Stephen Hawking, in his recent book entitled The Grand Design, states that philosophy is dead. Without going into the reasons behind his thinking, I'd like to know the response of current philosophers to Hawking's statement. He has laid down a gauntlet of sorts, a challenge to philosophers to make their work relevant to the recent advances and discoveries made by cosmologists, astrophysicists, and others on the cutting edge of scientific discovery and investigation. Are present-day philosophers up to Hawking's challenge?

Scientists who write obituaries for philosophy forget that science depends on philosophical assumptions. When some lab results or observations of the visible universe confirm or disconfirm a prediction in physics, Hawking and colleagues draw conclusions about the whole universe. But does any set of observations justify conclusions about unobserved cases? Is "elegance" an objective feature of a theory, and does it make a theory having it more likely to be true? And so on. Philosophers grapple with these questions; scientists just presume answers to them. Unless we ignore such questions, philosophizing is inescapable.

Struggling with Wittgenstein. "The World is all that is the case". Does this mean both positive facts ("Paris is the capitol of France") AND negative facts ("Lyon is not the capitol of France") I can say "It IS the case that Lyon is not the capitol of France". Or does Wittgenstein mean only the pos. facts, i.e what has been actualized? Thanks.

I don't know what Wittgenstein was up to, i.e., whether he'd include among the facts of the world the "negative" fact that Lyon isn't the capital of France. As the questioner says, it plainly "is the case" that Lyon isn't the capital of France, so the first line of the Tractatus suggests that this fact does help comprise the world. But that's just my conjecture. At least one questioner wanted to see more give-and-take on this site, so I thought I'd query Prof. George's answer. It seems to rely on the unstated premise that if we have to list facts in order to describe the world, then that implies (or gives us some reason to think) that the world is a collection of facts. But in order to describe the Eiffel Tower, we can't just list all of its parts; we'd have to list facts about the Eiffel Tower. I don't think that gives us any reason to conclude that the Eiffel Tower is a collection of facts rather than a concrete, physical object.

I know some philosophers think numbers exist, and some others think the opposite. Do some of you think that this question is or may be "undecidable"? I mean, perhaps both the idea that numbers exist and the idea that numbers don't exist are consistent with all other things that we believe (do not contradict any one of them). Do you think this might be right?

Not really my area, but until someone else responds... I can see why you'd be tempted to think so. If numbers -- standardly understood as abstract objects -- exist, they're causally inert, and so they can't affect the world in any way. But I'm not sure that implies that their existence is just as compatible as their non-existence is with everything else we believe. It's highly plausible that numbers are essentially noncontingent: they exist necessarily if they exist at all. The concept of number doesn't seem to be a concept that could be instantiated only contingently. So, given common modal assumptions, it's either necessarily true that numbers exist or else necessarily false that numbers exist. Whichever one of those it is, then, the other one is impossible and hence inconsistent with everything we believe. Now, we might never be able to discover that inconsistency, and so the question whether numbers exist might be undecidable in that sense. But I'd be surprised if it were...

For me the answer to the question of whether abortion is right or wrong depends on the ontological status of the fetus. Is a fetus the kind of being that has a right to live or is it not? I don't know. How on earth can I know that? If I knew then I wouldn't be an agnostic on this issue. Most people, if I am not mistaken, take it for granted that a new born baby has the kind of being that gives it the right to live. So what reason is there to think that a young baby has the kind of being that gives it the right to live? What about an older baby or an adult...if we can stretch this question to its limits.

Your questions raise a host of difficult issues. What gives anything a right to life? In other words, what in general (if anything) about an individual makes it morally wrong for others to end its life? I've never seen a satisfying answer to that basic question. Does an individual's right to life inhere in the individual, or does it instead depend on the individual's relations to others? Prof. Manter referred to "all the relational complexities that being persons entails." If by "persons" she meant "beings with a right to life" and if by "entails" she meant some kind of logical implication (and it's possible she meant neither), then she's implying that a right to life doesn't inhere in the individual. I'm not sure I'd accept that consequence. Suppose you become a hermit and totally disconnect because you're tired of other people. If you had a right to life before you chose total isolation, then I'd say you still have it, and it would be at least presumptively wrong for any of us to...

