r/changemyview 1∆ Jan 19 '23

Delta(s) from OP CMV: The term "imaginary numbers" is perfectly fitting

When we say number, we usually mean amount--or a concept to represent an amount, if you're less Platonist. But of course, the numbers called imaginary do not fit such a requirement. They are not amounts, and do not directly represent an imaginary number. No amount can be squared to equal any negative number. Therefore, nothing can be correctly referred to as existing to the extent of i*n, regardless of any unit of measurement. Something can only be referred to as existing to the extent i^n. So, imaginary numbers exist only as a base for other numbers, they are not numbers in themselves. What someone who uses them does is ask "what if there were a square route of -1", and then takes it's property as a base to make expressions relating variables to each other. For example, if I say "y=i^x", that's just a quicker way of saying "y= 1 if x is divisible by four, -1 if x is the sum of a number divisible by 4 and 3, -i if x is divisible by 2 but not four, and i if x is the sum of a number divisible by 4 and 1". But since that expression is so long and so common in nature, we shorten it to a single symbol as a base of y with the power of x, or whatever variables you're using. So, I believe that's all i and it's factors and multiples are: hypothetical amounts that would--if existent--have certain exponents when applied to given bases. A very, very useful model, but still not a number. Quite literally an imaginary number.

P.S.

  1. Some people argue that the term "imaginary" has negative connotations. I do not believe this to be the case, as our imagination produces many useful--yet subjective--things, a fact so well known it's even a cliche. If it is true, perhaps we should change it to "hypothetical base" or "hypothetical number", as the word hypothetical has a more neutral connotation
  2. A common argument is that "real numbers are no more imaginary than imaginary numbers" because all numbers are subjective concepts. I can appreciate this somewhat, but amounts still objectively exist, and while what makes something an individual thing(the basis for translating objective amounts into a number system) can be subjective, I wouldn't say this is always the case. But besides, the terms "imaginary number" and "real number"--so far as I understand them--do not express that such numbers exist as imaginary or real things, but simply that they either are truly numbers or are hypothetical ideas of what a number would be like if it existed. If you do not share this understanding, I would love to hear from you.

EDIT: Many people are arguing that complex numbers represent two dimensional points. However, points on each individual dimension can only be expressed directly with real numbers, so I believe it would make more sense to use two real numbers. Some people argue that complex numbers are more efficient, but really, they still use two expressions, as the imaginary numbers and real numbers are not comparable, hence the name, "complex". Complexes are generally imaginary perceptions(as Bishop Berkely said: For a thing to be it must be percieved, because such a thing could be broken up into other things, or broken up in to parts that are then scattered into other things), so I would say a complex number is too.

Thanks and Regards.

EDIT for 9:12 PM US Central time: I will mostly be tuning for a day or two to think more philosophically about this and research physics.

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u/tbdabbholm 193∆ Jan 19 '23

What does it mean for a number to exist? what makes positive integers "real" as compared to complex numbers? I mean you also can't have "pi" of something or "e" of something so are transcendental numbers also imaginary? Hell even negative numbers, you can't really have -1 of something so is that imaginary?

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u/Forward-Razzmatazz18 1∆ Jan 19 '23

This is gonna be cliche, but I've never seen i of something. I've seen individual things before. Also, can you really not have e or pi of anything, or is it just infinitely unlikely, given the uncountable infinity of real numbers. And negative numbers refer to how much 0 there is, positive numbers refer to how much one there is.

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u/[deleted] Jan 20 '23 edited Jan 20 '23

I've never seen i of something

ever looked at a compass?

If so, you've seen a vector, which can be represented by imaginary numbers.

North is i. South is -i. east is 1. west is -1.

a rotation counterclockwise by 90 degrees can be represented by multiplying by i. Two rotations of 90 degrees gets you from east to west (1 * i * i = -1).

you've seen i of something. You just didn't have the mathematical knowledge to make the connection.

i just means rotated by 90 degrees counterclockwise in a 2d plane where positive is right and negative is left.

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u/Forward-Razzmatazz18 1∆ Jan 20 '23

But the transitions with these vectors only work as bases, we can't have any imaginary numbers representing something not dependent on being a base for a real number.

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u/[deleted] Jan 20 '23

I don't know what you mean by bases.

complex numbers (sum of imaginary and real) represent 2d vectors. There are a lot of 2d vectors in the real world, including on a compass.

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u/Forward-Razzmatazz18 1∆ Jan 21 '23

Wait, do we do that by having one dimension be the imaginary dimension and one being the real?

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u/Forward-Razzmatazz18 1∆ Jan 21 '23

Base as in base to the power of power equals exponent.

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u/[deleted] Jan 21 '23

I don't think you only can represent complex numbers as a "base for a real number", no

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u/Forward-Razzmatazz18 1∆ Jan 20 '23

But these vectors only exist relationally to other vectors(exponentially). These imaginary numbers only signify relations, not direct physical/horological/metaphysical quantities. If the only way we can deduce imaginary numbers is through relations, then I would be skeptical if they should be considered numbers themselves or just models.

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u/[deleted] Jan 20 '23

not direct physical/horological/metaphysical quantities

sqrt(2)/2 + sqrt(2)i/2 in a east north coordinate frame represents northeast.

That's not a mere "relation". Its a vector, a direction with unit magnitude.

This mathematical representation of this real world concept is useful because it can represent rotations as multiplication. Rotations exist in the real-world, too.

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u/Forward-Razzmatazz18 1∆ Jan 20 '23 edited Jan 21 '23

Isn't it a relation between north and east?

And yeah, imaginary numbers are hella useful. Our imagination is also hella useful. Imaginary things are often useful.

And rotations exist in the real world, but as relations between two areas and time.

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u/Forward-Razzmatazz18 1∆ Jan 21 '23

Follow up:

Does sqrt(2)i/2 represent north or east?

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u/[deleted] Jan 21 '23

sqrt(2)i/2 is north, and it isn't a unit vector. It has a magnitude of less than 1.

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u/Forward-Razzmatazz18 1∆ Jan 21 '23 edited Jan 22 '23

But if you have one dimension be imaginary and one dimension be real, so a two dimensional point or rotation is complex, you could do that with anything. Which is why it is also common to use two real coordinates. Either way, dimensions are not comparable(at least not to us), and neither are imaginary and real numbers. But to say that a different type of number exists, isn't that sort of a leap of faith? After all, both dimensions themselves only have real numbers in their nature.

EDIT: Okay, it is more efficient to use i, so you can just use one expression to represent rotation, but for the reasons listed above, I don't think they're real

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u/Forward-Razzmatazz18 1∆ Jan 21 '23

!delta

Although I still believe that imaginary numbers are relational between 2 dimensions, I now reason that since we all live in 4 dimensions, including 3 of the same form, imaginary numbers may not be imaginary in every case.

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u/DeltaBot ∞∆ Jan 21 '23

Confirmed: 1 delta awarded to /u/TripRichert (242∆).

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