Imaginary numbers are inherently unobservable

In summary: There is no displacement in our space that is modeled by a complex number. This is why they have a slightly different status."
  • #1
madness
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Maybe this should be in the philosophy of science/math forum, but i thought it fitted here. Why is it that variables taking imaginary values are inherently unobservable, whereas real numbered variables correspond to observables like position/momentum? As far as I can see there is no a priori reason why this should be the case.
 
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  • #3
Thanks that's an interesting thread. Here is a more specific question to explain what i mean. Why is it that Hermitian operators in quantum mechanics (ones with real eigenvalues) correspond to observables. What is it about real numbers over complex ones that make them observable? I don't think this question was directly covered in that thread.
 
  • #4
Well, ultimately everything boils down to measurements of position: whether it's where the pointer is pointing to, or which LEDs are lit etc. The Ancient Greeks discovered (much to their dismay) that irrational numbers are realized in nature (e.g. the right-angled triangle with the two smaller unit sides has a hypotenuse of irrational length).

And so it was known, that the set of real numbers were realized in nature. There is no displacement in our space that is modeled by a complex number: this is why they have a slightly different status.
 
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  • #5
masudr said:
Well, ultimately everything boils down to measurements of position: whether it's where the pointer is pointing to, or which LEDs are lit etc. The Ancient Greeks discovered (much to their dismay) that irrational numbers are realized in nature (e.g. the right-angled triangle with the two smaller unit sides has a hypotenuse of irrational length).

And so it was known, that the set of real numbers were realized in nature. There is no displacement in our space that is modeled by a complex number: this is why they have a slightly different status.

thank you for saying here about what it was that i was trying to say in the other thread (that got so contentious). i would say it as "the set of numbers are realized quantities in nature are called "real numbers".
 

Related to Imaginary numbers are inherently unobservable

What are imaginary numbers?

Imaginary numbers are numbers that can be expressed as a multiple of the imaginary unit, denoted by the letter "i". The imaginary unit is defined as the square root of -1.

Why are imaginary numbers considered unobservable?

Imaginary numbers are considered unobservable because they do not have a physical representation in the real world. They are purely conceptual and cannot be measured or observed directly.

How are imaginary numbers used in science?

Imaginary numbers are commonly used in science and mathematics to solve problems that involve complex equations and have no real solutions. They are also used in fields such as engineering, physics, and economics.

Can imaginary numbers have real-world applications?

Yes, imaginary numbers do have real-world applications. They are used in a variety of fields such as signal processing, quantum mechanics, and electrical engineering. They also have applications in finance and economics, for example in modeling stock market fluctuations.

What is the difference between imaginary and complex numbers?

Complex numbers are numbers that have both a real and imaginary component, while imaginary numbers are solely composed of the imaginary unit. Complex numbers have both a real and imaginary axis on a graph, while imaginary numbers only exist on the imaginary axis.

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