Not everyone thinks that knowledge has intrinsic value -- after all, many people purport to subscribe to the claim that ignorance is bliss. This was the position taken by Cypher in the movie The Matrix -- he thought he would have been better left in The Matrix, thinking that he was tasting a delicious steak, even though it was all just a fiction. Cypher's seems to be that knowledge lacks any intrinsic value. But we can perform some thought experiments to check our own intuitions on the matter. Suppose some aliens kidnapped you, took you to their planet, performed some experiments on you, and then returned you to your bed. But before they did any of this they gave you some powerful drugs to keep from you any knowledge of the whole experience. In thinking about such a case, many people think they are worse off for not knowing what happened to them. This lack of knowledge seems bad, over and above the harm of the experiments themselves. Or, if you've seen the movie The Truman Show , think...

Good question -- something that a lot of people worry about. Tolstoy famously fell into a deep depression about this very question. He ultimately decided that the only way to find meaning in life was through faith, and he embraced God. But many philosophers have disagreed that this is the only route to meaning, and they have argued that meaning in life in possible even if God does not exist. In part this depends on what we take "meaning" to be. You put it in terms of "purpose", but tht might not be the only way to think about it. Philosophers like Richard Taylor have argued that we can find meaning by seeking inner fulfillment -- living a fulfilled life is to live a meaningful life. Alternatively, other philosophers like Peter Singer have argued that we can find meaning in life by adopting objectively worthwhile projects, ethical projects. By doing good -- be it working to end world hunger, or curing diseases, or fighting injustice -- we can infuse our lives with meaning. And yet other...

In thinking about your question, it may help to think about cases where we intuitively think lives lack meaning. Many philosophers have used Sisyphus -- who was doomed to push a stone up a hill, only to have it roll back down again, for all of eternity -- as a paradigm case of a meaningless life. To varying extents, our own lives often seem Sisyphean. My suspicion is that's probably more the case for lawyers and tax accountants than for volunteers. In fact, I have to confess, there are days when grading student papers seems awfully like rolling a stone up the hill! But now let's ask: What makes Sisyphus's life meaningless? Some have attributed the meaningless of his life to the misery he must be in. So we might try to consider a slightly different case, one given to us by philosopher Richard Taylor. Taylor suggests that we imagine Sisyphus having been injected with a drug that provides him a passion for stone-rolling. He still spends eternity involved in stone-rolling, but now this...

Speaking of sick jokes: I just typed a long answer to your question and then hit the wrong key before submitting it and now poof, now it's in the ether. But alas let's try again. In Douglas Adams' The Hitchhiker's Guide to the Galaxy it takes Deep Thought 7 and 1/2 million years to compute the answer to the question of Life, the Universe, and Everything. On the day the answer is to be revealed, the people are understandably excited: "Never again will we wake up in the morning and think Who am I? What is my purpose in life? Does it really, cosmically speaking, matter if I don't get up and go to work ?" And then the answer comes: Forty-two. The people are, to put it mildly, disappointed. When pressed, Deep Thought tells them: "I think the problem, to be quite honest with you, is that you've never actually known what the question is." So what is the question of meaning that you're asking for? What are you looking for, that you're not able to find? Some philosophers,...