Skepticism is an important component of Socratic/Platonic reasoning, perhaps even its distinguishing part. (A later iteration of the Academy founded by Plato, an iteration which began with a shift of emphasis by its then director Arcesilaus around the middle of the 3rd Century BCE, was called in fact “The Skeptical Academy”.) It must be noted however that the root verb skeptsesthai means something more like “to conduct an investigation” than “to deny all positive assertions.” To be skeptical in the Platonic sense does mean to tease out the negative features, the defects, that haunt all honest attempts to assert what is true. But such skepticism, on discovering the dubious and defective, does not necessitate an unqualified denial. Thinking through opinion, a mode of cognition that Plato called dianoia, requires that we continue to hold the limited positive senses of assertions while remaining open to the anterior norms that make awareness of the negation possible. Opinion is an intermediate, a metaxy, between ignorance and knowledge. Participating in both, opinion always both reveals and conceals, indicates and detracts from knowledge. From the Divided Line, it is clear that as image stands to object, so in dianoia does opinion stand to truth. Both the positive anticipation and the nagging doubts are signs that witness to the true and “we have no power of thinking without signs” (C.S. Peirce).
A failure to understand a medium as a medium, a mistaking a means for an end, does enormous epistemological mischief. This failure is particularly acute when coupled with strong enforcement of the “Law of the Excluded Middle” — the “law” that claims that a proposition is either true or false simply with no third option. Descartes’ chief error is in restricting the realm of truth to those things that could be known with certainty, rejecting as false all statements that are in any way dubious. It is an error to reject as wholly false that which is in some sense true. But the realm of the excluded middle, the realm of what could be true but may not be, is a rejection of doxa as such, a rejection of the the only medium through which knowledge of the existentially vital may be approached. Although the abstract can be known with certainty, even this certainty breaks down when we attempt to apply it to the concrete world. Dianoia is a moderate position between rival errors: to reject as wholly false what is in some sense true, and to accept as uncritically true what is still open to doubt or error. Either of these stances is arbitrary and blind.
Thinking has a from-to character of the type that Michael Polanyi describes: “The subsidiaries of from-to knowing bear on a focal target, and whatever a thing bears on may be called it’s meaning. Thus the focal target on which they bear is the meaning of the subsidiaries.” (Personal Knowledge, p. 35) To look *at* the opinion without looking *through* it (the “dia-” of dianoia) is a failure to understand what it is. (Plato’s hypothesis of the Forms is often a victim of this type of misreading.) In a Platonic examination — the skepsis of an honest opinion — the misgiving/doubt that inevitably results is not a bug but a feature.
shared ignorance 
You know, what you were saying about skepticism being mistaken for “unqualified desire,” reminds me of the widespread rejection of metaphysics in both Continental and analytic traditions in the 20th century. Skeptical inquiry must take as its standard the complete object by which to both expose and reject defects that come into apprehension of the basis of standard condition.
In thh rejection of metaphysics, these philosophers took as defects integral to an as yet unnameable terrain of being that now stands as a roadblock forever guarding what we are ignorant about. I think our age takes nihilism and calls it skepticism.
An excellent comment, Jeff — if that’s your name!
I agree that the unqualified rejection of metaphysics that you speak of has been entirely too facile. Don’t you think that we all sift our experiences through at least an implicit metaphysics, whether we acknowledge it or not? It seems to me a worthwhile project to courageously attempt to state openly what our governing metaphysic is, even assuming an adequate one is impossible. Those who dismiss explicit metaphysics out of hand deny themselves the best resource available to transcend the limitations of their implicit metaphysics.
Exactly, but even worse, they have yet to properly state what they are rejecting, which puts in a purely negative relationship to knowledge.
Jeff isn’t really my name. I’m a philosophy bot:)
Often true. At the same time, when they do give a positive articulation of anti-metaphysics, the result can be quite interesting. The Continental thinkers in rebelling against metaphysics (as metanarrative, onto-theology or whatever) are really doing metaphysics a service by unmasking an idol of the same. That their position is parasitic on a (false) version of metaphysics really kind of makes my point, doesn’t it? Their next move after dismissing metaphysics is almost always to defend a position that is metaphysical in all but name.
I don’t have anything to add except the affirmation that I am recieving the best sort of education in following these threads of thought. It’s good to know my skepticism of skepticism may be better doxa than my usual doxa.
Glad my posts are helping. I have been a little slow in posting things because I am working on a draft summary of my entire argument, which I will post when its in shape. I expect to be done by the end of the month. We’ll see.