Yes. Lots.

That's the easy answer. The hard answer is explaining how we could possibly learn anything true from a series of false statements. One answer is that good works of fiction use false statements to describe deep truths about human nature, emotions, relationships, morality, and the meaning of life. They do so by creating a world of characters and events that does not actually exist but that shares enough common features with our world that we can learn from them. Most importantly, the fictions may share the deep (and general) truths about human nature, etc. with our world, and they may do so because the writer has a deep understanding of these truths.

Fiction also explores the boundaries of the possible and teaches us to think about these possibilities. Philosophy often works in this way. By considering what is possible but not actual we learn something about our world and ourselves. Science fiction and philosophical thought experiments sometimes differ only in that the science fiction tends to be better developed and better written.

You understand the subject correctly, I believe. The study of literature has not always been done in this way, and is not done the same way everywhere. Saying that, the study of the way literature achieves meaning and certain effects, and the relation of these to the social or intellectual climate of the time, is a dominant way of doing things. Thus, for the most part, the study of literature is the study of how literature 'works', and not the validity of any ideas it contains.

However, it's not entirely lacking in usefulness! The study of literature might unveil subtle rhetorical ploys used to make an implausible idea seem self-evident; also it might (like history) help us to understand where ideas come from, why they were believed; finally, it might help us to understand the significance ideas have in people's lives, in part by dramatising how the consequences of beliefs or actions play out. All of these things are philosophically valuable.

A fascinating set of questions. Let me start by distinguishing at least two: 1. the issue of 'entwined' lives and their relation to individual autonomy. 2. The implications of this for 'ownership' of autobiographies.

The first of these is only a problem if we start with the assumption that everything that happens (in the human world) must belong to one and only one agent. As the saying goes, 'it takes two to tango'. You wouldn't have been 'free' to write about a relationship if there hadn't been another person! You were, in a sense, co-authors and co-owners of the events of the relationship.

The second question is more difficult. In fact, I think the example of the joint blog is not really appropriate. A blog is in the public domain, and is thus not a 'secret'. Your blog has been taken down but then the real moral issue is about respecting the wishes of someone who has changed their mind, and not about my 'ownership' of my own life. A better example would be intimate secrets that were never made public, and where the question of making them public never previously arose. Only then does the problem of my freedom to do what I like with the events of my own life arise in a pure way. However, the answer to the first question suggests that there is no paradox in saying that the events of your life belong to you and to other people.

So, I think you are right to feel moral qualms. Events of the relationship (such as writing a diary) are co-owned, even if you did the writing, and thus you have a responsibility to your ex-partner. Of course, the purpose behind disclosure might matter (making public the diary as part of a legal proceedings of some gravity, for example, might be morally compelling). Certainly, I would ask permission.

To add to Kalynne's answer, once you have identified a work of philosophy "broadly speaking," a useful thing to do is to reflect on whether or not that specific work is likely to meet your specific objectives for engaging with philosophy -- that question can be much more useful, I think, than simply understanding whether a given work can rightly be categorized as a work of philosophy.

Reading and reflecting on Pirsig, working your way through an introductory text, browsing within the Stanford Encyclopedia of Philosophy, and reading a set of specialized journal articles on a narrow topic each involve engagement with philosophy under one or another conception of what philosophy is, and each offer different opportunities for learning and growth. As you read around, you will get a sense of which types of texts offer which kinds of opportunities, and you may also get a better sense of which opportunities matter the most to you.

There is no reason that a novel cannot be a work of philosophy; in fact, I would argue that many novels are exactly that. Philosophy broadly construed is "the love (study/seeking/etc.) of wisdom," which can certainly be pursued through fiction. A little more narrowly, a work in philosophy would employ a certain style of inquiry, methodical or systematic or logical. Even more narrowly, it would contain references to, or even excerpts from, the standard philosophical repertoire; Jostein Gaarder's Sophie's World comes to mind here. While I have never read Zen and the Art of Motorcycle Maintenance myself, from what I have heard about it, I would consider it a work in philosophy broadly speaking -- that is, it gives you the impetus to ask the kinds of questions traditionally associated with philosophy.

