conditions from the double viewpoint of the ahistorical, synchronic Ereignis, which is at issue in the construction, and of the epochal, diachronic Geschehen, the issue of deconstruction. One may see here an aporia comparable to that in Being and Time: in that earlier work, Heidegger set out to retrieve the question of being qua being, but he only reached the being of Dasein; likewise in the later context: the outset is the same, but again, he only reaches the being of history. The impression of an aporia vanishes however as soon as the systematic tie is seen that links the ‘event’ to the epochs. Heidegger therefore alludes to a historical-ahistorical dialectic.⁶³ It imposes a transmutation on the transcendental method such that this method can no longer yield any regulatory focal point by which philosophy becomes an edifice and reason, architectonic. The ‘very issue’ of phenomenology that Heidegger’s transcendentalism sets free is not one. It is the twofold advent of presence: the epochal institution in illo tempore and the event-like manifestation hic et nunc. This double advent determines any possible discourse on being in the later Heidegger.

Due to this double coming to presence, truth itself appears in its unsurpassable contingency. How could there remain room for one canon of truth, one ideal of truth, if the origin is so essentially polymorphous? Alētheia is the self-manifestation in which anything thinkable and livable emerges from concealment (lēthē). Whether historical or ahistorical, coming to presence is an essentially precarious a priori.⁶⁴ The modesty of such a thinking, which remains riveted to contingency, appears in what one might naively be tempted to take as the ultimate Heideggerian referent, namely, the there is understood as the origin, oriri, of being. To the traditional philosophical wonder, Why is there being rather than nothing? Heidegger answers with the simple there is. Such an answer not only flies in the face of any quest for explanation, but it amounts to an option for the fortuitous, f or the unstable. Explanations operate by recourse to some immutable referent, a cause or a condition; but to say ‘there is’ presencing amounts to espousing what is mutable in its shifting constellations.

A great many ontic origins have run our life world through the ages: “the suprasensory World, the Ideas, God, the moral Law, the authority of Reason, Progress, the Happiness of the greatest number, Culture, Civilization.”⁶⁵ They regulate a given economy, each time, and they are always replaceable in that function. The ontological concept of origin proved to be linked to the phenomenon of setting into presence. This phenomenon is twofold: setting into presence as the rise of an order that will prevail for a while in history (the deconstructive moment), and setting into presence as the ahistorical, always instantaneous emergence of presencing (the constructive moment). In the later Heidegger the guiding issue for establishing the ontological difference is: how is the origin as a historical-ahistorical happening to be understood once its ontic representations have withered away?