I answered this in my most recent post to you. Given two ordinals, it's always the case that one is an element of the other or vice versa. — fishfry
This is NOT true of sets in general, but it IS true for ordinals, and that's what makes the construction work. — fishfry
No, as I'm pointing out to you. It's true that every ordinal is cardinally equivalent to itself, but that tells us nothing. You're trying to make a point based on obfuscating the distinction between cardinal numbers, on the one hand, and cardinal equivalence, on the other. — fishfry
Other way 'round. A cardinal number is defined as a particular ordinal, namely the least ordinal (in the sense of set membership) cardinally equivalent to a given set. — fishfry
Right. I can live with that. I know I have the same number of fingers as my glove, but I don't know how many fingers that is. — fishfry
Cardinal equivalence is a relation between two sets. It's not something a set can have by itself. — fishfry
I see where you're going with this. Given a set, it has a cardinal number, which -- after we know what this means -- is its "cardinality." You want to claim that the set's cardinality is an inherent property. But no, actually it's a defined attribute. First we define a class of objects called the cardinal numbers; then every set is cardinally equivalent to exactly one of them. But before we defined what cardinal numbers were, we couldn't say that a set has a cardinal number. I suppose this is a subtle point, one I'll have to think about. — fishfry
But when you got up that morning, before you came to my party, you weren't a room 3 person or whatever. The assignment is made after you show up, according to a scheme I made up. Your room-ness is not an inherent part of you. — fishfry
Incorrect: We should not use 'least' if we don't mean quantity.
It is typical of cranks unfamiliar with mathematical practice to think that the special mathematical senses of words most conform to their own sense of the words or even to everyday non-mathematical senses. The formal theories don't even have natural language words in them. Rather, they are purely symbolic. Natural language words are used conversationally and in writing so that we can more easily communicate and see concepts in our mind's eye. The words themselves are often suggestive of our intuitions and our conceptual motivations, but proofs in the formal theory cannot appeal to what the words suggest or connote. And for any word such as 'least' if a crank simply could not stomach using that word in the mathematical sense, then, if we were fabulously indulgent of the crank, we could say, "Fine, we'll say 'schmleast' instead. 'schmardinality' instead'. 'ploompty ket' instead of 'empty set' ... It would not affect the mathematics, as the structural relations among the words would remain, and the formal symbolism too. — TonesInDeepFreeze
df: K is a cardinal iff K is an ordinal and there is no ordinal j less than K such that there is a bijection between K and j.
There is no mention of 'cardinal' or 'cardinality' in the definiens. — TonesInDeepFreeze
You wouldn't call it "my" theory of relativity, or "my" theory of evolution, just because I happened to invoke those well-established scientific ideas in a conversation. — fishfry
It's a bit like saying that the score in a baseball game is tied -- without saying what the score is. Maybe that helps. — fishfry
If one thing is defined in terms of some other thing, the latter is logically prior. As is the case with cardinal numbers, which are defined as particular ordinal numbers. — fishfry
I'd agree that given some ordinal number, it's cardinally equivalent to some other sets. It doesn't "have a cardinality" yet because we haven't defined that. We've only established that a given ordinal is cardinally equivalent to some other set. — fishfry
Note per your earlier objection that by "least" I mean the ∈∈ relation, which well-orders any collection of ordinals. If you prefer "precedes everything else" instead of "least," just read it that way. — fishfry
No. Cardinal equivalence is logically prior to ordinals in the sense that every ordinal is cardinally equivalent to some other sets. At the very least, every ordinal is cardinally equivalent to itself.
