Rather, it is “what originally makes everything possible,” analogous to the Good in Plato.¹⁶²

We will never get an answer to the question “What possibilizes that which possibilizes everything?” Even to ask that question is a fool’s errand insofar as it traps us in a petitio principii, a begging of the question—in this case, not realizing that we are already wrapped up from the outset in what we are attempting to find.¹⁶³ Heidegger does say that “the petere principium, the reaching out to the supporting ground, is the only move that philosophy ever makes.”¹⁶⁴ But what he means is that true philosophical thinking actively presupposes the presupposition by electing to leave it in its unknowability rather than trying to question behind it. Thus, to seek the ultimate basis for intelligibility already presupposes the ultimate basis for intelligibility and thus is caught in circular reasoning.¹⁶⁵ Everything is knowable except the reason why everything is knowable.¹⁶⁶ The unknowability of the why and wherefore of our thrown-openness as the clearing is what Heidegger finally means by “facticity,” now reread as the mystery.

With Heidegger’s lecture “On the Essence of Truth” the door opens on to the later Heidegger. By December of 1930 he had the wherewithal to begin working out what he had projected for SZ I.3 but had been unable to finish. He could now take up “the thing itself” outside the Procrustean bed of transcendentalism. It would take him a few more years to settle into the new approach that would shape his work for the next four decades, but at last the way was clear. The transition to the clearing, which he had originally programmed into Being and Time, would henceforth be absorbed into the changed perspective of the 1930s that issued in his seinsgeschichtlich approach.

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The issues we have discussed in this chapter were among the many obstacles that hindered Heidegger’s efforts to complete SZ I within a transcendental

162. GA 22: 106.32 = 87.32: “Alles ursprünglich ermöglichend.” Thus, too, Plotinus, Enneads VI 9: 11.2–3, οὐκ ἔκφορον ἐκεῖνο ὄν: The Good cannot be “brought out” or disclosed. Ibid., VI 7: 40.51–52: ᾧ δὲ μήτε τι ἄλλο πρὸ αὐτοῦ: that before which there is nothing. GA 34: 78.6 = 57.22: “daß das Wesentliche immer unbeweisbar bleibt.”
163. Begging the question: Aristotle, Prior Analytics II 16, 64b28–65a9: τὸ ἐν ἀρχῇ αἰτεισθαι καὶ λαμβαίνειν (“Petere et sumere quod ab initio quaesitum fuit,” Bekker III, 35a32.)
164. GA 9: 244.32–33 = 187.28–29.
165. Circular reasoning, τὸ κύκλῳ δείκνυσθαι: Prior Analytics II 5, 57b18–59b1.
166. See above, note 16.