Ludwig Feuerbach (1804-1872) was a German philosopher and major theologian.

During his early years, Feuerbach belonged to the "Young Hegelians"- a group formed by intellectuals during the 1830s, who inspired by Georg Wilhelm Friedrich Hegel’s philosophy, engaged on radical political criticism against the Prussian state and the foundations of Christian religion. Although Feuerbach was initially a supporter and follower of Hegelian thought, he eventually turned against Hegel to develop a materialist philosophical doctrine. His argument shifted from Hegelian reasoning that centered on idealist abstractions towards an anthropological approach that places nature and human beings at the core of the analyses. Ideas are a reflection of the material reality.

Whereas Hegel asserted that thought proceeds material relationships, Feuerbach believed that thought proceeds from being itself. Hegel's conception reseted on the Cartesian idealist individualism, 'I think therefore I am.' Feuerbach situated human consciousness within the particular circumstances of individual existence. Karl Mark rejected both of these ideas as one-sided formulations, neither of which were valid. Feuerbach was an important step in moving away from abstract idealist notions of spirit and mind as universal categories. Marx took this even further grounding the very notion of species into his term 'species-being.' 

In his major works, The Essence of Christianity (1841) and Lectures on the Essence of Religion (1851), Feuerbach scrutinized Christian philosophy to prove that religion is an alienating force, inherently human in origin. He argues that God is merely a reflection of man. Man is a purely biological being that exists before society. Human beings create thoughts, culture, and thus, they create God. This notion fundamentally opposes traditional Christian beliefs, which emphasize man’s dependency on a Supreme Being to exist. Feuerbach asserted that religion itself is “nothing but the essence of human being.” This omnipotent being represents the ideals, qualities or attributes that human beings believe can never achieve. By projecting their self-imposed limitations on a Divine Power, human beings are unable to achieve their own potential self and, thus, they are unable to historically progress. We pray for the things that we don't have to a power that contains all the characteristics we idealize, but also don't possess. God becomes what we see as a solution to our alienation, but religion preserves social relationships that perpetuate the alienation of humankind.

The very religions that preach brotherhood and to love thy neighbor establish strong boundaries of identity that separates human beings and perpetuate violence. Even the act of calling oneself a Christian or a Muslim creates a divide between two people and defines their relationship to each other within a form of difference. Feuerbach argued for a new version of humanism centered around love to replace the alienating system of religion. He saw love as the true union of self and other. Through the power of love boundaries can be overcome and individuals can care for themselves and each other through an emotion that they themselves are capable of. Instead of praying to God for love we can learn to love each other and ourselves in a way that brings us together. 

Feuerbach’s writings strongly influenced on Karl-Marx and Engels. Both took Feuerbach’s critical perspective on religion and Hegel as a significant contribution, and as a starting point towards the development of a more complex theory of historical materialism. Marx’s Theses on Feuerbach, expanded the theory of alienation on religion and applied it to human labor.