Der Ister is a poem by Friedrich Hölderlin, the title of which refers to an ancient name for a part of the Danube River.

In 1942, in the darkest depths of World War II and the National Socialist period, Heidegger chose to deliver a lecture course on a single poem by Friedrich Hölderlin: "Der Ister," about the river Danube.

The course explored the meaning of poetry, the nature of technology, the relationship between ancient Greece and modern Germany, the essence of politics, and human dwelling.

Heidegger cites a line from Sophocles' Antigone connecting the noun and verb forms of the word, and then indicates that the sense in which Hölderlin's works are hymns must initially remain an open question.

[4] Rather than delving immediately into this question, Heidegger makes a detour, elaborating the "metaphysical interpretation of art."

The metaphysical interpretation of art relies on the distinction between the sensuous and the non-sensuous, the aesthetic and the noetic, the sensible and the intelligible.

[5] Against the metaphysical interpretation of art, Heidegger asserts that the rivers in Hölderlin's poetry are in no way symbolic images of a higher or deeper content.

[7] To understand what this means, Heidegger considers some lines from another Hölderlin poem, "Voice of the People," in which the rivers are referred to as "vanishing" and as "full of intimation."

Human activity is thought as labour, equated with mechanical energy, and assessed according to the performative principle.

"[13] Heidegger then deconstructs the concepts of space and time, arguing firstly that these cannot be merely "objects," as though they were some gigantic containers in which everything is accommodated.

Such metaphysical interpretations of space and time will be of no help in understanding the locality and journeying at the heart of Hölderlin's non-metaphysical poetising.

But it remains undecided whether this process is turning human beings into mere planetary adventurers, or whether it is the beginning of another tendency, toward new forms of settlement and resettlement.

He asserts that "one's own" is in this case the German fatherland, but immediately adds that "coming to be at home is thus a passage through the foreign."

This is why this poetry necessarily takes the form of a dialogue with foreign poets, specifically, Pindar and Sophocles.

[15] The choral ode from the Antigone of Sophocles is according to Heidegger the singular work radiating throughout the poetry of Hölderlin.

Heidegger ties this to his prior argument that human beings as poetised by Hölderlin are "unhomely" ("unheimisch"), that is, on the way toward becoming homely.

Heidegger makes clear that this being unhomely does not mean simply homelessness, wandering around, adventurousness, or lack of rootedness.

The "political" is conventionally understood in terms of consciousness, in a "technical" manner, as the way in which history is accomplished.

Heidegger uses the word Wirbel, swirl, in this context, and speaks of the polis as essentially "polar."

The pre-political essence of the polis, that which makes possible everything which we call political, is the open site from out of which all human relations toward beings are determined.

[28] Such reflections are intended by Heidegger to assist in the following gesture: the assertion that the hearth, named by the chorus, is being.

The expulsion referred to in the closing words of the choral ode is not a rejection of the unhomely, as much as an impulsion to be attentive to the homely, to risk belonging to it.

To understand this, Heidegger turns to Hölderlin's famous letter to Casimir Boehlendorff, which thematises the relations between Germany and Greece.

Despite the influence of German metaphysics, Heidegger argues that Hölderlin's use of this word was singular, as that which is alongside itself in thinking itself, and always as "communal" spirit.

What spirit thinks is that which is fittingly destined for human beings, yet this is always that which is futural, never something that has been decided; it is something "non-actual" that is already "acting."

The rivers are the children of the heavens, signs that bear sun and moon in mind, but at the same time the sons of the earth.

What the vocation of the Ister is, it well knows, but the Rhine, which does not linger at its source but departs sideways, is altogether concealed.

The unity of locality and journeying here cannot be conceived in terms of "space" and "time," for these are themselves the offspring of the realm that lets their openness spring forth.

Yet what Hölderlin means is that we must dwell poetically upon this earth, bearing and suffering it rather than forcing and seizing it.

[49] Heidegger ends with a quotation from yet another Hölderlin hymn, "The Journey": A dream it becomes for him who wouldApproach it by stealth, and punishes himWho would equal it with force.Often it surprises oneWho indeed has scarcely thought it.The lecture course formed the basis of the 2004 film The Ister.