Idealism is the philosophical belief that the universe operates either in a way that is similar to our thoughts, or is composed of thoughts itself.

A transcendental or pragmatic idealism suggests that the mechanism of the universe is similar to thoughts, and we know it through the metaphor of thoughts (as we cannot perceive it directly, and know it only through our perceptual filter) but that, in our lives as functional beings, what becomes important is not the tangible, physical world but its significance, or meaning, in the context of thoughts.

An easy example would be the heroism of soldiers going into battle. Their losses matter, but ultimately what is most important is that a principle is upheld: the nation defends itself, or one type of philosophy stands above others.

Still going further, idealism works around our fear of the world ending when we do. We are beings imbued with a life-force, but what makes us ourselves is mostly contextual, with the will to live and the ability to have consciousness being part of the world as idea, not the representation upon which we base all of our decisions and in which we live.

In a modern society, there is little use for idealism. It cannot make you rich or famous. Maybe it rests your mind however.