Buber begins with a grammatical observation: there are two basic words — not words that describe but words that constitute a way of being. I-Thou is not a statement about two things but the expression of a whole mode of existence in which I and Thou constitute one another in genuine encounter. I-It is equally constitutive but of a different mode: the mode of experience, observation, use, and analysis in which the world is arranged as a collection of objects for a subject.
In the I-Thou relation, the other is met not as a bundle of qualities, functions, or instruments but as a whole, irreducible presence. I do not experience the Thou — experiencing already objectifies — I meet the Thou in direct, unmediated encounter. The Thou cannot be sought, planned, or arranged: it happens. And in the moment of meeting, both I and Thou are transformed: the I of I-Thou is not the same I as the I of I-It.
Buber does not condemn the I-It relation: it is necessary for practical life, for science, for knowledge, for the organisation of the world. What he resists is the elevation of I-It to the only valid mode of relation — the reduction of all reality to what can be experienced, measured, and used. Every Thou, the moment the encounter passes, becomes an It. The tragedy is not the passage from Thou to It but the inability to return from It to Thou.
I and Thou was originally published in German as Ich und Du (1923); the influential English translation by Ronald Gregor Smith appeared in 1937, and Walter Kaufmann's translation in 1970.
