This is the long-waited thread that I promised to @Bitter Crank here:
http://thephilosophyforum.com/discussion/278/do-we-have-a-right-to-sex/p3

The question is: how do we come to correct premises? And what role does epistemology, method, etc. have in this? The short answer: none - "given any rule, however fundamental [...] there are circumstances when it is advisable not only to ignore the rule, but to adopt its opposite [...] anything goes" (P. Feyerabend - Against Method).

The texts below approach the same point from many different directions:

"Modern philosophy has been obsessed with epistemology [...] but a philosophy is and must be more than its epistemology. One can always ask what is the value of knowledge, and how it is to be ranked in the order of valuable things. This is not an epistemological question, and presupposed in every theory of knowledge, whether recognised or not, is some view of the worth of knowledge and its rank in the order of value [...] [Epistemological theories] move against a deep background of beliefs about the worth of knowledge in a wider scheme of things. As such, epistemologies have an ideological and rhetorical dimension (emphasis mine) [...] the true home of empiricism is the late nineteenth century and our own time, where it is a theory of knowledge at the service of an ideology of perpetual progress through science, technology and democracy. It is a militant ideology, resolutely forward-looking and hostile not only to religious tradition but to all traditions (emphasis mine) [...] The great transformation of the meanings of men and things brought on by the industrial revolution, and in which empiricism finds its natural home, makes no appearance in Hume's philosophy (@Sapientia) [...] It is not a philosophy such as liberalism or Marxism that is forward-looking or that looks impatiently at the present from the perspective of a future that it thinks it knows and, in thought, has already occupied [...] its view of the human world is not technological but poetic. Hume teaches that in a world of constant flux and dissolution,the metaphorical imagination forms identities which are housed in habits, customs and traditions [...] the tone, tenor and style of Hume's philosophy are therefore entirely different from empiricism, which is the tip of the ideological iceberg of progress [...]Hume's philosophy is founded on a philosophical act of self-inquiry like that of the Pyrrhonians, and therefore the structure of Hume's philosophy is quite different from what has come to be understood as empiricism. The central idea of empiricism is that there is an unproblematic foundation of knowledge given in experience and usually identified with sense experience, from which all knowledge is derived and against which all theoretical interpretations must be tested [...] the given in sense experience, being uninterpreted, or nearly so, is the only standard against which interpretations can be brought to account [...] [on the other hand] a skeptical philosophy in the Pyrrhonian tradition that finds philosophy itself to be suspect and, by inquiring into its nature, subverts all the recieved foundations of knowledge is not and cannot be a philosophy aimed at constructing an 'epistemology', empiricist or otherwise" -Hume's Pathology of Philosophy, Donald W. Livingston.

"Myths are stories about the nature of reality and our quest for wholeness, and they have been a pervasive feature of human culture for millennia. Even now, in an age dominated by technology, scientism, and global capitalism, myth has not released its hold on the human imagination. For many observers, scientific rationality long ago replaced myth and religion as the arbiter of truth, but this progressivist picture is itself a product of the mythical imagination, albeit a deformed one. Making sense of myth past and present depends on how one approaches this challenge: reality always outruns our cognitive grasp and all our representations, which are inevitably partial and inadequate. We can limit our perspective to domains over which scientific rationality exercises its limited authority. Or, in the face of life’s intractable puzzles and mysteries, we can enlist critical rationality to explore the myths and symbols which our deepest longings always call forth." Introduction to Eric Voegelin's Philosophy of Myth, John Bussanich

"Look at a rainbow. While it lasts, it is, or appears to be, a great arc of many colours occupying a position out there in space. It touches the horizon between that chimney and that tree; a line drawn from the sun behind you and passing through your head would pierce the centre of the circle of which it is part. And now, before it fades, recollect all you have ever been told about the rainbow and its causes, and ask yourself the question is it really there? You know, from memory, that if there were a hillside three or four miles nearer than the present horizon, the rainbow would come to earth in front of and not behind it; that, if you walked to the place where the rainbow ends, or seems to end, it would certainly not be 'there'. In a word, reflection will assure you that the rainbow is the outcome of the sun, the raindrops and your own vision. When I ask of an intangible appearance or representation, Is it really there? I usually mean, Is it there independently of my vision? Would it still be there, for instance, if I shut my eyes - if I moved towards or away from it. If this is what you also mean by "really there", you will be tempted to add that the raindrops and the sun are really there, but the rainbow is not. Does it follow that, as soon as anybody sees a rainbow there 'is' one, or, in other words, that there is no difference between an hallucination or a madman's dream of a rainbow (perhaps on a clear day) and an actual rainbow? Certainly not. You were not the only one to see that rainbow. You had a friend with you [...]in short, as far as being really there or not is concerned, the practical difference between a dream or hallucination of a rainbow and an actual rainbow is that, although each is a representation or appearance (that is, something which I perceive to be there), the second is a shared or collective representation" Saving the Appearances: A Study in Idolatry, Owen Barfield

