We do not know everything. In fact, there are lots of things we can never know. So, how can we recognize the limits of our capacity for knowledge? What role might skepticism and the method of doubt play in helping us to delineate our limits? How do we know when to keep trying to figure something out and when it is better to give up and stop wasting our time?
Although we are in pursuit of an abstract distinction here, practical examples may help us to draw it more clearly. The responses will arise pretty naturally, as we lend our individual opinions to the project of discovering a shared understanding of our epistemological limits.
In the legal process, there is an aphorism which states, "I only know what I can prove in court." That may very well be a sound basis from which to begin the study of knowledge and how our own cognitive blind spots limit that study.
Plato asserted that in order for something to be considered "knowledge" it had to be justified, true and believed.
Robert Nozick argued that "knowledge" is not synonymous with "truth" but that it does 'track' with what is true.
Popper asserted that knowledge (in the form of a proof [of a theory]), must be arguable, testable and repeatable.
But what of ...
This solution discusses the differentiation between knowledge and opinion.