[HN Gopher] How the modern world arose from imaginary numbers
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       How the modern world arose from imaginary numbers
        
       Author : CapitalistCartr
       Score  : 23 points
       Date   : 2022-02-10 12:13 UTC (10 hours ago)
        
 (HTM) web link (nautil.us)
 (TXT) w3m dump (nautil.us)
        
       | adityapatadia wrote:
       | This is one video which shows history of imaginary numbers and
       | their usefulness in current times.
       | 
       | It's from Veritasium: https://www.youtube.com/watch?v=cUzklzVXJwo
        
       | gumby wrote:
       | "Imaginary" was an unfortunate choice of word. Positive integers
       | and rationals feel "legit"* to most people, even (or especially)
       | the non-mathematically trained.
       | 
       | But "imaginary" numbers are no more or less legit than, say,
       | transcendental numbers. But in middle school you learn this
       | confusing thing and maths starts to fall off the rails.
       | 
       | * Had to find a synonym for "real" here.
        
         | jdrc wrote:
         | Yeah we should stop using the word imaginary, and just call
         | them iNumbers (sorry Apple)
        
           | Qem wrote:
           | I like to call them "double-barreled numbers". I never liked
           | the term "imaginary", because that gives mystical
           | connotations and even hamper understanding, in my opinion.
        
         | intrepidhero wrote:
         | That's what I've finally settled on in my mind. Since we use
         | imaginary numbers to model and measure real phenomenon, they're
         | not imaginary in the sense that I would usually use that word.
         | There's got to be a better name... Transcendental complement
         | maybe.
        
       | viktorcode wrote:
       | I highly recommend video by Sabine Hossenfelder [1] on this
       | topic. She's explaining the topic in layman terms, starting from
       | what does it mean to exist (or be real) in physical sense.
       | 
       | Complex numbers, as useful as they are, just an abstraction, a
       | tool which can be replaced with different forms of calculations.
       | That makes the question of "reality" rather complex (pardon the
       | pun).
       | 
       | [1] https://www.youtube.com/watch?v=ALc8CBYOfkw
        
         | Psyladine wrote:
         | For those interested I also highly recommend Veritasium's
         | video[1] as an excellent explainer as well, especially
         | regarding the roots of imaginary/complex numbers in geometry.
         | 
         | [1] https://www.youtube.com/watch?v=cUzklzVXJwo
        
       | [deleted]
        
       | nuncanada wrote:
       | Mathematicians have been constantly been giving bad names do
       | their concepts... Imaginary Numbers is one of the atrocious ones,
       | Imaginary Numbers are part of the fabric of our reality...
       | Meanwhile Real Number were axiomatized in a way that creates
       | completely unrealistic numbers, "ghost-like" numbers, numbers
       | that can never be given a name... The first course in Analysis is
       | ridden with examples of Continuous Functions that are not
       | continuous in any sense humans would consider ever it...
        
       | dandanua wrote:
       | Life is complex - it has real and imaginary parts.
        
       | 1970-01-01 wrote:
       | I've been calling them invisible numbers most of my life. It
       | makes much more sense.
        
       | Agamus wrote:
       | I'm not an expert here, but truly interested to hear responses to
       | this question.
       | 
       | To say that 1+1=2 is "true", does that not require a corollary in
       | "reality" to something fundamental that can be called a "one"
       | object? I believe this is called mathematical constructivism.
       | 
       | Imagine, hypothetically, that we cannot identify something that
       | is physically fundamental and individual. My question is whether
       | any mathematics in that scenario could be considered "true"
       | without such constructivism, in other words, without a physical
       | correspondence to an unquestionably, physically fundamental "one"
       | object.
        
       | hgomersall wrote:
       | There is a persuasive school of thought that argues exactly the
       | opposite, that imaginary numbers are not real
       | http://geometry.mrao.cam.ac.uk/1993/01/imaginary-numbers-are... .
        
         | topaz0 wrote:
         | I'm familiar with (and partial to) the geometric algebra
         | literature, but I think it's a bit disingenuous/clickbaity to
         | say that it implies imaginary numbers aren't real. I think of
         | it as meaning that the algebra of the imaginary numbers arises
         | as a slice through a more useful, bigger algebra.
        
           | hgomersall wrote:
           | Yes, I think it's rather tongue in cheek. It's probably not
           | defined as clickbait since it was written in '93!
        
