Karl Marx is quoted as saying "religion is the opiate of the masses." He suggested that people were happy with their existence, no matter what its condition, because of religion.
Marx did not believe in unseen truth and identified religion as an example of such. His theories about the effects of religion suggest that following an unseen truth is paramount to superstition. He equated belief systems based on faith to a drug, where the follower has a false sense of consciousness. Marx suggested that, like an opiate, faith offered an illusion of security and safety that was based on an unknown future. Further, he believed religious people endured difficult life situations in expectation of a glorious afterlife. He theorized that the plight of the poor was not a result of God's will but rather was caused by oppression. He advocated for people to focus on the reality of their situations, which would enable them to stand up against their oppressors. Additionally, he saw the refusal to revolt as a way the religious helped perpetuate systems of inequality. Marx has been described as selfish, which could account for his inability to understand the value of religion in the lives of others.