Having grown tired of reading secondary material in my study of philosophy, I have decided to read primary texts in a chronological, rather than thematic, order. I have started with Plato and have read most of the works I can find online or at my library. Before I move on to Aristotle, I would like your advice. Do you think a chronological approach is a good idea for someone untrained in philosophy? Do you think I should read every work by a given philosopher, or are there 'key' works that serve as their primary contribution to the field? If the latter, are there any lists that you are aware of that state what those key works are?

I agree with Allen Stairs that reading topically is important, but I think it is equally important to remember that philosophy is a conversation that has been ongoing for something like 4500 years. To join in on the conversation, it can be very useful to see it historically , to see how it began and how it evolved, and thereby to gain an understanding of why it is where it is today. One can combine these approaches: Read chronologically within a topic. Or read contemporary philosophy alongside its history. To compare philosophy with physics, as Stairs does, misleadingly suggests that the history is irrelevant. (That's not to say that philosophy doesn't "make progress"; on that topic, see my essay: Rapaport, William J. (1982), "Unsolvable Problems and Philosophical Progress" , American Philosophical Quarterly 19: 289-298.)

Suppose that a neuroscientist is studying love, and she discovers that romantic infatuation is caused by high serotonin levels, while attachment is caused by oxytocin. Has she actually learned anything about love? More generally, what is the significance of discovering neural or hormonal correlates to particular human emotions or behavior?

Depends, of course, on what you mean by "love". Some philosophers and cognitive scientists distinguish between the (neuro)physiology of emotions like love and the phenomenal experience of love; others say that "they" are really the same, perhaps merely experienced from different points of view. If your neuroscientist is studying the phenomenal experience, then she has learned of a neurological correlate of at least one or two aspects of that experience. It's unlikely that she's learned how that neurological correlate gives rise to, or causes, the phenomenal experience, though some philosophers and cognitive scientists (such as the Churchlands) believe that eventually we'll cease talking in such terms (just as we no longer speak of diseases being caused by evil spirits). There is a famous (or infamous) thought experiment that is relevant to your question, but that reverses the roles a bit. You seem to have in mind someone who already knows about the phenomenal experience (in this case, of love)...

How do philosophers (or academics in general) justify their choice of profession? How is it defensible to be studying esoteric ideas with relatively few (if any) implications for the greater good, rather than devoting one's life to solving the much more practical problems that burden so much of the world's population? I realize that some philosophical ideas have had important worldwide impacts and have directly improved people's lives, but I doubt that almost any philosophers working today would say that that's what they expect to come out of their analyzing a particular view of Wittgenstein's or whatever. (I think this question ought to be asked of most professions, but it seems that philosophers would be thinking about this sort of thing much more so than would, say, investment bankers.)

How does anyone (not just philosophers or other academics) justify a choice of profession? One does what one is good at and what one likes to do. Academics in particular (philosophers included) need not apologize for their choice; we are, after all, teachers (in addition to being [perhaps] ivory-towerish scholars or researchers), and teachers surely serve the greater good. We philosophers, in particular, encourage critical (and skeptical) thinking, which--I suggest--is a Good Thing even if what we critique might be whether or not material objects are mereological sums of simples (or something equally esoteric). Some of us do try to help solve practical problems (and Karl Marx once observed that philosophers have only tried to understand the world but that the point is to change it--I would imagine those are fighting words to some, inspiring to others!). Yes, my analysis of Wittgenstein or, more obscurely, Meinong might not directly improve people's lives, but then again how would we prove...

How does one _prove_ that an informal fallacy is a fallacy (instead of just waving a Latin name?)

Peter's quite right, of course, but I think there's a bit more we can say. What makes a good pattern of reasoning good ( logically good, that is) is whether it preserves truth, that is, whether it only leads from true premises to true conclusions and never from true premises to false conclusions. (If it starts with false premises, that's another matter altogether.) And the best way to tell whether an argument pattern will be truth-preserving is to do a truth-table analysis of it: Assume (that is, make believe) that the premises are true, then figure out what the truth values of the atomic propositions are, and, finally, figure out what the truth value of the conclusion is. If, whenever you assume that the premises are true, it turns out that the conclusion has to be true, then you know the argument is a logically good one; otherwise, it is a "fallacy", i.e., a logically bad argument. See any introductory logic text for the details (I understand that Peter has a very nice one :-) There are a...