My answer to this is a firm "Yes". Novels, for example, "tell the

truth" better than any other written material, with the exception

things like diaries and letters, unless you think of the relevant

passages of diaries and letters as though they were mini-novels. But

diaries and letters are no better at telling the truth in the

appropriate sense than the skills of their authors. What sense is the

sense in which novels (or more generally imaginative writing) can "tell

the truth" better than any other "Areas of Knowledge", as you call

them? (I imagine that you might have the sciences in mind.) The sense

is one in which telling the truth has to do with getting the details of

a description absolutely right, and getting the overal balance and

colour and mood of what one is describing absolutely right. Here

psychology for example (which might be thought to give "tell the truth"

better than the novel) is no better than the sensibility (the

eighteenth and nineteenth century word) of the individual working

psychologist. And psychology as a whole can be worse, because its

collective or institutional scientific structure blots out the most

personal and individual aspects of its subjects' lives. 'What an

intelligent man knows is hard to know', as Goethe observed. But I agree

with Kalynne Pudner that there is a rich and rewarding philosophical

literature that exists exactly on this topic. My philosophical guides in

the area, who share the view I have sketched above, are Iris

Murdoch and Vladimir Nabokov.

I'm hard pressed to answer this question (and I suspect I'm not the only one, seeing as it's been so long unanswered) without knowing more precisely what you mean by "tell the truth." A work of literature can be said to have various meanings, some of them mutually exclusive, and few (if any) constraints on viable interpretations. So in that sense, it would tell the truth, because the range of what it "tells" is so very broad. But it would be the same with the visual arts, wouldn't it?

If "telling the truth" is understood to be some kind of correspondence with an external state of affairs, then it seems other areas of knowledge (mathematics, for instance) would "tell the truth" better.

Aesthetics isn't my area, and so far I'm only dabbling in Phil of Literature; I'm afraid I can't do better than this for an answer. But it is an intriguing start to a conversation. I hope you pursue it.

Poetry can certainly be used to express profound ideas and attitudes concerning (for want of a better expression) 'the human condition'. These ideas can affect the reader's soul in a powerful way, helped along by the captivating power of the medium itself. And examples of poetry that might be regarded as 'philosophical' in this sense are innumerable. Indeed, one might make a case for claiming that it's the norm rather than the exception, and that this is the primary aspiration of most of the greatest poetry in history, from Homer to Dante to Sylvia Plath.

But does this really count as philosophy? For some people, this is precisely what the best and most important kind of philosophy consists in. For others, however, and particularly within English-speaking academia, philosophy is more a matter of highly technical and abstract theories about the structure of reality, the nature of cognition, and things of that sort. And yet, as it turns out, those kinds of theories have been explored in verse form too. One might compare this with the way in which philosophers from Plato to Berkeley to David Lewis have opted to present their ideas and arguments in the form of witty dialogues. Either approach brings, among other potential advantages, that of simply engaging the reader more effectively than yet another dry prose treatise might.

For an example, consider Lucretius's De Rerum Natura, an epic poem in six books from the first century BC. Lucretius set out and argued for, among other things: an atomistic physics, a plurality of worlds and extraterrestrial life, a theory of natural selection, a materialist account of the mind, a vigorous critique of religion, an account of the origins of human society out of a state of nature, a study of meteorology, and, believe it or not, a discussion of sexual positions. And all in Latin verse. Admittedly, that was then and this is now. Professional philosophers and scientists tend not to express themselves in verse any more -- I can't think of any recent examples (though perhaps others might). But, even into the early modern period, they were still doing so. See, for instance, the book-length philosophical poems, Nosce Teipsum by Sir John Davies (1599) or Psychodia Platonica by Henry More (1642). Some of the scansion and rhyme might have been a bit dodgy, but these authors did nevertheless feel that verse was an appropriate medium for the expression of serious metaphysical and epistemological theories and arguments. There's certainly no incompatibility between the poetic medium and even the most technical kind of philosophy.

