Why did Martin Buber believe I-It relationships were sometimes necessary?

According to the German religious philosopher Martin Buber, the I-It relationship—in which beings are treated as objects of thought, tools, or conveniences—is sometimes necessary for practical purposes, such as human survival and the advancement of science.1

While Buber advocated for the I-Thou relationship as the ideal form of encounter, he recognized that human life requires navigating a world of objects and social functions. He proposed an ethical "demarcation line" that must be drawn daily: one should strive for an I-Thou relation whenever possible but settle for an I-It relation whenever it is necessary for concrete situations.1

Buber acknowledged that while he may have appeared to "wrong the It" in his writing, his focus was a response to his own era, which he felt was characterized by a "withering" of the Thou. He maintained that the I-It mode is essential for the creation of pure and applied science and for managing the practical realities of human existence.1