When you use the word "cardinality" you are halfway between cardinal numbers and cardinal equivalence, so you confuse the issue. Better to say that cardinal equivalence is logically prior to ordinals; and that (in the modern formulation) ordinals are logically prior to cardinals. — fishfry
Socrates does not make the proper distinction between a tuning and what is tuned. It is not more or less a tuning, it is more or less in tune. — Fooloso4
Well, does it now appear to do quite the opposite, ruling over all the elements of which one says it is composed, opposing nearly all of them throughout life, directing all their ways, inflicting harsh and painful punishment on them, at times in physical culture and medicine, at other times more gently by threats and exhortations, holding converse with desires and passion and fears as if it were one thing talking to a different one... — 94c-d
The proper analogy to good and bad souls would be good and bad tunings. — Fooloso4
The problem for moderns, is that 'prior to' must always be interpreted temporally - in terms of temporal sequence. However, I think for the Ancients, 'prior to' means logically, not temporally prior. 'The soul' is eternal, not in the sense of eternal duration, but of being of an order outside of time, of timeless being, of which the individual is an instance. I think that comes through more clearly in neo-Platonism but the idea is there from the outset. — Wayfarer
But you say it's "my" bijective equivalence as if this is some personal theory I'm promoting on this site. On the contrary, it's established math. You reject it. I can't talk you out of that. — fishfry
Two sets are bijectively equivalent if there is a bijection between them. In that case we say they have the same cardinality. We can do that without defining a cardinal number. That's the point. The concept of cardinality can be defined even without defining what a cardinal number is. — fishfry
Cardinality is inherent. — fishfry
His argument is that Harmony is a universal. What is at issue is the difference between the universal and particular. Harmony itself is prior to any particular thing that is in harmony. — Fooloso4
So yes, cardinality is already inherent within the ordinals. Each ordinal has a cardinality. I — fishfry
Not at all. Not "more or less," but "prior in the order," if you prefer more accurate verbiage.
You insist on conflating order with quantity, and that's an elementary conceptual error. In an order relation x < y, it means that x precedes y in the order. x is not "smaller than" y in a quantitative sense. I can't do anything about your refusal to recognize the distinction between quantity and order. — fishfry
The modern definition is the von Neumann cardinal assignment. Von Neumann defined a cardinal as the least ordinal having that cardinality. — fishfry
The soul is that which imparts life to the body in the first place (105c - d). Without the soul there would be no body. — Apollodorus
Right, but a lyre is not a living thing. It is not capable of self-movement or self-attunement.
Wayfarer makes an important point: — Fooloso4
With all his talk of opposite forms Socrates neglects to consider Harmonious /Unharmonious or — Fooloso4
The question is why Socrates neglected this argument? — Fooloso4
Second, the argument that the soul is a harmony means that the fate of a particular soul is tied to the fate of a particular body. — Fooloso4
The analogy with the lyre is not with a lyre that needs to be tuned but that is tuned, that is, in harmony. — Fooloso4
I do not know the tuning of the lyre, but let's say the strings are tuned in 4ths or 5ths. The standard is independent of any particular lyre, but whether this particular lyre is in tune cannot be independent of the tension of the strings of this lyre, and that tension cannot be achieved when this lyre is destroyed. — Fooloso4
God is supposed to be a necessary being. Something is necessary if it is true in every possible world. — Banno
Logic is needed in order to have the discussion, not as a consequence of the discussion. — Banno
The tuning does not tune the lyre or body, the lyre or body is tuned according to the tuning. It must exist in order to be tuned. — Fooloso4
But if the argument is accepted then the soul is not immortal. The destruction of the lyre means the destruction of its tuning, and analogously the destruction of the body would mean the destruction of its tuning. How a lyre or body is tuned according to the relationship of its part is not affected, but the tuning of this particular lyre or body certainly is when the lyre or body is destroyed, — Fooloso4
The tuning of a lyre exists apart from any particular lyre. — Fooloso4
It is this relationship of frequencies that is used to tune a particular lyre. — Fooloso4
Analogously, the Tuning of the body exists apart from any particular body, it is the relationship of bodily parts, but the tuning of any particular body suffers the same fate as the tuning of any particular lyre. — Fooloso4
