
Another non-answer from KF:
Aleta writes…
…and then repeats the question:
KF gives a non-answer concerning his non-answer:
Aleta:
KF finally makes it clear: he agrees that ω is not a natural number.
Aleta asks:
No response yet from KF.
Jesus H. Christ.
The wortgeschwurbel is metastasizing.
Aleta provides an apt diagnosis:
And:
Meanwhile, Mung stumbles in and draws an inapt analogy with divine simplicity:
Doesn’t it just burn you up that your lack of self-control got you banned from UD (again) and that you can’t post there and show kf just how wrong he is and how right you are? That must be seriously irritating. Here you are with all the right answers, yet … EoE …
Mung:
Here’s a learning opportunity for you, Mung. It’s math, but don’t be intimidated. The concept is quite simple:
Countable set
Pucker up, Sunshine.
This is hilarious:
All that verbiage, yet zero progress:
There is no “far zone of endlessness”, KF.
The entire sequence is endless. Endlessness is a property of the whole, not a property of some “far zone”.
The entire sequence is a “zone of endlessness”, including right at the beginning. There is no end at 0, no end at 1, no end anywhere else in the sequence. Yet that endlessness, which extends across the entire sequence, does not make 0 transfinite, and it does not make 1 transfinite. Why then should it magically bestow transfinitude on the natural numbers in some “far zone”?
There is no magic zone where adding one to a finite number somehow produces a transfinite number. Every natural number is finite, but there are infinitely many of them.
If KF is a physicist, I’m Emperor Palpatine
dazz,
Somewhat frighteningly, he has a M.Sc. in physics from the University of the West Indies.
Your Imperial Majesty.
Eternity is a long time, particularly toward the end.
Just call me Palpy :p
But seriously, if he doesn’t understand something as simple as the mathematical concept of infinity it doesn’t matter what credentials he has
petrushka,
It’s best to hit the restroom first.
dazz,
There are some shocking disconnects between credentials and abilities among the IDers. My favorite example is that of Rob Sheldon, PhD in physics from the University of Maryland, who wrote:
That’s just… amazing.
keiths,
You have to be kidding me, and it took him a year to realize such a basic mistake? Didn’t it occur to him to maybe try f(x) = x or something?
and he has the audacity to dismiss peer review altogether. What a fucktard
Petrushka wrote, “Eternity is a long time, particularly toward the end.”
That’s excellent.
And keiths says, “It’s best to hit the restroom first.”
I believe that last restroom is at the restaurant at the end of the universe.
Maybe, instead of moving into the zone of endlessness, time just rocks back and forth: k, k + 1, k, k + 1, …
Aleta,
You forgot the “EoE”. 🙂
KF is quite the problem student. I applaud you and daveS for your patient pedagogy.
KF writes:
Ironically, it is KF who is effectively trying to “end the endless”.
His faulty intuition seems to run something like this:
1. If I take 7 natural numbers starting from 1, the sequence ends at 7.
2. If I take 73 natural numbers starting from 1, the sequence ends at 73.
3. If I take infinitely many natural numbers starting from 1, the sequence ends at infinity, or in the “transfinite zone”, or in the “zone of endlessness”.
The error couldn’t be more obvious. In #3, the sequence doesn’t end. If it did, then the set of natural numbers wouldn’t be infinite. To assume that there is an ending point where the final number is infinite is to contradict oneself. KF is effectively assuming an end to endlessness.
He papers over this a bit by referring not to an endpoint, but rather to a “transfinite zone” or a “zone of endlessness”, but the error is the same. He is assuming that there is a point within the sequence where infinity is attained and completed — an end to the endlessness. It’s just that he starts counting up again from that “point” and calls the new sequence the “zone of endlessness”.
There is no point within the sequence where infinity is attained. There is no last number, no “transfinite zone”, no “zone of endlessness”. What makes the natural numbers endless is that there is no end. For every finite n, there is a finite n+1. Endlessly.
KF:
Aleta:
Aleta,
Perhaps you could point out that when KF speaks of a “far end” to an endless sequence, he is speaking nonsense.
It’s amazing to me, and fascinating, that he can’t see it.
Meanwhile, Mung is confused as usual:
Thanks, keith. I’m sticking with the discussion with kf for several reasons. One, I’m interested in the math. Second, I’m a math teacher, and I like trying to explain things to people. One of the things I learned from many years of teaching is that trying to find out what the student misunderstands is often a key to getting them able to learn what they are not getting.
