Thought, I think - and this is why I don’t think there can be thought beyond language - consists precisely in the separation of experience into an experiencer and an experienced (subject and content, to speak with Nietzsche). That is, Becoming - experience - requires the idea of Being; and this is what that strange fragment of Heidegger’s was about. Two sentences earlier, he says the following:
“Creation needs what is fixed, first, in order to overcome it, and second, in order to have something that has yet to be fixated, something that enables the creative to advance beyond itself and be transfigured. The essence of being is Becoming, but what becomes is and has Being only in creative transfiguration.”
http://www.escapefromwatchtower.com/heidegger.nietzsche.html
So thought is precisely this creative transfiguration of Becoming. Consciousness requires a Being beyond Becoming, an experiencer beyond what is experienced; not that this Being, this subject, really exists - for it is not an object of experience -, but in order to mirror Becoming and give the experience substance. Becoming - experience - requires the idea of Being - substance - in order to be self-conscious; not in order to be conscious. Consciousness, as most animals have it, is what I call direct experience. But, paradoxically, precisely because man is self-conscious is he not being, but becoming: he is striving, struggling, i.e., consciously striving and struggling. The un-self-conscious animal is itself strive and struggle, whereas the human animal is apart of the striving and struggling - a striving and struggling part, a striver and a struggler. Nirvana or whatever is precisely the state of mind in which there is no longer the idea of substance: in which there is no feeling of struggle and also, therefore, no thought.
“How does the perspective sphere and error come about [entsteht]? Insofar as, by virtue of an organic being [Wesen], not a being, but struggle itself wants to preserve itself, wants to grow and be conscious.
That which we call “consciousness” and “spirit” [Geist] is only a means and an instrument by virtue of which not a subject, but a struggle wants to preserve itself.”
[Nietzsche, Nachlass.]
This explains the paradox I formulated above. It remains to be seen, then, in how far Nirvana and the like are means for the struggle - “Becoming” - to grow even more. It may be the only way, for the struggle cannot grow indefinitely by means of the idea of the subject - as I have shown with my “mad God” experiment. My fear of being absolutely alone was precisely the feeling of the struggle being extinguished.