Discourse - is the written or spoken study or investigation of a subject.
Dialectic - is finding the truth of a subject from multiple points of view.
These two concepts should hopefully form part of the basis of our learning. Now... I am by no means prolific in vocabulary or linguistics, so if anyone feels that they would like to suppliment or correct any definition or use of language they see, let us engage in dialectic and reach the truth for all of our benefit :)