You might think, that "the meaning is always clear from context", but if you go back and reread TIDF's discussion of counting a quantity, you'll see the equivocation with order.
I'm taking this from the end of your post and addressing it first to get it out of the way. As I mentioned, I didn't read any posts in this thread that didn't mention my handle. I only responded to one single sentence of yours to the effect that numbers are about quantity. I simply pointed out that there is another completely distinct use of numbers, namely order. Anything else going on in this thread I have no comment on.
All I saw in you demonstration was a spatial ordering of symbols. I really do not see how to derive a purely abstract order from this. If you truly think that there is some type of order which is intelligible without any spatial or temporal reference, you need to do a better job demonstrating and explaining it.
I assure you, I am very interested to see this demonstration, because I've been looking for such a thing for a long time, because it would justify a pure form of "a priori". Of course, I'll be very harsh in my criticism because I used to believe in the pure a priori years ago, but when such a believe could not ever be justified I've since changed my mind. To persuade me back, would require what I would apprehend your demonstration as a faultless proof. — Metaphysician Undercover
I may not be fully aware of the philosophical context of your use of "a priori." Do you mean mathematical abstraction? Because I am talking about, and you seem to be objecting to, the essentially abstract nature of math. The farmer has five cows but the mathematician only cares about the five. The referent of the quantity or order is unimportant. If you don't believe in abstraction at all (a theme of yours) then there's no hope. In elementary physics problems a vector has a length of 3 meters; but the exact same problem in calculus class presents the length as 3. There are no units in math other than with reference to the arbitrarily stipulated unit of 1. There aren't grams and meters and seconds. There's no time or space, just abstract numbers. I don't know how to say it better than that, and it's frustrating to me that you either pretend to not believe in mathematical abstraction, or really don't.
Looking ahead a bit I will try to explain abstract order after I respond to your other remarks.
There is an issue though, that I'll warn you of. Any such demonstration which you can make, will be an empirical demonstration, using symbols to represent the abstract. — Metaphysician Undercover
You can't get civilization off the ground without abstract symbolic reasoning, from language to math. Even music has a notation. But the notation is not the music, I hope you'll agree. Likewise the notational explanation of ordinals won't be the ordinals. I can show you the symbols but you have to hear the music on your own. That's the tricky bit, right?
This is a good point so I'll repeat it. You would not confuse music with its notation; so I hope you'll indulge my mathematical notation in the service of communicating abstract ideas. The ideas aren't the notation. We agree on that. You seem to want to deny the ideas themselves simply because they're abstract. That's the part of your viewpoint I don't understand.
So the onus will be on you, — Metaphysician Undercover
To explain to you the theory of ordinal numbers? I don't know if I can do that but I'll give it a shot.
to demonstrate how the proposed "purely abstract order" could exist without the use of the empirical symbols, — Metaphysician Undercover
No. That can't be right. You are correct that I believe that there is a notion of purely abstract order; and that I'm constrained to talk about it using symbols that are not the actual things being talked about. But you can't reject my presentation because of that. You can't deny the quest for justice just because it's an abstract idea that is not literally present in the string "justice." If you reject all human abstractions, there's no point in my starting, because you'll just say, "Oh that's only symbolic representation of things that don't exist." I can't overcome that level of nihiism.
or else to show that the empirical symbols could exist in some sort of order which is grounded or understood neither through temporal nor spatial ideas. — Metaphysician Undercover
Well, as it happens, Cantor discovered ordinal numbers when he was studying the zeros of Fourier's trigonometric series; which were an abstract mathematical model of heat distribution. That is, one can make the case that if you heat up one end of an iron bar under lab conditions, and carefully measure how the heat travels to the rest of the bar; you will inevitably discover the transfinite ordinals. There is physics behind abstract order theory. Nevertheless, the theory stands on its own as an expression of the notion of purely abstract order.
