[Buddhist Thought in India, p. 262 note]
The fullest and best-documented survey of dialectical systems is still my
Der Satz vom Widerspruch
contains all my later ideas without exception.
[Further Buddhist Studies, p. ix]

If they want to know
why I moved from communism to Buddhism
they may be interested in
The Psychology of Mass Propaganda
which gives the reasons. [18]
52 Letters: Edward CONZE - Herbert ELBRECHT
[06] This pamphlet
Contradiction and Reality - A Summary
is as you will see the link between
Der Satz vom Widerspruch
and the later Buddhist works.

Like Rosa Luxemburg I see socialism as the restoration of the prehistoric
innocence and brotherhood of the human race, which in her thinking appeared
as primitive communism, i.e. Ur-Kommunismus and in mine as perennial philosophy.
Our thesis was, however, against the canons of Soviet determinism and the naive
Soviet believe in the inevitability of progress […] What I had said was:
Two things may be the outcome of the breakdown of capitalism.
Decaying capitalism either results in socialism or in chaos & barbarism.
[The Memoirs of a Modern Gnostic , Part I, pp. 21-22]