       | dboreham wrote:
       | This is only mentioned in passing in the article, but the penny
       | dropped for me when I read somewhere else that you should first
       | think about negative numbers. They seem pretty real, but they're
       | not. There's no negative quantity in nature. You can't have -5
       | rocks. Negative numbers are just the solution to equations of the
       | form x + n = 0. Now after you let that sink in, imaginary numbers
       | don't seem so weird after all. Just another kind of number
       | defined as the solution to some equation.
        
         | TheOtherHobbes wrote:
         | You can owe someone five rocks (or dollars, to make it only
         | slightly less abstract.)
         | 
         | You can go five miles east instead of west (more of a vector,
         | but still makes sense if your movements are limited to a number
         | line instead of a number plane).
         | 
         | Imaginary numbers are more of the same with a twist. i is just
         | a pi/2 rotation on a plane instead of a negative number, which
         | can be thought of as rotation by pi on a line.
         | 
         | The big mistake with imaginary numbers is calling them
         | imaginary. There's nothing imaginary about them. They're a very
         | specific kind of operation which can be expanded with very
         | little thought or effort to complex numbers, which have
         | incredibly useful properties in engineering.
         | 
         | Calling them "imaginary" is cripplingly confusing for almost
         | everyone, and many never get over it.
        
         | redler wrote:
         | You could have five exactly rock-shaped holes in the ground,
         | and by adding seven rocks, only two remain above the surface.
        
         | mettamage wrote:
         | I disagree.
         | 
         | > You can't have -5 rocks
         | 
         | You can have 5 rocks destroyed in the future. That to me, is
         | what -5 physically means: a guarantee that the object
         | associated with the number will be eliminated out of existence
         | in the future and decrement the negative number by 1.
         | 
         | Some people call it debt, but to me, emotionally that word
         | feels too financial. So I prefer "a guarantee to be eliminated
         | out of existence in the future ", or something like that.
         | 
         | Conversely, 5 cows means: 5 cows currently in existence.
         | 
         | 5 cows - 5 cows means: I see 5 cows and now they don't exist
         | any more and there is nothing.
         | 
         | I wish my math skills were better, I am optimistic that I'd
         | find a similar thing for imaginary numbers and maybe even
         | complex numbers.
         | 
         | With that said, I do get where you're coming from and I find it
         | a compelling perspective as well. It's simply that I feel the
         | perspective I described as well.
        
           | easywood wrote:
           | >> You can have 5 rocks destroyed in the future You have 5
           | rocks now, and zero rocks in the future. At no point are
           | there negative rock-shaped holes in the fabric of space. The
           | parent's comment still stands, he is talking about reality,
           | not our mathematical interpretation of it.
        
           | marcus_cemes wrote:
           | > You can have 5 rocks destroyed in the future.
           | 
           | Exactly, you use it to store some information that has no
           | real quantity but may be converted to a real quantity in the
           | future through some other process.
           | 
           | I'm a polytechnic university student, we use imaginary
           | numbers extensively in all sorts of places, especially
           | whenever there is any oscillatory behaviour, such as an
           | electrical signal or a light wave. A complex number is just a
           | two-dimensional vector with real/imaginary components, whcih
           | provides an amplitude and a phase (angle). An oscillating
           | sinusoidal signal/wave may appear to be zero and completely
           | static if you freeze time at the right moment, but as time
           | progresses, it will continue oscillating, like a swing in a
           | park.
           | 
           | In a way, the magnitude represents the built up "momentum" of
           | the system, whilst the real quantity is the immediate
           | physical value at any given point in time (given by the
           | phase). The amplitude is always the same at any given moment,
           | even when the swing is vertical, it has momentum which will
           | help it reach its maximum height.
           | 
           | Personally, I still think they are just "invented", but I
           | think the vast majority of engineers much prefer them to the
           | alternative, manipulating trigonometric functions (every
           | engineer's nightmare). They're a neat way to represent the
           | exchange of potential and mechanical/electrical energy with a
           | single value and some simplified mathematics (this is an
           | engineer's, not a mathematician's, point of view). Like
           | negative numbers, we could have chosen to have two positive
           | quantities, balance and debt, instead we find use in merging
           | these definitions, whether negative values make sense or not.
           | We have become used to to negative numbers representing the
           | "inverse" action, which makes sense when representing a
           | phyiscal quantity such as velocity.
        
