Philosophical idealism

In European philosophy, idealism is the counter-viewpoint to realism, which assumes the existence of a single “real world” that we all exist in, to an equal measure, at the same time. The way we actually perceive the world may, nonetheless, differ; nature and perception are not equal. Modern philosophy is mostly realistic; natural philosophy (a.k.a. physics, science) as we know it is based completely in realism.

Idealism, on the other hand, assumes reality to be formed by ideas, where an idea might be rock, flame, libervisco or death. We are presented with a projection of part of what one might call an “idea pool”. This would pretty much mean that every other person is also an idea, whereas it's thinkable that you yourself are an idea that can both perceive and be perceived, so to speak.

Of course, you can give ideas defining importance while believing in a single, solid universe. Take the sophist ?????????? (Protagoras), for example:

Man is the measure of all things: of things which are, that they are, and of things which are not, that they are not.

We have no way of knowing what he meant, but that won't bother me, I'll just make some assumptions, because, in philosophy, I can.

Picture a red beetle. Man or no man, there is really a solid molecular substance containing quite a lot of carbon that, when hit by electromagnetic radiation of a wavelength between about 400 and 700 nm, will absorb quite a lot of waves with a wavelength not between about 625 and 740 nm. Realistic science tells us that that is the case. However, we're talking of a beetle, a red beetle even. We, humans, shape the reality we perceive by giving it character, by giving it spirit. We say something is red, and it's only red because we say so, because we have the idea that it's red.

Imagine a sound. Would there be a sound if no-one was there to hear it ? Of course, the air would still move, but air moves when there's wind as well. What makes it a sound ? Simple: Man does. Without human ideas, reality is nothing.

Oh, and I don't think ?????????? would really like the various ways in which we interpret what he may or may not have said :-)