Perhaps your discussion of chance and necessity would be relevant to Toshiro Uchida's observations in <http://home.mira.net/~andy/uchida3.htm> especially towards the end of that file.
Uchida makes that point that while for Hegel "Freedom is the understanding of Necessity" (an observation that was not unique to Hegel of course), for Marx the necessity imposed by Capital has to be negated in practice in order to realise freedom. Also, he associates "freedom" with the very material categories of "free time", appropriated by capital and the shortening of necessary labour-time due to the development of the productive forces under capitalism. This follows an extensive discussion of Hegel's "circle" o cause an effect. According to Uchida, for Hegel, this circle is closed, but for Marx, it is an "open circle".
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Marcuse says: "If man has learned to see and know what really is, he will act in accordance with truth. Epistemology is in-itself ethics, and ethics is epistemology" <../../marcuse/onedimen/marcuse.htm>
(I don't quite agree with him, but I would say something similar). In trying to solve the problem of knowledge we are trying to work out how to overthrow capitalism. Given that this is a practical task first and foremost, though necessarily expressed as a theoretcial task, it's resolution must be "how we must live". Our theoretical struggle can only find its resolution in this way.
I think that in how we live we express a doubtless-imperfect theory of knowledge, the "key" to the theory of knowledge is to be able to "live" it.
... for discussion.
Andy