           | taco_emoji wrote:
           | You're not actually disagreeing. OP is saying the negative
           | numbers are useful _conceptually_ , which is what you're
           | demonstrating here.
           | 
           | Also thinking about a number line is useful when talking
           | about both negative numbers AND complex ones: negative
           | numbers are to the left of 0, but complex numbers are _up and
           | down_ from the number line.
        
       | phendrenad2 wrote:
       | Imaginary numbers are just a shorthand way of representing things
       | in nature that relate to one another via the sine function, for
       | example, charged particles in a magnetic field. You can bust out
       | calculus to describe the motion, or you can use a convenient set
       | of rules that represents the partially-solved equation.
        
       | nyc111 wrote:
       | > For some reason--whether a sense that there was some mistake,
       | or someone copied something down wrong, or because it was so
       | absurd--the manuscripts we have show that Heron ignored the minus
       | sign and gave the answer as [?]63 instead.
       | 
       | I wonder if the minus sign was in use in the time of Heron (First
       | century AD). I couldn't tell from this Wikipedia page
       | https://en.wikipedia.org/wiki/Plus_and_minus_signs
        
       | dTal wrote:
       | Another way to think of it is that _all_ numbers are imaginary.
       | 
       | Numbers aren't real. Platonism is wrong. Imaginary numbers aren't
       | "out there" somewhere. The whole system of mathematics is an
       | accumulated edifice of metaphors designed by human brains, for
       | human brains, and there's no god "behind the curtain". It's just
       | a tool of thought. It reflects the "reality" of the universe only
       | insofar as we've looked at the universe, noticed patterns, and
       | constructed metaphors around them.
       | 
       | This is not a popular viewpoint! But it is the only
       | scientifically supported one.
        
         | voldacar wrote:
         | This is one particular point of view, and it's extremely sloppy
         | reasoning to say that it's "scientifically supported", given
         | that mathematics is not a form of science.
         | 
         | There are plenty of very smart people, not just mathematicians
         | but also physicists & scientists who are mathematical
         | platonists.
        
           | dTal wrote:
           | There are plenty of smart people - scientists even - who
           | believe in all kinds of deities.
           | 
           | Mathematics is indeed not a form of science. But the
           | existence and shape of mathematics is an observable
           | phenomenon, and so _meta_ mathematics - the study of what it
           | is and where it comes from - _can_ be studied scientifically.
           | How do you know mathematics exists? Well, there 's a textbook
           | right there. Who wrote the textbook and why? A human,
           | expressing metaphors inside their heads. How did those
           | metaphors get inside that human's head? Ah, well, that's the
           | interesting bit - the answer of course transpires to be "a
           | combination of innate ideas imprinted by genetic evolution by
           | natural selection, and sociology". And you don't have to stop
           | there, you can explore in glorious detail exactly _where_
           | each idea comes from, what innate monkey-ish tendency is
           | being deployed, how exactly ideas like  "infinity" fit in a
           | mind designed for finding fruit and chasing things.
           | 
           | We can similarly bring all manner of religious beliefs under
           | the anthropological knife. It's not a pretty process though,
           | to the people who believe in them.
        
             | carapace wrote:
             | > metaphors inside their heads.
             | 
             | You're begging the question presupposing the non-Platonic
             | viewpoint here. How do we know that metaphors are "inside
             | the head"?
        
