Volume 23 of the Heidegger Gesamtausgabe (GA) arrived by itself; probably it did not fit into the 5 kilo parcels. It belongs to the II. Abteilung of the GA, the Vorlesungen or lectures of 1919-1944, and bears the title "Geschichte der Philosophie von Thomas von Aquin bis Kant" - History of Philosophy from Thomas Aquinas to Kant. Given at Marburg, Winter Semester of 1926-27. Edited by Helmuth Vetter. [The H GA are far less impressive than the Lonergan CWL, for reasons outlined by Theodore Kisiel: the over-possessiveness of the Heidegger heirs, from what I remember. The scholarly apparatus is meagre for a German production, for example. Pity. Still, the GA run into some 90 volumes. Quite an achievement. But of course the financial potential here is enormous, given H's vast popularity in comparison with L's.]
Somehow I began reading, perhaps because of the curious fact of finding Heidegger actually speaking of Thomas Aquinas. The volume consists of a transcription of Heidegger's handwritten notes for lectures - which, from what I gather, were a job he had to do, taking time out from the printing of Being and Time. Still, they are Heidegger's notes, not just anybody's notes for lectures.
Since they are handwritten notes for lectures, they are in the form of jottings, rather than complete sentences. But: far easier to read (so far) than Being and Time, for example.
The chief contention seems to be: don't take Modern (Western) Philosophy as a completely new beginning. Its roots go back to Ancient Philosophy, but passing especially through the Middle Ages.
In the Middle Ages, interestingly, Heidegger chooses to concentrate on Thomas Aquinas. He gives the reason for this: Thomas Aquinas was a careful interpreter of Aristotle. (I was surprised to see the respect H has for Aquinas.)
Still, the main criticism is there: the forgetfulness of Being. Thomas - like everyone else - concentrated on beings - the world, the human being (psyche - Mensch), God.
The blurb on the inner covers says that these lectures were given during the last phase of the writing of Being and Time.
So H does not begin from Descartes, but goes back to Thomas Aquinas, and through Thomas, I guess, to Aristotle. He speaks of the Modern period as the Protestantism of the spirit / reason, and of the period before that as the Catholicism of the spirit / reason. He also speaks of the whole process as culminating in Hegel. (I must remember that it is Heidegger who is writing; so the great process of the overcoming of Hegel, which took place in large part also due to Heidegger, has not yet happened.) Hegel, H says, is the culmination and perfection of the development of Western philosophy. (I need to study Hegel!)
At any rate, I am thrilled to be actually reading this stuff. I have been extremely bored these days, and this has brought some life. Who knows where it will lead. I have the idea that H is struggling with a new language for Christian theology, or for religion, as well as a new language for 'philosophy.' That is, in part, also the endeavour of Lonergan. So. Let's see where this goes. A bit of cross-fertilization will not do harm. Otherwise I spend time merely on novels. Historical ones, cultural ones, of course. And perhaps not ultimately useless. But.
And: one has to read. Slowly. One has to think. And that calls for a contemplative, chewy type of reading. Mastication. Letting the juices mix.