In addition, I’ve had many “conversations” at UD on many subjects which, I’m sure you know, get caught in a morass of dedicated unwillingness to try to even understand a different point of view. And, more particularly, kf is renowned for some of the discussion habits that we are seeing in his discussion. But, and this is what is keeping me around, is that is this case it’s math, and much more clearcut (one would think) then theology or evolution or metaphysics, etc.
So the opportunity is here, as an exercise in psychology, pegagogy, and techniques of constructive dialog, to see if kf can move away from his habitual style of discussion. Can he separate issues, and can he possibly say, “Oh, I see what you are saying”, and change his mind from his original position? I think we are seeing many of the same problems, but there has been some differences in tone and a willingness to couch his position as concerns as opposed to pretty inviolable assertions.
So I keep sticking around despite my claim that I’m going to quit.
And you’ll notice I steadfastly refuse to start talking about the reals, infinitesimals, etc. That is a not a place that I would be willing to sink my time.
And it’s been good to have the Skeptical Zone as a place to have some offsite feedback and discussion.
Thanks,
“Aleta”
Well, this isn’t my speciality, but I thought everyone here has argued well against KF.
That said, if I can add my two uniformed cents.
It seems to me that finite is formally defined to mean bounded. That is, if there exists a natural number n, it is bounded from above by (n+1). That’s all it really means to say than any given n is finite.
The fact that the set of naturals is infinite then makes it possible to make every n finite. That is for every n, there exists a bound from above, namely n+1.
To say we have a natural number n equal to infinity is to say there is no n+1 that bounds it from above. That makes little sense as far as I can tell.
At issue is the meaning of finite is not clearly defined. If we say finite means bound from above by some other number, then it is easy to show all naturals n are bounded from above by some other number, namely, n+1.
The fact this can be done for every n implies the set of naturals is infinite.
At least that’s how I resolve the paradox. The problem is one of an ambiguous definition of finite.
PS
One of my 3 undergrads was in math, but I wouldn’t ever call myself a mathematician. I’m not that good.
Sal,
To establish that some particular n is finite, it isn’t enough to show that n is bounded by n+1, unless you also show that n+1 is finite.
You need to do that from below, not from above.
Sal,
No, the standard definitions are unambiguous.
And interestingly, the exact definition doesn’t matter, as long as your interlocutor accepts this premise:
I think KF would be hard pressed to dispute that.
The same inductive step from n to n+1 that is used to construct the naturals also establishes their finitude, if you accept that premise.
KF’s position is bizarre and contradictory: he accepts the construction but rejects the induction, when both can be expressed using the same logic.
The only consistent way for him to maintain his position is to deny the premise above — which would be absurd.
There cannot be an infinite number, because each increase in the number increases the amount of energy required for it to increase again. That is, if we had an infinite number, then there would be an infinite amount of energy, and we would be able to travel at the speed of light, violating relativity, which Einstein proved mathematically to be true.
Fortunately, the astute and articulate Mapou has shown us that relativity is false:
It must chafe his ass to see yet another confirmation of GR in the news.
Just as long as they’re not dressed in cheap tuxedos.
I’m not sure I get this. An infinite number of what would necessarily imply infinite energy? Are you talking about space-time (vacuum energy)?
He’s joking, dazz.
Ouch, 😀
Let S be the set of natural numbers less than or equal to a a natural number n. The set of those natural numbers can be placed into a one-to-one correspondence with the set of those natural numbers less than the natural number n+1. Hence n is finite.
We show this for 1, and then 1+1, by induction we show this for all natural numbers, hence all natural numbers are finite, and this is possible because the set of natural numbers is infinite. Paradox resolved.
Btw, I care less and less about what KF thinks, engaging him is an exercise in practising how to dealing with obfuscation.
Agreed, we start with n = 1.
We show n+1 is finite because it is bounded from above by ( ( n+1) + 1).
Rinse and repeat.
Sal,
How you feel about KF is how I’m sure many people feel about you.
Sal says, “Btw, I care less and less about what KF thinks, engaging him is an exercise in practising how to dealing with obfuscation.”
Well I’ll be darned – I agree with Sal (and there’s been many a time in the past when I disagreed with him.)
Hello Emperor Palpy.
😀
Meanwhile over at UD they are asking “what paradox.”
As for me, I am waiting for Richardthughes to post a link to a youtube video where Seth Lloyd explains what gravity is.