             | voldacar wrote:
             | You are just assuming the point you're trying to prove
             | 
             | > There are plenty of smart people - scientists even - who
             | believe in all kinds of deities.
             | 
             | Okay? This is supposed to make me feel - how exactly? I'm
             | not inherently disdainful towards theism or theists, but if
             | I were, I guess your remark would make me like science
             | less, or something?
             | 
             | > We can similarly bring all manner of religious beliefs
             | under the anthropological knife
             | 
             | I'm not really sure we can, actually. At least not in some
             | kind of non-contentious, "objective" sense. I don't really
             | trust individual humans to give an accurate account of why
             | they believe their beliefs, but I trust "anthropology" and
             | "sociology" even less. My distrust for this on an
             | individual scale comes from the fact that many beliefs &
             | memes exist for purposes of social signalling, group
             | identification, etc, and it might not actually be in your
             | interest to know exactly why you believe what you do.
             | 
             | But these auxiliary functions of beliefs, such as
             | signalling etc, seem to me to scale _up_ as you introduce
             | groups and larger-scale activities such as  "anthropology"
             | and "sociology". Without some feedback loop keeping them
             | honest, why would I expect anthropologists or sociologists
             | to tell me a true story about why someone believes what
             | they do, any more than that person or anyone else? In
             | aerospace engineering, the feedback loop is that if your
             | design is bad, your jet engine won't work. As a result, I
             | generally trust aerospace engineers about jet engines. But
             | what is there to stop sociologists, anthropologists, etc
             | from just settling on some bullshit that agrees with their
             | preconceived beliefs or flatters their group status and
             | promoting it forever?
             | 
             | But back to math. The history of mathematical ideas is
             | complicated and interesting, but it isn't really that
             | relevant to the question of whether the things those ideas
             | are _about_ are  "real", which is equivalent to asking
             | whether mathematical platonism is true or not. The question
             | of platonism comes down to the definition of words like
             | "real" and "exist". It is very easy to equivocate using
             | these words, which is why most discussions about
             | mathematical platonism are so low quality. I think the
             | overall question isn't that meaningful so I'm not really a
             | platonist or an anti-platonist. In most parts of human
             | life, when I say "x exists", I mean that I can reach out
             | and touch x, that it has a mass, temperature, surface
             | texture, etc. In math, when I say "x exists" I just mean
             | that I can talk about x without creating any logical
             | contradictions. The square root of -1 may not exist in the
             | same sense as my laptop here, but it exists in the sense
             | that I can do things with it, such as add, multiply, raise
             | to powers, etc, without reaching a contradiction in my
             | formal system. So the whole "out there" thing doesn't
             | really matter. There doesn't need to be an "out there" in
             | order for me to meaningfully say that the square root of -1
             | exists.
             | 
             | I think that a lot of philosophy is like this too, when you
             | mentally zoom in really closely on a problem, it often
             | reduces to some kind of equivocation or inconsistent
             | language usage.
             | 
             | Btw I don't really consider anthropology or sociology to be
             | real intellectual disciplines, and I'm pretty on the fence
             | about psychology and economics. I realize that is an
             | unpopular opinion but I've thought about it a lot and I'm
             | pretty certain that it's correct. Aerospace engineering is
             | real because it _attaches_ to some fundamental reality,
             | namely that of the spinning fan blades, the combusting
             | fuel, etc. If you get your engineering wrong, the fan
             | blades won 't spin. Likewise, math is attached to systems
             | of axioms. When your do your math wrong, you get a
             | contradiction. Sociology and anthropology don't attach to
             | anything, they're like a closed loop, like theology. If you
             | get your anthropology wrong, nothing really happens.
        
         | nathias wrote:
         | No it isn't scientifically supported because science does not
         | include ontology and episemology as its domain. I'm not a
         | platonist, but the reasons for not being platonists are
         | philosophical.
        
         | dandanua wrote:
         | > there's no god "behind the curtain"
         | 
         | have you looked there already? :)
        
         | mjburgess wrote:
         | This view isnt "scientifically supported" because science is
         | neutral on (indeed, even presupposes) the existence of abstract
         | objects.
         | 
         | No one believes abstracta have a physical location -- they lack
         | physical properties. The claim "2 + 2 = 4" is true -- and
         | clearly not true invirute of anything anyone thinks... if we
         | kill that person (/people), it is no less true.
         | 
         | Indeed, if numbers don't exist (for example), do we suppose
         | that we can't communicate issues of quantity with other species
         | (, & possible alien life, etc. etc.) ? (If we can, what shared
         | things are we talking about when we quantify?)
         | 
         | It seems deeply implausible to say that our use of number is
         | circumstantially psychological -- any description of reality is
         | going to be indispensably quantitative --- quantity _is_ what
         | we are talkng _about_. We are not talking about ourselves.
        
           | echopurity wrote:
        
           | jhedwards wrote:
           | I've thought about this problem quite a bit and, while my
           | initial position was the same as above (math is not "real"
           | per se) I had to concede that integers are real, because
           | quantity is self-evidently real.
           | 
           | If you have four oranges, the quantity "four" is right there.
           | If you take away one of those oranges you know that the
           | result cannot be split evenly without a remaining orange
           | because of the properties of odd numbers.
           | 
           | If you cut the remaining orange in half then you get a
           | rational number, but is that self-evidently real? The halves
           | of the orange are only "halves" because we consider them in
           | relation to their origin, which we consider to be "one"
           | orange. So rational numbers necessarily involve the human
           | action of relating some quantity to a reference quantity,
           | therefore they are a higher-level abstraction built on top of
           | the fundamental physical property of quantity.
           | 
           | In the end I decided that math is based on a foundation of
           | quantity (and maybe "space" as well?) and everything else was
           | a derived abstraction. I am very curious if anyone else has a
           | good argument for other parts of math being fundamental.
        