But pi is not a particular real number? How can I have a conversation with you? — fishfry
Pi is a particular real number, known to the ancients. Hardly a principle. — fishfry
Are you saying that because humans are physical and sets are a product of the human mind, that sets are therefore physical? — fishfry
Well then your point is trivial and pointless. Everything is physical if we can imagine it. The Baby Jesus, the Flying Spaghetti Monster, the three-headed hydra, all physical because the mind is physical. Whatever man. Pointless to conversate further then if you hide behind such a nihilistic and unproductive point. — fishfry
Can we please stop now? — fishfry
Some aspects of mathematics is so obviously fictional that it is UNREASONABLE that math should be so effective in the physical sciences. — fishfry
If you drop a set near the earth, it doesn't fall down. Sets have no gravitational or inertial mass. They have no electric charge. They have no temperature, velocity, momentum, or orientation. In what sense are sets bound by the real world? — fishfry
except that -- stretching a point -- mathematical objects are products of the human mind and the human mind is bound by the laws of nature. So perhaps ultimately there's a physical reason why we think the thoughts we do. I'd agree with that possibility, if that's the point you're making. — fishfry
In math, violating the "fundamental principles" is how progress is made. — fishfry
I've just shown that some of the greatest advances in math have been made by blowing up the opinions of the world. What happens is that the opinions of the mathematical world change. Or as Planck said, scientific progress proceeds one funeral at a time. Meaning that the old guard die off and the young Turks readily adopt the radical new ideas. — fishfry
Sure the pieces are made of atoms, but there is no fundamental physical reason why the knight moves that way. — fishfry
That math is inspired by the world and not bound by it? To me this is a banality, not a falsehood. It's true, but so trivial as to be beneath mention to anyone who's studied mathematics or mathematical philosophy. — fishfry
But it's still a formal game. — fishfry
That's an interesting point. Yet you can see the difference between representational art, which strives to be "true," and abstract art, which is inspired by but not bound by the real world. Or as they told us when I took a film class once, "Film frees us from the limitations of time and space." A movie is inspired by but not bound by reality. Star Wars isn't real, but the celluloid film stock (or whatever they use these days) is made of atoms. Right? Right. — fishfry
I recognize the difference between pure and applied mathematics. And you seem to reject fiction, science fiction, surrealist poetry, modern art, and unicorns. Me I like unicorns. They are inspired by the world but not bound by it. I like infinitary mathematics, for exactly the same reason. Perhaps you should read my recent essay here on the transfinite ordinals. It will give you much fuel for righteous rage. But I didn't invent any of it, Cantor did, and mathematicians have been pursuing the theory ever since then right up to the present moment. Perhaps you could take it up with them. — fishfry
The concept of infinite infinities is already part of mathematics today. Therefore, in your dubious distinction between mathematics and “imaginary fictions”, your placement of infinite infinities on the side of "imaginary fictions" makes no sense; infinite infinities is already on the side of mathematics. Your attempted stipulations to the contrary are pointless. — Luke
How can you argue with the truth of things that are not claimed to be true? Nobody claims that the axiom of replacement or the axiom of powersets is true. NOBODY says that. — fishfry
It's entirely analogous. Chess is a formal game, there's no "reason" why the knight moves as it does other than the pragmatics of what's been proven by experience to make for an interesting game. And there are equally valid variations of the game in common use as well. — fishfry
Of course math is inspired by the world. It's just not bound by it. A point I've made to you a dozen times by now. — fishfry
News to me. — fishfry
Wow! I am really impressed to realize Omar Khayyam (1048-1131) had the perspicacity to realize his efforts at Non-Euclidean geometry involved notions of space-time. Thanks, MU. I would not have guessed. :chin: — jgill
I'm not arguing my point of view is right, I'm not even arguing a point of view. I'm telling you how modern math works. It's like this, if you don't mind a Galilean dialog. — fishfry
Modern math is what it is, and nothing you say changes that, nor am I defending it, only reporting on it. — fishfry
It was forced on math by the discovery of non-Euclidean geometry. Once mathematicians discovered the existence of multiple internally consistent but mutually inconsistent geometries, what else could they do but give up on truth and focus on consistency?
