Stephen's declaration in Proteus, "You will not be master of others or their slave," suggests that he has been reading German philosophical thoughts about self-realization. Theorization of the master-slave dialectic originated with Hegel, but many later thinkers have taken it up. Nietzsche is another possible source for Stephen's thought. Although Hegel and Nietzsche were engaged in very different philosophical projects, their thoughts about masters and slaves bear interesting connections to one another, and to Joyce.
Georg Wilhelm Friedrich Hegel's The Phenomenology of Spirit (1807) introduced the binary opposition Herrschaft und Knechtschaft into the philosophical lexicon, as one aspect of the dialectical struggle between antithetical forces that defines the development of Geist (Spirit, Mind, absolute self-consciousness). The master-slave dialectic plays itself out between human beings and also within individual subjects. It is a struggle that cannot be resolved by the extinction of either master or slave: both lack full self-consciousness, because each sees elements of itself within the other. Hegel envisions a state of sublation (Aufheben) in which the exclusionary oppositions are somehow transcended, and master and slave become equals.
Nietzsche's thoughts are rather different. In The Genealogy of Morals (1887) he distinguished the "slave morality" of the Judeo-Christian tradition from the aristocratic morals of the ancient Greeks and Romans. The slave tradition advocates values such as kindness, humility, and selflessness, and is animated by resentment of the powerful, anticipating a future Judgment that will redress all the wrongs inflicted by worldly rulers. The master ethos values strength, nobility, and inherent self-worth, and makes no apologies for the exercise of power. Nietzsche billed his work as a polemic against the slave morality that he saw dominating contemporary European culture.
Gilles Deleuze argued that Hegel and Nietzsche are fundamentally opposite thinkers, but their thoughts about masters and slaves show interesting points of connection. While Nietzsche's analysis of western history seems, on its face, to simply segregate the binaries—he affirms the ancient aristocratic ideal and denigrates the modern Christian one—the truth is doubtless more complicated: "The history of mankind would be far too stupid a thing if it had not had the intellect [Geist] of the powerless injected into it" (Genealogy of Morals 1.3). This observation suggests that Nietzsche accepts the broad outlines of Hegel's dialectical view of history, in which opposites clash to produce something greater than either one.
By the same token, it could be argued that Hegel's conception of master and slave anticipates elements of Nietzsche's thought. His conception is essentially parabolic: it was inspired by his observation of actual struggles within the political sphere (chiefly the Haitian Revolution), but he used it to think about a broader range of human aspirations. If Hegel's slave is construed as a figure for mankind and the master is God, then his Aufheben names a condition in which humanity comes to realize that it controls those spiritual forces which have subjugated it. Such a reading would align Hegel with Nietzsche's conviction that mankind has moved beyond its need for a transcendent God.
Ulysses repeatedly articulates the idea that God should be understood, in Stephen's words, as "a shout in the street," inseparable from human struggles, and Joyce's use of Arnoldian historiography suggests that he saw a dialectical element in these struggles. Arnold's Hebraism and Hellenism closely resemble Nietzsche's slave morality and master morality, but he did not simply advocate for the Greek ethos. He saw it instead as one element in a relationship of antithetical, counterbalancing forces. If, as Mr. Deasy says, "All human history moves to one great goal, the manifestation of God" (it is a big "if"), then that manifestation must involve dialectical resolution of the Greek-Hebrew duality.
Certainly Stephen is engaged in some such dialectical struggle within his own psyche. He finds himself enslaved to "two masters," the external authorities of church and state, but his response is more philosophical than political. When he declares to himself that "You will not be master of others or their slave," he announces his ambition to realize personal power by transcending or sublating the binary opposition. In Circe he says, tapping his forehead, "In here it is I must kill the priest and the king," suggesting that ecclesiastical and political masters are empowered by the slave's consent.