             | viovanov wrote:
             | Does four really exist as 4? Maybe it's just 2 squared.
        
             | dagw wrote:
             | _integers are real, because quantity is self-evidently
             | real._
             | 
             | But the there are more integers than there are quantifiable
             | 'things'[1]. Are integers that are a lot larger than, say
             | the size of the power set of all fundamental particles in
             | the universe still "self-evidently real".
             | 
             | [1] Assuming a finite universe (or a finite number of
             | finite universes) and a few other things.
        
             | ajuc wrote:
             | Electromagnetic field changes are described by complex
             | numbers. So not only you need fractions, you need
             | irrational numbers and imaginary numbers to describe the
             | universe. Why is counting oranges "self-evidently real" and
             | describing electrons "kinda real"?
             | 
             | I'd argue the opposite - oranges never appear in the laws
             | of physics. They are just our description of a collection
             | of atoms sharing some pretty loosely-defined
             | characteristic. Oranges aren't perfectly equivalent to each
             | another, so whether you count 1 small and 1 big orange as 2
             | or 1.5 oranges depends on your arbitrary decision. How
             | about 1 orange and 1 hybrid species between orange and
             | grapefruit? How close you need to be to be considered
             | orange? Classes of equivalence are determined by us not by
             | the universe, and numbers are derived from that.
             | 
             | Electrons on the other hand are as undeniably real as
             | anything in this universe can be.
        
               | jhedwards wrote:
               | Quantity has real concrete measurable effects that exist
               | irrespective of the philosophical problem of
               | classification. If I have two acorns I know I can
               | potentially grow two very real trees. They are countable
               | and that directly relates to the effect they can have on
               | the world. I like to think that maybe every tree is one
               | tree, or that all trees are part of a unity of "plants",
               | but practically speaking seeds and trees are countable
               | entities no matter how I classify them.
               | 
               | If there are two planets, we can discuss philosophically
               | that one might be a "moon" and not a "planet", or in some
               | sense that the planet is "continuous" with the space dust
               | or whatever. But the existence of two distinct bodies in
               | space will still create very specific gravitational
               | fields from their interactions. Tides are different if
               | you have one vs two moon, Lagrange points etc.
               | 
               | As for electromagnetic fields, I am not smart enough to
               | make a judgement on that. They are described by complex
               | numbers, but does that mean they reflect a physical
               | embodiment of complex numbers? Or is it just that we
               | require complex numbers in order to resolve their
               | behavior into something measurable? I love to learn about
               | electricity but sadly the math is beyond my ability.
        
               | pdonis wrote:
               | _> Electromagnetic field changes are described by complex
               | numbers._
               | 
               | You can do this, but there's no need to. You can describe
               | electromagnetism using only real numbers.
               | 
               | A better argument for imaginary numbers being necessary
               | to describe the universe is quantum mechanics, since
               | quantum interference (in particular destructive
               | interference) means that two possible events that each
               | have a positive probability taken in isolation can cancel
               | each other out, implying that probabilities can combine
               | with a minus sign. And that means that probability
               | amplitudes, which are square roots of probabilities, can
               | have nonzero imaginary parts.
        
             | mettamage wrote:
             | 4 oranges are real because we have the neural architecture
             | to classify the oranges as belonging to the same group
             | according to whatever our classification criteria are.
             | 
             | What if you can't classify but only be conscious of input?
             | Kinda like being in a super dreamy state (or psychedelic
             | one). From that state of consciousness, numbers aren't real
             | but reality can be (in the psychedelic case).
             | 
             | Just brainstorming
        
             | darkscape wrote:
             | > I am very curious if anyone else has a good argument for
             | other parts of math being fundamental.
             | 
             | Groups. You can stay in your kitchen (the neutral element)
             | or go into the bedroom, then come back (inverses). In my
             | mind, this is as real as quantity.
        
         | hansbo wrote:
         | But even if you deep dive enough, there are discrete values,
         | like in Quantum Mechanics. And as long as you have discrete
         | values, you have integers, no? So integers do not seem only
         | like human models, they seem to me as something innate in the
         | universe.
        
