The following excerpts are from the so-called Käseplundergebäck (Kpg), notebooks which Martin Heidegger never published and most likely never intended for publication. In them, he toys with the Husserlian method of eidetic variation but ultimately abandons Husserlian methodology when it conflicts with his own concerns about nothing.

Dating the Kpg is notoriously difficult, but AG Brötchen suggests that it marks the beginning of work that later appeared in Heidegger's Biergartens lectures. Although Pfannkuchen has argued that the fragments cited here must have been written on a Tuesday, that view is no longer widely held.

An Exercise in Phenomenology

(From Martin Heidegger, unpublished notebooks.)

Let us begin with anything-- anything at all. Now let us move to something more specific by observing that this thing is not a hairbrush. We move further: This is neither a hairbrush nor a hatstand. This is not a hairbrush, a hatstand, nor a coliope. Not a hairbrush, a hatstand...

And so on. We continue until we have denied of the thing all the possibilities except that it is a cup of coffee. You may conjecture at this stage that the object is a cup of coffee, but surely this is not the end of our enquiries. Consider now an object which is not any of the things which the prior object is not, but further is not a cup of coffee. This, you may imagine, is nothing. This shows that a cup of coffee is next to nothing in the ontological order of things, but surely there is much more (Nothing?) to be said about this (Nothing?). ...

H[usserl] may well bracket this result, but he was far too eager with his Epoche. If he brackets nothing, I differ with him and insist that we must be inquisitive enough to ask about nothing. ... Husserl is right in that the Epoche must stop at nothing.