The important points:
-Epistemology (or the study of knowledge) comes a posteriori to possession of knowledge and truth. First we have knowledge, and then we systematise HOW it is that we have it and what it means to have it - thus global skepticism is incoherent, because we can never doubt, without first knowing and hence believing. "Every mental act is composed of doubt and belief, but it is belief that is positive, it is belief that sustains thought and holds the world together" (S. Kierkegaard). "Truth is the criterion of itself and of the false" (B. Spinoza). In other words, every act of doubt entails an act of belief, whereas not every act of belief entails an act of doubt. "Dubito, ergo scio"
-For the same reason, philosophical systems (like religion!) are like geographical maps - they give a guide to the terrain for those who understand the symbols - but how does one learn what the symbols mean AND how to use them? A time comes when a whole generation has forgotten the symbols, and thus only anamnesis can bring back knowledge - it must be re-member-ed, constructed again, in a way that it can be understood and shared again. Systems die and are forgotten, but the truth they hold is immortal.
-Philosophical systems become useless once it is forgotten how they were arrived at - the experiences that led to their construction. "Even though one were capable of converting the whole content of faith into the form of a concept, it does not follow that one has adequately conceived of faith and understands how one got Into it, or how it got into one" (S. Kierkegaard contra Hegel et al.)
-Systems also prevent one from a direct encounter with reality; the map may so seduce the traveller that he will rather analyse the map instead of travel the route or worse, he may mistake the map for the terrain - in which case the System becomes the truth, instead of just another myth useful only-in-so-far as it helps one relate with the Truth. This breeds arrogance and forgetfulness of the way the community is the sustaining cause of the self, which is merely its effect. A healthy dose of Pyrrhonian skepticism, like Hume's, becomes a useful antidote to this, which must be followed by a re-enchantment, like Hamann's (he wasn't called the greatest genius of the time by the likes of Kant for nothing!).
-Modernity - if by that we understand progressivism, with all its associated changes - global capitalism, moral decadence, scientism, deculturalisation, atheism, irreligion, nihilism, absurdism, hatred of authority, alienation, isolation, love of money, love of technology, communal divisions, extreme socially left-wing identity politics, hypersexualisation, political correctness - is the system which has decieved itself that it is the Truth, and has mobilised all the means available to impose itself over the whole Earth, especially in the Western civilisations.
-Modernity has three pillars (1) reduction in the authority and power of individual politicians, and a general ridicule of the politician as a class; (2) reduction in the authority and power of the Church, and a general ridicule and hatred of religion; and (3) hypersexualisation, and enthralling sex as the new driving force and essential nature of man, which is the driving engine behind the deconstruction of morality. Somehow these are also the three topics it is not polite to discuss at a dinner table - one wonders why.
-As no system of philosophy can be equivalent to reality, a philosopher is one who remains critically aware of the limitations of all systems, and invites one to step further than any system can go, into an authentic experience. Custom, tradition, and religion remain the vehicles which can house truth and pass it on most authentically through ritual and communal behaviour from one generation to another. Ultimately, a real philosopher must also be a philomuthos - a lover of myth.
-As epistemology comes after knowledge, it can play no role in the acquisition of knowledge (premises), only in their systematisation.
-As Nature never lies, no philosophical system, myth, etc. is completely untrue - everything is true to a certain degree. The difference is made only in the completeness of the philosophy in question. Acquisition of new premises, or correction of false premises is achieved through experience - and this is encouraged through art and aesthetics, which enable one to gain new insights into life, by removing the blockages that happen to the will (not the intellect). As such, the most effective method of transmission is sharing of experience, and appeals to one's aesthetic side.
-Only experience, which discards as little as possible, followed by analysis such as the one performed by Barfield in the paragraph quoted, can enable one to come to a true understanding of the world. It will be a poetic understanding, and NOT a rationalistic one though, as all our representations always fall short of the mystery of the world

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I could add more, but this should be enough for now.