Buber’s I and Thou begins differentiating between the I-It and the I-You, which can be partly mapped onto third person and second person relationships, or talking-about and talking-to. One might be inclined to think that there should be a ‘another’ word, one that corresponds to the first person. There isn’t.
Let’s say we begin on the upper floor of language, the third person, or the I-It. Here things are talked-about, signs function as Peircean thirds, in that an interpretant connects a sign to an object, language operates like a network, comparing, contrasting, connecting, interpreting, networking, mediating.
We decend one level to the second floor, closer to the foundation, the I-You, or second person. Here relationships have two terms: me and you, nothing else or no one else determines the relationship. There is no network, no comparison, no positioning, no mediation. What lies beneath?
What differentiates Buber from many other thinkers with a similar ‘mystical’ tone is that (after Daniel at least) there is no ‘first person’ floor, no I-I, no mystical unifying ecstacy. As is well known, the ‘first person’, or I, is always linked to an object, and the object determines the contours, or composition, of the I. The I-You floor is the ground floor.
But that doesn’t mean there is nothing below, just no ‘I’: in the basement of Buber’s house, there are no individuals, there are only firsts, affects, relations with only a single term: circulating feelings thoughts, and sensations.
 Wolfson, Unity, 423
 “For the I of the basic word I-You is different from that in the basic word I-It.”