Fromm was raised as an Orthodox Jew and, although he later gave up religious observances, he never gave up the belief that religious teachings contained some basic truths about human nature and never shared Freud's ideas that religion is only an illusion and an expression of the human wish for a protecting father-figure.
Fromm did, however, adopt some of the American views of Freud which regarded psychotherapy as a good means for releasing human creativity and transforming some of the negative aspects of American life. He also worked on synthesizing the works of both Sigmund Freud and Karl Marx:
"I wanted to understand the laws that govern the life of the individual man, and the laws of society-that is, of men in their social existence. I tried to see the lasting truth in Freud's concepts as against those assumptions which were in need of revision.
I tried to do the same with Marx's theory, and finally I tried to arrive at a synthesis which followed from the understanding and the criticism of both thinkers."
Fromm's work can be divided into four general themes: the ways in which psychoanalysis can help us understand individual motivations in social and economic circumstances, his revisions of Freud's ideas about psychoanalysis, his critiques of modern industrial society, and finally his analysis of how religion affects human development.
Unlike some researchers, Fromm did not idealize or romanticize religion. He understood that it can have many drawbacks and, as a result, Fromm differentiated between those religions which could be characterized as authoritarian and infantalizing and those religions which were, in contrast, humanistic and liberating.
For Fromm, the goal of a truly humanistic religion should be to help humans overcome greed, hate, arrogance, and egocentrism. According to Fromm:
"Mental health, in the humanistic sense, is characterized by the ability to love and to create, by the emergence from the incestuous ties to family and nature, by a sense of identity based on one's experience of self as the subject and agent of one's powers, by the grasp of reality inside and outside of ourselves - that is, by the development of objectivity and reason. The aim of life is to live it intensely, to be fully born, to be fully awake.
To emerge from the ideas of infantile grandiosity into the conviction of one's real though limited strength; to be able to accept the paradox that everyone of us is the most important thing there is in the universe - and at the same time no more important than a fly or a blade of grass."
In 1975 Erich Fromm wrote an open letter to humanistic Christians in an attempt to get them to understand the importance of how people relate to each other and to society:
"Idolatry is not the worship of certain gods instead of others, or of one God instead of many. It is a human attitude, that of the reification of all that is alive. It is a man's submission to things, his self-negation as a living, open, ego-transcending being. ...
The modern concept of alienation expresses the same idea as the traditional concept of idolatry. The alienated man bows down to the work of his own hands and the circumstances of his own doing. ...
Today's idols are the objects of a systematically cultivated greed: for money, power, lust, glory, food, drink. Man worships the means and ends of this greed: production, consumption, military might, business, the state.
The stronger he makes his idol, the poorer he becomes, the emptier he feels. Instead of joy he seeks thrills, instead of life, he loves a mechanized world of gadgets, intead of growth he seeks wealth, instead of being he is interested in having and using."