I'm curious to hear your response to this point. What were they supposed to do with non-Euclidean geometry? Especially when 70 years later it turned out to be of vital importance in physics? — fishfry
It's not good or bad, it is simple inevitable. What should math do? Abolish Eucidean or non-Euclidean geometry? On what basis? — fishfry
As evidence I give you "The unreasonable effectiveness of math etc." — fishfry
You've given me not the slightest evidence that you have any idea how math works. And a lot of evidence to the contrary. — fishfry
I'm curious where you came across this. I've only seen it once, from Eva Brann, but don't recall if she cited any supporting evidence. — Fooloso4
I think the "Passion" of Christ refers in the first place to the suffering of Christ from late Latin passio "suffering, experience of pain". Though, I guess you can use it in the sense of "strong will" if you want to. — Apollodorus
Yeah, I'm using the word an insane amount of times. But in this case, I just meant that you're quite mad. — Kenosha Kid
Sad preacher nailed upon the coloured door of time
Insane teacher be there reminded of the rhyme
There'll be no mutant enemy we shall certify
Political ends, as sad remains, will die
Reach out as forward tastes begin to enter you
— Yes, And You and I
Modelling, hypothesis, observation: so far, so scientific, not to mention that inflationary cosmology comes from scientific research groups, not philosophical ones, and the founders of the theory have won prizes for breakthroughs in science, not metaphysics. — Kenosha Kid
So on that level, calling it metaphysics not science is insane — Kenosha Kid
You are insane. — Kenosha Kid
Cosmology – a central branch of metaphysics, that studies the origin, fundamental structure, nature, and dynamics of the universe. — Wikipedia: Outline of Metaphysics
The spirited part of the tripartite soul in the Republic, for example, is not spiritual in the sense I think you are using the term. — Fooloso4
All perfectly sound, but note that your definition of it is given in a specific context, or domain of discourse, rather than an attempt to define the term 'spirit' in a general sense. — Wayfarer
The reason I don't like 'spiritual' is because of its many different uses, and also the different and sometimes conficting meanings of 'spirit' — Wayfarer
It is what the education in music is supposed to moderate. — Fooloso4
I also am ambivalent in respect of the word 'spiritual'. The terms I'm familiar with are psyche, nous, and logos. — Wayfarer
When I was in my early teens, no one at school spoke of “Platonism”. It was always individual authors like Plato, Aristotle, Plotinus. So, when I first read Plato’s dialogues like Timaeus, Symposium, Republic, I was unaware of the existence of a system called “Platonism”. — Apollodorus
If we insist that there were major changes, for example, from Plato to Plotinus, we should be able to show what those changes are and to what extent (if at all) they are inconsistent with (a) the text of the dialogues and (b) with how Plato was understood in the interim. — Apollodorus
And the focus of that way of life, at least within the Academy, was the positive construction of a theoretical framework on the foundation of UP. — Apollodorus
Here I briefly sketch a hypothetical reconstruction of what I shall call ‘Ur-Platonism’ (UP). This is the general philosophical position that arises from the conjunction of the negations of the philosophical positions explicitly rejected in the dialogues, that is, the philosophical positions on offer in the history of philosophy accessible to Plato himself. — Platonism Versus Naturalism, Lloyd P. Gerson, University of Toronto
Well, much more than 37bn. Part of inflation theory is that the universe must be much, much larger than the observable universe. However, no magic necessary, just counting. 2c for two adjacent points. Next add a third. You have points A, B and C in a row. A is receding from B at almost the speed of light. B is receding from C at roughly the same speed. How fast is A receding from C? — Kenosha Kid
These issues were not completely resolved in Plato's times and had to be worked out later. — Apollodorus
