In The German Ideology Marx and Engels contrast their materialist method with the idealist philosophy that was popular in German thought. Materialism argues that the sensuous, material world has a reality independent of the mind or the spirit. The world that is perceptible to the senses—the world of touch, taste, sight, and sensation—is where ideas emerge. Materialism contrasts idealism, which argues that matter is dependent on the mind or the spirit.

The use of these terms differs from their everyday usage. For example, idealism is associated with virtue and high-minded ideas, whereas materialism has connotations of greed and commercialism. In philosophy materialism focuses on matter and the physical world, while idealism is concerned with ideas.

Hegel’s idealism emphasizes the human subject but is interested in thought or contemplation. Idealism argues that the world is created through the mental categories we use to understand it or impose upon it. Change occurs through the transformation of the spirit or the mind, which then realizes itself in society or the material world. Marx and Engels spend a significant portion of the book responding to Stirner because he pushes the idealist argument to its furthest point. Stirner writes, “Concepts should play the decisive role everywhere, concepts should regulate life, concepts should rule.