And we find ourselves at the end, just after the rocky-horror like force of the “pleural shock,” quoting Thomas Mann, 

I know death .. I can tell you it’s almost nothing … We come out of the dark and go into the dark….   

Sloterdijk, Critique of Cynical Reason, p. 529. Simon Critchley took this to title one of his books. 

Mann’s reflection on life and death is also made by Nietzsche who speaks of the human being as a rope suspended over an abyss, between animal and Übermensch (Nietzsche, ZI, Prologue §4).  — Elsewhere I emphasize that it has already been noted that it it is important to note that the term corresponds to Lucian’s hyperanthropos. 

Hence Zarathustra’s Lucianic Übermensch refers to the Afterworld and to the human who is dispossessed not only in this world, as Sloterdjk rightly read Heidegger as saying, but is similarly ill at ease and not at home in the world to come, Nietzsche also calls the human being, using two dashes or Gedankenstriche as punctuation “— a hiatus between two nothingness [zwei Nichtsen] —“ (KSA 12, 473)

Thus we might undertake to read philosophy in a sense that engages what “Philosophy demands as life,” conceived as Sloterdijk conceives it via Thales, “’as what is difficult’, to know thyself.” (CCR, 536) 
Now Sloterdijk is able to see not only the popular joke with Thales and the Milesian maid (but we have already noted such proclivities as par for the philosophical course) but and indeed that for Thales both theoretical and practical regards can coexist.
Rather than being dissonant as today’s renaissance of re-reading of Anaximander seem to insist, this goes hand in glove with readings of Empedocles that would strip his Katharmoi of any cathartic or purifying force.   
All in service of the preludes of science they say. 

But ‘know thyself” works dialectically in an extraordinary way to make such sundering readings redundant: “for Thales, knowledge of the heavens and self-investigation could proceed directly parallel to each other.” (537) 

Sloterdijk ends here in a fashion both Heideggerian and kynical, precisely in Diogenes’ spirit.  For Sloterdijk in its self-incurred tutelage or blinding,

practical reason could not see that the highest concept of behaviour is not “doing” but “letting things be,” and that it achieves its utmost not by reconstructing the structures of our doing but by penetrating the relations between doing and desisting.  Every active deed is etched in the matrix of passivity; every act of disposing over something remains dependent on the stable massiveness of what is not at our disposal; every change is borne also by the reliable perseverance of what is unchanged; and everything that is calculated rests on the indispensable base of what is predictable. (540) 

    
This is the problem of lying even for moral reasons. For Kant as for Sloterdijk, “those who can let things be are not pursued from behind by projects that have taken on a life of their own.” (531) 

And in that sense “the great thinking of antiquity is rooted in the experience of enthusiastic tranquility when, on the summit of having-thought, the thinker steps aside and lets himself be permeated by the self-revelation of the truth.” (Ibid.) And Sloterdijk quotes Heidegger to say this, as the logos that “lets itself ‘be given to think’ what is thinkable by being itself.” (Ibid.) At the end, it becomes earnest for Sloterdijk, with his allusion to the golden, Goethian “present” that we have earlier already referred to, here not heavy or deadly earnest, rather of a “courage” born of the experience of a well-spent life, the courage of Kant’s daring in his Sapere aude, a courage that 

“can suddenly make itself felt as a euphoric clarity or a seriousness that is wonderfully tranquil within itself. It awakens the present within us. In the present, awareness  climbs all at once to the heights of being. Cool and bright, every moment enters its space: you are no difference from its brightness, its coolness, its jubilation.”  (547)   

This feeling which Nietzsche for his part called “the happiness of a god, full of power and love, full of laughter and full of tears,” is also a benediction.