Was pi invented or discovered?

[Tiberius]

"Red" is not an intrinsic property of light, it's merely a way for humans to describe how our eyes perceive certain wavelengths.

But those wavelengths exist...that's my point. Just as one could argue sounds don't actually exist, but are only our ways to describe certain oscillations that reach our ears.

A wavelength is an intrinsic property of light, and we can measure it (and call different wavelengths different colors). Numbers however, are not intrinsic to anything in the universe, just as the names of colors aren't. Numbers (and names of colors) are inventions of humans to describe other things in the universe which are more abstract, like the number of cows, or what we see when a certain wavelength of light hits our retina.

"Circle" is the name of a defined surface area, which exists in the physical world. Circles have always been there, but the name for them is a human invention.

Not true, at least not when talking about mathematical circles, or circles that are defined by Pi (the exact number). What you might think of a circle in the real world, may be close to what a perfect mathematical circle might look like (compared to other things, like a square for instance), but it is nowhere near a perfect circle. Take any circle you find or construct in the real world, and zoom in. You'll see that the edges are not perfectly rounded; there are multiple imperfections, and if you measured the circumference and divided by the diameter, you would never get close to Pi.

Bolded and italicized the important bit, in other words it's not. No more than 1 is an intrinsic property of a single cow, for us. Unless you're okay with 1 being a property of a cow, I'm not okay with red being a property of light.

Red isn't a property of light; I don't think I ever claimed it was. I said it was the name of a color. I probably could have been more accurate and said it was the name of our interpretation of a wavelength of light, but that's the definition of a color anyway!

Because math doesn't exist in the real world /thread...... A mathematical object that describes a defined area. Tell me, Arac, what is preventing such a circle from existing anywhere there is space to be defined into areas?

"I can't draw one with my pencil therefore they don't exist"

What is preventing such a circle from existing? I went over that in my first post. A perfect circle requires Pi to be irrational; a non-repeating infinitely long number. Such numbers cannot exist in the real world, given their properties which do not exist in the real world. Additionally, a perfect circle would have to have an infinite number of points on it, each one the same distance from the origin. An infinite number of points would require an infinite amount of space and matter, which we simply don't have. So no, you can't have one anywhere in the universe. They exist only in mathematics.