I'll tell you something else though, I have opted for a sort of compromise to this problem of justifying the pure a priori, by concluding that time itself is non-empirical, thus justifying the temporal order of first, second, third, etc., as purely a priori. — Metaphysician Undercover
I see your annoyance. I want to talk about first, second, third, but I don't want to relate them to first base, second base, or third base. I want to regard ordinals as pure ideas that can be arranged in purely abstract order. If you utterly reject that then we're done. All I can do is try to explain how mathematicians view the subject of abstract order. I can't convince you that such a thing exists. But I don't need to. I can fall back on formalism and say that even if it doesn't exist, it's a fun mental pastime, like chess. There's no physical referent for chess but it's fun and educational and some practitioners take it very seriously indeed. But it's not real. I'm sure I've made this analogy before.
However, this requires that I divorce myself from the conventional idea of time which sees time as derived from spatial change. Instead, we need to see time as required, necessary for spatial change, and this places the passing of time as prior to all spatial existence. — Metaphysician Undercover
There is no need for time or space in math. I can't talk or argue or logic you out of your disbelief in human abstraction.
This is why I said what I did about modern physics, this position is completely incompatible with the representation of time employed in physics. In conceiving of time in this way we have the means for a sort of compromised pure a priori order. It is compromised because it divides "experience" into two parts, associated with the internal and external intuitions. The internal being the intuition of time, must be separated from "experience" to maintain the status of "a priori", free from experience, for the temporal order. So it's a compromised pure a priori. — Metaphysician Undercover
And yet they get 13 decimal places of agreement between theory and experiment. That has to count for something. It's all we've got. It's helped us to crawl out of caves and build all this. For whatever that's worth.
I didn't deny the distinction between quantity and order, I emphasized it to accuse Tones of equivocation between the two in his representation of a count as bijection. — Metaphysician Undercover
I can't comment on your conversations in this thread that I didn't read. But as a technical matter, in cardinality theory we care about bijections. In order theory we care about
order-preserving bijections.
That is exactly why I attack the principles of mathematics as faulty. There are empirical principles based in the law of identity, by which a physical, and sensible object is designated as an individual unit, a distinct particular, which can be counted as one discrete entity. There are no such principles for imaginary things. — Metaphysician Undercover
Doesn't Captain Kirk = Captain Kirk? Look, we're never going to get to ordinals at this rate. I don't know what you mean that the law of identity doesn't apply to fictional entities but there's a whole philosophy of fictional entities that I don't know much about.
Imaginary things have vague and fuzzy boundaries as evidenced from the sorites paradox. so the fact that "there is no mathematical difference between counting abstract or imaginary objects...and counting rocks", is evidence of faulty mathematics. — Metaphysician Undercover
You just phrase things like that to annoy me. How can you utterly deny human abstractions? Language is an abstraction. Law, property, traffic lights are abstractions. So is math.
As I said, all you've given me is a representation of a spatial ordering of symbols. If you are presenting me with something more than this you'll have to provide me with a better demonstration. — Metaphysician Undercover
This thread's already long. Do you want me to talk about ordinals or not?
I go both ways on this. Of space and time, one is continuous, the other discrete. But this is another reason why I think physics has a faulty representation of space and time, they tend to class the two together, as both either one or the other. — Metaphysician Undercover
Ok, you reject math, you reject physics. And you miss the distinction between physics and metaphysics, between a mathematical model and the thing being modeled. Whatever. Let me talk about ordinals.
Ordinals as abstract order types
========================
I'll keep this relatively brief since the rest of the post is long. I hope we can talk about ordinal numbers and not have any more endless disagreements about human abstraction. Our capacity for abstraction is one of the foundations of civilization, along with the opposable thumb. It's pointless to argue about it.
Ok first finite sets. You have a class full of school kids. You line them up by height. Or you line them up alphabetically by last name. Two distinct ways of ordering the same set. One cardinality but two distinct orders.
However, you will observe that these two distinct orderings nevertheless have the same
order type. By that I mean that there is an
order-preserving bijection between the set of kids in height order, and the set of kids in alpha order. You just match the first to the first, the second to the second, and so forth.
It's not hard to believe, and not hard to prove, that any two distinct orderings of a finite set have the same order type; in other words, that there is an order-preserving bijection. or
order isomorphism, between the two orders. So orders on finite sets aren't very interesting.