           | helen___keller wrote:
           | Quantum mechanics is a mathematical description of the
           | behavior of the universe, so wouldn't invoking this to prove
           | mathematical objects exist be begging the question?
           | 
           | Not to say I agree with GP, but I don't think it will be so
           | easy to prove GP wrong either
        
           | dTal wrote:
           | "Discrete values" are also a human metaphor. You say there
           | are two apples on your desk? I say there is a fuzzy quantum
           | mess of probability distribution functions on your desk. "Two
           | apples" is in your mind.
        
             | nh23423fefe wrote:
             | and spin?
        
             | shusaku wrote:
             | I'm baffled that you're invoking QUANTum mechanics to
             | ascertain that discrete values don't exist. At any rate,
             | nominalism has a rich history, so I doubt these hacker news
             | comments will solve the issue...
        
           | igorkraw wrote:
           | are atoms discrete? we used to think so. we might never get a
           | better model than quantum physics and it might still be wrong
           | and fail to explain things. So there is a human idea of
           | "discrete element" that we used to apply to everything - and
           | as we look closer, it always breaks down. that doesn't mean
           | it's a useless abstraction, but it is am abstraction - a tool
           | for thought, a map, not the territory
        
         | andreareina wrote:
         | Science has nothing to do with it, rather it's a question of
         | philosophy and what we define as being real.
        
           | dTal wrote:
           | Science is "what we have evidence for". Is there evidence for
           | some abstract mathematics that we didn't invent?
        
         | throwaway17_17 wrote:
         | I agree that this view it is not popular, but I also do not
         | think that supporters often articulate their view/support well.
         | I am a hard materialist and the amount of platonic-leaning
         | discourse around the fundamentals of mathematics confuses me. I
         | do not know how so many people (typical those outside
         | philosophy and mathematical foundations) just assume a platonic
         | style view.
        
           | dTal wrote:
           | I am currently reading "Where Mathematics Comes From" by
           | George Lakoff and Rafael E. Nunez - the same Lakoff who
           | authored the seminal "Metaphors We Live By", so I have a lot
           | of time for him. At first it seems like they're just going to
           | explore the pedagogical psychology of mathematics - how
           | interesting! But then right at the end of the preface they
           | hit you with "and by the way this is all there is to it,
           | mathematical Platonism is a lie", which struck me immediately
           | as straying out of their lane. But it seems their
           | investigation into the titular question overwhelmingly led
           | them to this conclusion. The argument is pretty simple - if
           | there is a "platonic mathematics", we cannot have any direct
           | experience of it. All mathematical thought, like all thought
           | in general, is metaphorical. The predictive power of
           | mathematics in the real world is unsurprising because we
           | throw away the metaphors that don't work well.
           | 
           | I do not _like_ this conclusion. Mathematics has always been
           | something of a religion for me. But I can find no flaw with
           | the argument. From a scientific perspective, mathematics
           | bottoms out at  "what goes on in human noggins".
        
             | imbnwa wrote:
             | >The argument is pretty simple - if there is a "platonic
             | mathematics", we cannot have any direct experience of it.
             | 
             | Aside, but this is also Aristotle's exact argument against
             | Platonism in general, though when he makes it in the
             | Nichomachean Ethics he is specifically talking about
             | ethical Good (if the definition/actual taking place of the
             | Good lies in some other plane, we can't participate in it
             | so no one is or can be good), but the idea is the same even
             | when he's talking about what a soul is in De Anima.
             | Aristotle doesn't believe in 'souls' in the way we think of
             | them as religio-spiritual entities that exceed the capacity
             | of the body; a 'soul' for Aristotle _is_ the body but in a
             | way that radically challenges the idea of a body as mere
             | shell or vessel - soul is what any form of life repeats
             | doing, as a body, in order to continue being itself. It
             | should be noted that a lot of time at Aristotle 's Academy
             | was spent in Zoology, studying animals and their anatomy.
        
             | darkscape wrote:
             | I'll have to read the book, but in my mind, the (emprical)
             | study of humans and their brains doesn't shed light on the
             | metaphysical question of the nature of mathematics. What
             | they find is how humans have developed to do mathematics.
             | We could have evolved to be the way we are with or without
             | mathematics being "out there". Survival in the physical
             | world would lead us to "throw away the metaphors that don't
             | work well". At any point in time a concrete human being
             | would still be able to consider only a limited set of
             | mathematical ideas i.e. for humans "mathematics bottoms out
             | at "what goes on in human noggins"".
             | 
             | I'd say the patterns you mentioned in an earlier comment
             | are a way for math (or parts of it e.g. some integers) to
             | be "out there". If humans embody mathematics, then
             | analogously so do those patterns.
        
