Quote Originally Posted by stormcrow View Post
Yes I suppose if I did not exist in this hypothetical world then my concept of "good" would count for nothing because I do not exist. I was leaning too strictly on Plato's idea of the forms because he believed that the"good" was an universal quality of the world as well as the source of all knowledge. I didn't really take as much time as I would have liked to distinguish my ideas from his in this thread. So if there was no wavelength of purple would we not be able to perceive it? I think the existence of a possible skyscraper is a bit different from the possibility of purple given that red and blue both exist. I think because since it is possible for purple to be derivative from red and blue it has a kind of more concrete ontological existence than a potential skyscraper. But I do conflate possibility and actuality these days so I don't know if that conclusion is logically sound.
If there are humans, such as us, capable of perceiving purple light, but such light does not exist, then not only do they not perceive it, but that light still does not exist. Again, they might one day create purple light, or that light might come into existence through random chance. But it does not exist. Just like we might one day perceive a skyscraper or new mountain (which can derive from steel, concrete, and the slow tectonic forces of the earth). We are capable of perceiving it, but that capability does not mean such things exist (yet).