So now, infinite sets. In fact only one infinite set is of interest to us at the moment, the natural numbers
.
I hope you will grant me the abstract existence of this set, else there's nothing to talk about.
And I hope you won't be so tedious as to complain, "Well those dots are bullshit and they don't really stand for anything or mean anything blah blah blah." I pretty much agree with you, literally. The notation is only
suggestive of a deeper abstract truth, that of the idea of an endless progression of things, one after the next, with no end, such that each thing has an immediate successor. Again if you want to stand on a soapbox and deny that, there's no point in this conversation. You have to at some level believe -- or at least accept, for purposes of playing the game -- the reality of such an endless progression.
is not the symbol or the list in brackets with the mysterious dots at the end. That's only a notation for the music. I want you to imagine the music, and form an association in your mind between the symbols, and the deeper abstract idea they represent. Surely you must be able to do this, after all you do it just fine using the English language. It's not really any different. Meaningless symbols that stand for abstract ideas. You do it every day with letters and words. It's no different in math.
Now the set of natural numbers
has no inherent order. You may recall that sets have no order. The set {a,b,c} and the set {b,c,a} are the exact same set. This is in fact the
axiom of extensionality in set theory. It says that one of the rules of the game of set theory is that two sets are the same if and only if they have the exact same elements.
So given this set
, we would like to put an order on it. What is an order? Well again, we play a symbolic game. We say that an
order is a binary relation on a set that's reflexive, antisymmetric, and transitive. These terms are defined in the Wiki article I linked but they're not important. What is important is that they characterize the binary relation that we usually call
, the "less than or equal" relationship.
In the present case we also require that the order be
total, in the sense that given two elements
and
, either
or
.
And finally for convenience in this context, we prefer to work with the
strict order , which works like "less than or equal" but we disallow the equal; that is,
is disallowed. Again this is all common sense that you already know, the details aren't important.details aren't important.
What IS important is that we have defined order
without regard to any external meaning. It's all a formal symbolic game.
Then, we can formally define the symbols 0, 1, 2, 3, ... according to
von Neumann's clever idea such that
Having done this, we now have a formal definition of each natural number within the rules of set theory; and then we can make the definition:
just in case
.
The point of all this is that we can define the '<' relation
without regard to quantity and without regard to time or space or anything physical or meaningful. It's just an arbitrary symbol in the formal game of set theory; in principle no different to saying how the knight moves in chess.
Having done that, we have defined what's known as the
usual order on
. It's the order you learned in grade school, the one everyone knows. But the point is that I have defined '<' in such a way that
this order relation means nothing at all other than the formal relation of set membership; which in set theory actually has no definition at all.
is an undefined symbol, just as point and line are in Euclidean geometry.
Having now stripped the usual order of any meaning, I'm free to define alternate orders like
that I defined earlier; which is the same order as
except that
for all
.
This is clearly an alternate order on
, just like lining the kids up by height versus by alpha last name. But in this case, these two orders represent
distinct order types. There is in fact no conceivable way to create an order-isomorphism between these two ordered sets
and
.
We can see this because
has
no largest element, and and
does: namely, 3.
Now what I have outlined is the mathematical point of view in which:
* Order is an
entirely arbitrary and meaningless binary relation on a set;
* That there are multiple possible orders on a given set; and that
* In the case of infinite sets, there can be distinct orders that are also distinct order types; that is, there are distinct orders that can not be put into order-isomorphism with each other.
This is the foundation of the idea of ordinal numbers, which are just order types of sets. And in passing, I hope I have made the point that while you object to the meaninglessness of math; on the contrary, it's the very meaninglessness of math that is essential! We have stripped all notion of external meaning from the order relation; in order to be able to investigate the properties of order without regard to the things that may be ordered.
What you call a vice, math calls a virtue.
Meaninglessness, or lack of reference to anything tangible, is the heart of the power of mathematical abstraction.
As Wiles said when he proved Fermat's last theorem at a conference: "I think I'll stop now."