The project of "improving" "the" language is one that has captured the imaginations of many people over time, but it seems to me to be a foolish one to undertake. Let me explain, by explaining my use of scare quotes.

First: "the" language. There's no such thing. If you look at speakers of so-called "English," you'll find that they will differ in their vocabularies, in their grammars, and above all, in the emotional and aesthetic associations they attach to their words. What binds us together is merely the fact that we can to a significant degree understand each other's verbal behavior. But the engines of linguistic change are perpetual motion machines. Slang, idioms, metaphors, abbreviations, invented words -- they all pop in and out of existence, and they're all good. Amidst all this variety, talk of "the" English language is nothing more than abstract idealization -- useful for some scientific purposes, perhaps, but not to be thought of as literally true of human linguistic activity.

Second: "improve". You can't improve a product until you know what function it's supposed to perform. Your suggestion -- that we invent words whose inherent properties resemble the things they refer to -- is presumably intended to improve language's capacity for expressing thoughts. Well, maybe it would, maybe it wouldn't. There's some reason to think that communication goes most smoothly when the referential properties of the linguistic medium are purely conventional -- when nothing about the word itself causes us to linger in thought about the relation betweent the word and the object. But in any case, it looks like people who find need of more evocative connections simply contrive them. That's how "sunny side up" became standard restaurant talk for "fried egg that has not been turned over in the pan." On the other hand, the number of such originally fresh expressions that have become dead metaphors suggests that the pressure of the communicative function causes the erosion of the meaningful associations. I recently overheard a child asking a grownup what he meant by the expression "broken record." And how many people can explain anymore what it is literally to "upstage" someone?

But in any case, language has myriad functions, and improvement in one area need not bring improvement in some other. Furthermore, human beings appear to be extraordinarily resourceful in adapting language to their particular purposes. One of the things language does, for example, is although us to express our understanding of social nuance. Not only do we observe linguistic conventions that encode social relationships -- consider the use of "titles" like "Mr." "Ms." "Dr." -- but we all recognize different norms of verbal expression appropriate to different social circumstances. We use different language when playing with children than when arguing with our mates than when attending a funeral. Moreover, we all recognize that styles change -- new linguistic forms are always developing, and old ones are decaying. Artists who work with language do what artists always do -- they exploit the inherent properties of their medium to create things with aesthetic interest. People interact with other people who speak differently than they do, and pick up some of their expressions. Scientists discover new things, and have to name them. Teenagers need to speak in a way their parents cannot understand. Politicians must contrive new euphemisms to obscure new crimes. With all these means available to use for adapting language to our news, what requires improvement?

As Nicholas suggests, it partly depends upon what you mean by 'wisdom'. Many philosophers (and others) have been attracted to the idea that art provides a kind of experientially-based 'insight' that pure argumentation cannot supply. One possibility here is that there are properties or propositions that we (or at least, most ordinary people living fairly ordinary lives) can only become acquainted with through art. This might be because the art provides a kind of substitute experience for a reality most of us will never experience (e.g. slogging through the fog of war), or because the art provides an experience that simply does not occur in real life (e.g. the sublimity of a symphony). Another possibility is that art provides us with a perspective on, or a mode of presentation of, properties or propositions that we might already be independently acquainted with; but that this perspective or mode of presentation leads us to appreciate the familiar propositions in a more profound and intimate way. Thus, Crime and Punishment might lead us to appreciate the truth of the cliche that "crime doesn't pay." Finally -- what to me seems intuitively closest to the notion of wisdom -- some people think that engaging with art can train our cognitive and emotional faculties to respond to real life in a more mature, nuanced manner. Thus, Martha Nussbaum (cf. esp. Love's Knowledge) suggests that novels are uniquely equipped to help us appreciate and negotiate the complex, highly context-laden challenges of ethical action because they provide us with a rich, experiential engagement with complex and ethically challenging characters and situations, in a context where our perceptions are not clouded by self-interest as they typically are in actual life, and where the author actively helps us to see things in an ethically responsible way.