Philosophy: Martin Buber

Martin Buber, (born February 8, 1878, Vienna—died June 13, 1965, Jerusalem), German-Jewish religious philosopher, biblical translator and interpreter, and master of German prose style. Buber’s philosophy was centred on the encounter, or dialogue, of man with other beings, particularly exemplified in the relation with other men but ultimately resting on and pointing to the relation with God. This thought reached its fullest dialogical expression in Ich und Du [I and Thou] (1923).
https://www.britannica.com/biography/Martin-Buber-German-religious-philosopher
Standing out among his other work, Buber's I and Thou is a masterpiece of philosophic thought. The following excerpts are from the 1958 English translation by Ronald Gregor Smith.

TO MAN THE WORLD IS TWOFOLD, in accordance with his twofold attitude. The attitude of man is twofold, in accordance with the twofold nature of the primary words which he speaks. The primary words are not isolated words, but combined words. The one primary word is the combination I-Thou. The other primary word is the combination I-It, wherein, without a change in the primary word, one of the words He and She can replace It. Hence the I of man is also twofold. For the I of the primary word I-Thou is a different I from that of the primary word I-It.
PRIMARY WORDS DO NOT SIGNIFY THINGS, but they intimate relations. Primary words do not describe something that might exist independently of them, but being spoken they bring about existence. Primary words are spoken from the being. If Thou is said, the I of the combination I-Thou is said along with it. If It is said, the I of the combination I-It is said along with it. The primary word I-Thou can only be spoken with the whole being. The primary word I-It can never be spoken with the whole being. [...]
THE LIFE OF HUMAN BEINGS is not passed in the sphere of transitive verbs alone. It does not exist in virtue of activities alone which have some thing for their object. I perceive something. I am sensible of something. I imagine something. I will something. I feel something. I think something. The life of human beings does not consist of all this and the like alone. This and the like together establish the realm of It. But the realm of Thou has a different basis. When Thou is spoken, the speaker has no thing for his object. For where there is a thing there is another thing. Every It is bounded by others; It exists only through being bounded by others. But when Thou is spoken, there is no thing. Thou has no bounds. When Thou is spoken, the speaker has no thing; he has indeed nothing. But he takes his stand in relation. [...]
I CONSIDER A TREE. I can look on it as a picture: stiff column in a shock of light, or splash of green shot with the delicate blue and silver of the background. I can perceive it as movement: flowing veins on clinging, pressing pith, suck of the roots, breathing of the leaves, ceaseless commerce with earth and air – and the obscure growth itself. I can classify it in a species and study it as a type in its structure and mode of life. I can subdue its actual presence and form so sternly that I recognize it only as an expression of law – of the laws in accordance with which a constant opposition of forces is continually adjusted, or of those in accordance with which the component substances mingle and separate. I can dissipate it and perpetuate it in number, in pure numerical relation. In all this the tree remains my object, occupies space and time, and has its nature and constitution. It can, however, also come about, if I have both will and grace, that in considering the tree I become bound up in relation to it. The tree is now no longer It. I have been seized by the power of exclusiveness. To effect this it is not necessary for me to give up any of the ways in which I consider the tree. There is nothing from which I would have to turn my eyes away in order to see, and no knowledge that I would have to forget. Rather is everything, picture and movement, species and type, law and number, indivisibly united in this event. Every thing belonging to the tree is in this: its form and structure, its colors and chemical composition, its intercourse with the elements and with the stars, are all present in a single whole. The tree is no impression, no play of my imagination, no value depending on my mood; but it is bodied over against me and has to do with me, as I with it – only in a different way. Let no attempt be made to sap the strength from the meaning of the relation: relation is mutual. The tree will have a consciousness, then, similar to our own? Of that I have no experience. But do you wish, through seeming to succeed in it with yourself, once again to disintegrate that which cannot be disintegrated? I encounter no soul or dryad of the tree, but the tree itself.