How did Martin Buber's views change from mysticism to dialogue?

Martin Buber’s philosophical evolution involved a transition from an early focus on mysticism to a mature philosophy of dialogue. In his early period, exemplified by his 1913 work Daniel, Buber explored mystical concepts regarding the unity of human experience. However, he eventually moved away from the notion of a mystical union between humanity and God, which implies a dissolution of the individual self.1

Instead, Buber embraced the concept of encounter, which presupposes and preserves the separate existence of both parties. This shift is most famously articulated in his 1923 work, I and Thou, where he posits that the relationship between man and God—and by extension, between human beings—is defined by a direct, mutual meeting rather than a merging of essences.21

In this mature dialogical framework:
* I-Thou represents a relationship of mutual presence and fullness of being.31
* I-It represents a relationship where the other is treated as an object of thought, utility, or analysis.31

Buber maintained that while the I-It relation is necessary for survival and scientific pursuit, the I-Thou relation is essential for true spiritual and human connection.1