If I wanted to construct my own philosophy, how would I go about it? What tools would I need? How should I structure the process? What steps would I follow? Think of an ordinary guy - not someone seeking a PhD. Thanks, Mike

I'm not sure what you have in mind by "my own philosophy". Do you mean something like "your own philosophy of life"? Or do you mean something like "your own philosophy of (say) mind (or philosophy of language, etc.)". In the first case, I don't think very many professional philosophers can help you, because that's not the kind of thing that most of us do. But you might start by thinking about the things that are important to you, the things that you like, the things that you don't like, and then think about why they are important, and why you like (or don't like) them. And then try to similarly justify or explain those reasons, until you reach some basic principles that you can then take to be "your philosophy". In the second case, the best thing to do is to find some philosophical topic that you are interested in, read what historically important and current philosophers have to say about it, and then join in on the conversation.

Is anyone doing any serious work in Metaphysics these days? Anything accessible to someone with some philosophy background but not a professional? Thanks!

There is also a lot of metaphysically-relevant work being done by philosophers (and others) on ontologies. Ontology, as philosophers classically have understood that term, is the study of what there is, or of being. Ontologies, as that term is used by researchers in artificial intelligence, refers to what might be called the "syntax" of the world: A structured catalog of what there is, what properties things have, what relations they stand in to each other, etc. Link to the websites of the National Center for Ontological Research and of AI Topics/Ontologies , as well as the website of my philosophy colleague Barry Smith , for more information.

I'm thinking of buying a philosophy dictionary as I'm just starting to read philosophy books and finding there are a lot of terms I don't understand. There are a lot of philosophical dictionaries out there however and I was wondering which one you'd recommend?

Robert Audi's Cambridge Dictionary of Philosophy is another excellent one. But I dislike dictionaries, especially for philosophy, where proper explication of terms requires a bit more discussion than most brief dictionary entries allow for. So after reading a definition in either the Cambridge or the Oxford dictionaries, I strongly advise you to read more about whatever term you were looking up by linking to the excellent, on-line Stanford Encyclopedia of Philosophy on the right-hand side of the askphilosophers.org website (or google it, or click on the title in this response).

Hi, What are the best ways to get informed about the current research areas/topics in philosophy (especially in philosophy of mind and philosophy of cognitive science)? Thank you.

If by "current", you really mean "very latest", then one way is to keepup to date with the major journals in those topics. For a (partial)list, take a look at one of the webpages for my Intro to CognitiveScience course, " Sources of Information on Cognitive Science ". Depending on what kind ofaccess you have to a university library and its electronic journalofferings, you can also often subscribe to online table-of-contentsalerts for many journals. If by "current", you meant something more like "classic problemsthat are currently being discussed", then an anthology of recent orclassic readings is another way to go. Again, for a list, see the webpage cited above.

Why is it that the subject Philosophy is irrelevant for the secondarian level? Do we really have to wait until College just for us to enjoy this "mysterious gift"?

Iagree with Peter that the older you are, and the more you have read andstudied, the more likely it is that you will get something out of astudy of philosophy. But I think that philosophy can usefully bestudied before college (at what is called in the US the "secondary"level of education, i.e., high school) and that philosophicaldiscussions can usefully be had even earlier, at the primary, orelementary, school level. The American philosopher Gareth Matthews haswritten several wonderful books detailing his work withelementary-school kids on philosophy and has a website devoted to it: " Philosophy for Kids ". And Montclair State University has a program on both elementary and secondary education level philosophy: the Institute for the Advancement of Philosophy for Children . Inaddition, the American Philosophical Association publishes a Newsletteron Teaching Philosophy , which often treats of what is sometimes called"pre-collegephilosophy" (which term you can "google" for...

Are so-called "slippery slope" arguments effectively appeals to modus tollens?

I'm not sure that there's any single standard form for a slippery slopeargument, so let's look at just one, a "sorites" or "heap": If I havea heap of stones and remove just one of them, I still have a heap. Repeating that, I will always be left with a heap. But, obviously, atleast when I remove the last stone, I no longer have a heap. Therefore... Well, therefore, what? A heap of stones is equivalentto having no stones at all? Suppose so. That's "obviously" incorrect,so (a) the original premise or (b) some step in the argument must havebeen wrong. Suppose (a). Then a heap of stones with one stone removedis not a heap. This does indeed seem to be an application of modustollens, which is the inference rule that says: From "p implies q" and"not q", you may infer "not p". Here, p is our original premise, q isthe conclusion of the slippery slope. But (b) it could be that there'snothing wrong with either p or with q, but that what's wrong isrepeated application of stone-removal. In...