             | mannykannot wrote:
             | I don't think the issue has been as definitively settled as
             | you have been persuaded to think. Let's take a look at the
             | claim "if there is a 'platonic mathematics', we cannot have
             | any direct experience of it" (I realize this is probably a
             | paraphrase of a fuller argument, but it is what I have to
             | work with here.)
             | 
             | Firstly, note the word "direct" here. If it has any
             | relevance, then the authors have assumed the burden of
             | explaining either that there are only direct experiences,
             | or why indirect experiences don't count.
             | 
             | Secondly, what are the premises here? If this is supposed
             | to be axiomatic, then there is literally no reason to
             | either accept or reject it, and claims that the issue has
             | been settled are just statements of belief; otherwise, the
             | argument needs to have premises that are not begging the
             | question in some way. As it stands, this claim is not an
             | argument; it is more of an intuition pump.
             | 
             | Metaphysical discussions tend to (always?) end up as being
             | about the meaning of words like 'real' and 'true'. Whether
             | such discussions can really tell us anything about what
             | must be true is arguably the most meta question in
             | metaphysics.
        
         | tim333 wrote:
         | >all numbers are imaginary.... mathematics is an accumulated
         | edifice of metaphors designed by human brains
         | 
         | Or you can say they exist but in a different way to physical
         | reality.
         | 
         | I mean pi probably still was 3.14159... before humans evolved
         | so it's not our fault really.
         | 
         | Personally I think maths not only exists but physical reality
         | is a subset. I mean why else is there something rather than
         | nothing? Scientifically it's the only hypothesis that works for
         | that really.
        
         | mannykannot wrote:
         | > But it is the only scientifically supported one.
         | 
         | Really? What is the empirical evidence for it?
        
         | canjobear wrote:
         | Reality is that which, when you stop believing in it, doesn't
         | go away. -Philip K Dick
         | 
         | Even if you stop "believing in" math, your proofs are still
         | either correct or incorrect.
        
           | dagw wrote:
           | The proofs are only correct in as far as you believe in the
           | Axioms of mathematics that those proofs are built on. Stop
           | "believing in" the axioms and the proofs are no longer true
           | or even meaningful.
        
             | canjobear wrote:
             | But it is still the case that IF the axioms hold, THEN the
             | proofs are either valid or not.
        
               | marcosdumay wrote:
               | So it's conditional reality. Now make that fit within
               | your usual realistic philosophy...
        
               | canjobear wrote:
               | Easy. There exist contingency relationships between
               | axioms and theorems provable from those axioms.
        
               | marcosdumay wrote:
               | Oh, yeas, your proof is quite real. And it's completely
               | meaningless, being all about imaginary things.
               | 
               | It can only have any meaning if you adhere to some
               | scientific model.
               | 
               | At this point you've deviated so much from the OP
               | discussion that you could as well talk about angels
               | dancing in pinheads. Any quantification of them is as
               | real as your proof.
        
         | tasha0663 wrote:
         | You can boil down pretty much everything to "an accumulated
         | edifice of metaphors designed by human brains, for human
         | brains".
         | 
         | In the game Hearts, if you take most of the spades you lose.
         | However, if you manage to take _all the spades_ you win, and
         | they call it  "shooting the moon".
         | 
         | In a similar fashion, when you reject everything as an unreal
         | system of metaphors, Platonism "shoots the moon" by having us
         | reexamine what we thought we meant by "real" in the first
         | place.
        
       | rthomas6 wrote:
       | What finally made imaginary numbers intuitively make sense to me
       | is realizing that the number i just represents a 90 degree
       | rotation on the complex plane. That's why i*i = -1 (it's rotating
       | 180 degrees), why imaginary numbers are orthogonal to real
       | numbers, why e^ix = cos(x) + i*sin(x) makes sense, everything.
       | 
       | When you are dealing with 2 dimensions, complex numbers are a
       | kind of hack for representing both dimensions without any kind of
       | vectors or pairs or anything, just numbers.
        
       | polotics wrote:
       | Mathematicians have always sucked at naming their variables, and
       | constants, and types... This has given pundits of all ilk
       | countless opportunity to debate...
        
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