A doctoral dissertation on the nature of human reason as a universal, species-wide capacity
What the Work Is
De ratione una, universali, infinita (The One, Universal, and Infinite Reason) is the inaugural dissertation of Ludwig Feuerbach, submitted in 1828 at the University of Erlangen, where he earned his doctoral degree. Written in Latin, the work represents Feuerbach’s earliest philosophical statement, composed while he was still firmly within the orbit of Hegelian thought. It stands as a document of orthodox Hegelianism, exalting the self-sufficiency of reason and exploring the dialectical structure of human consciousness.
What the Book Is About
The dissertation argues that the essence of humanity is Reason, understood not as an individual possession but as a universal and infinite “species-essence.” Feuerbach’s central concern is the relationship between the individual self and the other—the I and the Thou—and how thinking itself enables the individual to transcend finite individuality and achieve identity with the broader human species. The work is fundamentally an exploration of how universal rationality operates through particular human beings, and how the act of thought connects each person to the collective essence of humanity.
Key Ideas and Themes
The dissertation develops a dialectical account of consciousness in which the individual, through thinking, recognizes the self in the other. This recognition is not merely an interpersonal encounter but a realization of participation in the universal essence of humanity. Feuerbach maintains a sharp distinction between thinking and sensing: communication and universality belong exclusively to the realm of thought, which he characterizes as the “being of universality,” while sense experience remains private, incommunicable, and tied to finite individuality. The I–Thou relationship is thus a dialectic within thought itself, where the self differentiates itself from the other and then recognizes its identity with it as a species-I.
The only point of divergence from Hegel in this early work concerns Christianity. Feuerbach held that Christianity could not be the perfect religion, reserving that status for “the real idea and existing reason.” This qualification, though modest, hints at the critical trajectory his thought would later take.
Significance and Influence
The dissertation is significant primarily as a foundational document for concepts that would define Feuerbach’s mature philosophy. The notions of species-being and the I–Thou relationship, which appear here in embryonic form, would later be transformed and grounded not in abstract Reason but in concrete, sensuous existence. While the work itself is an exercise in orthodox Hegelianism, it contains the seeds of Feuerbach’s later anthropological turn—the move that would eventually lead him to argue that theology must be transformed into anthropology and that the true subject of philosophy is not the Absolute but the living, concrete human being.
The dissertation was submitted in 1828 at the University of Erlangen, where Feuerbach had continued his studies after leaving Berlin. His move to Erlangen was necessitated by financial difficulties after a year of studying under Hegel. At Erlangen, he pursued philosophy and planned to study the natural sciences, attending lectures in physiology and anatomy. Following the completion of his doctorate, Feuerbach worked as a docent at the University of Erlangen from 1829 to 1835, lecturing on the history of modern philosophy. This academic position was short-lived, as his career was permanently derailed by the anonymous 1830 publication of Thoughts on Death and Immortality, an attack on the concept of personal immortality that was deemed scandalous and led to his being barred from university posts.
The Dissertation’s Place in Feuerbach’s Philosophical Development
The dissertation represents the earliest phase of Feuerbach’s thought, a period of orthodox Hegelianism that predates his later critical stance. His subsequent philosophical trajectory involved a sustained critique of the very idealism he exalted in this work. In his later philosophy, Feuerbach would argue that traditional philosophy, including Hegel’s speculative idealism, was a form of esoteric theology that abstracted human characteristics and projected them onto a divine or metaphysical being. His project became to “rehumanize” philosophy by revealing that its true subject is not God or the Absolute, but living, concrete human beings. The concepts of species-being and the I–Thou relationship, which appear in the dissertation in embryonic form within the realm of abstract Reason, would later be grounded in concrete, sensuous existence. This later shift was part of a broader movement in his thought that saw him develop a “bipolar” theory of religion, moving away from the internal projection of human consciousness to a model grounded in the human confrontation with nature.
