Eugen Rosenstock-Huessy (1888–1973), German social philosopher

Along with Franz Rosenzweig, Ferdinand Ebner, and Martin Buber, Rosenstock-Huessy is a major contributor to "speech thinking," and it is a central concern of several works of his, perhaps the most important, in English, being Speech and Reality. The basic idea of “speech thinking” is that our reality is not only an object to be espied, but an extension of our powers. And of all the powers which constitute us, it is speech, with its calls and responses, vocatives and imperatives, solicitations and appeals, that enables us to undertake collective action and thereby transform ourselves and the world around us. Speech does not merely describe or denote what exists, it enables us to draw out from ourselves possibilities and realities which are yet unrealized.

In place of Descartes’ "I think therefore I am," which is the clarion call to become lords and masters over nature and thereby to treat nature as a great machine subject to our will and our cognitive capacities, Rosenstock-Huessy taught "I respond, although I will be changed." This is a formulation, which comes from the recognition that life calls us into ever-fresh tasks and that we never approach urgent things already in full knowledge of an outcome. Being open to speech is being open to the various insights and requests, the urgencies and necessities that are encapsulated in speech. It is the recognition that we are mutual creators of each other and the world around us; that is a reality we cannot avoid, though we can easily fail to see what it involves. That our words become flesh is, in fact a variant of another fact—that we dissolve and resolve again in acts of love. Speech thinking, in other words, stands in the closest relationship to the law of love.