Who´s happiness is most important? My own or my family´s wich I have a responsible for as a mother and a wife? I´m used to, and it´s a part of my personality to always make sure that everybody around me is happy and content.But I suddenly realized that I forgotten all about me and what I want and need to be happy. I´m now facing the fact that in order to be happy and content, I need a divorce. Our marrige with two teenagers, is OK, but nothing more- we are like best friends. I suppose that my action will come as a complete surprise to everybody around us. And it will cause a lot of anger, tears and questions. And the only answer I have is- I have to do this for me. Do I really have the ethic right to hurt everybody around me in order for me to be happy.

Your questions are important and obviously deeply-felt. I hesitate to offer answers to them because I don't think I'm particularly qualified as a philosopher to do that. But there are philosophers who hold themselves out as qualified; they're known as "philosophical practitioners," and you can find out more at this website . I don't know enough to say whether they're any good. But a couple of responses do occur to me. You say that you're "responsible" for your family's happiness. If by that you mean "solely responsible" or "more responsible than any other member of the family," then I'd respectfully disagree. I don't see why one parent in the family has more responsibility for the collective happiness of the family than the other does. You also ask if it would be ethically OK for you to divorce if it hurts others. Unless you have reason to think that your divorce would be more hurtful to others than most divorces are, then really you're asking whether divorce, period, is...

Are definitions falsifiable? It seems that if I find something of category X that does not fit category X's definition, then it isn't actually of category X, and thus doesn't prove anything. But on the other hand, if that is the case, it seems no definition cannot be falsified or otherwise demonstrated to be inadequate (unless it is inherently contradictory or so).

Let's focus on the phrase "something of category X that does not fit category X's definition." One on interpretation, we can't possibly find something of that description: if it doesn't fit category X's definition, then it's not something of category X, as you say. But that interpretation assumes that I've already got a correct definition of category X, a definition that's neither too broad nor too narrow. What if my definition of 'chair' is 'item of furniture with four legs' and you show me a bean-bag chair or an IKEA Poang chair? Haven't you shown me an item of category X that doesn't fit my definition of category X? Haven't you falsified my definition of 'chair', at least as a definition of the word in ordinary use, by showing that it's too narrow? (It's also too broad, as I realize when you show me a four-legged table.)

Is similarity a fact of things in the world, or is it an observation made by sentient beings? Take two cats, for example. Is it an objective fact of the world that the two cats are similar (shape, size, biology, etc.)? Or are there, ontologically speaking, just two phenomena (or two portions of the phenomenal world) that we, as conscious beings, perceive as similar and categorize as cats?

I think it depends on what's meant by 'similarity'. If similarity is just the sharing of properties -- having in common this or that attribute -- then it would seem that any two things are similar. Even Barack Obama and the Battle of Hastings have lots of properties in common: being known to historians, being the subject of books and articles, being distinct from the number 3, being referred to by me in this sentence, and so on. (You might reply that similarity is only the sharing of intrinsic properties, but it isn't always easy to draw a line between intrinsic and extrinsic properties.) So from the perspective of the world, any two things are similar -- and maybe equally similar, since any two things share infinitely many properties. But almost all of those properties will be uninteresting to us, and that's where we come in. From among those infinitely many properties, we conscious beings focus on just a handful in accordance with our interests. If we restrict ourselves to...

It has long seemed to me that philosophers do not seem concerned with illusion, i.e., the appearance of reasoning that SEEMS valid but is at least questionable if not illusory. The Greek philosophers that I read in school seemed particularly questionable. My impression was that much of their argumentation was illusory, i.e., based on claims that are unidentified assumptions. An example of illusion is the argument that since everything has a cause, there must be a FIRST cause. This SOUNDS sound but of course is not. Causality is not simple and is not a matter of logic. Causality has to do with nature and we know very little about nature. For all we know the universe has been going on forever, i.e., had no beginning. Moreover, if EVERYTHING has a cause, then there cannot be a FIRST cause which is exempt from having a cause. Are there philosophers who are concerned with this problem of illusory or unfounded philosophical reasoning? I would love to read their ideas. Please note that I'm not calling...

You wrote, "It has long seemed to me that philosophers do not seem concerned with...reasoning that SEEMS valid but is at least questionable if not illusory." I must say I find that surprising, since philosophers devote a great deal of their time (and some of them virtually all of their time) to exposing hidden assumptions, faulty inferences, equivocations, etc., in the arguments of other philosophers. Indeed, much of the progress in philosophy comes from exactly this activity. The First-Cause Argument that you mentioned is a great example. Its many versions have been subjected to detailed and powerful philosophical criticism for centuries. You'll find a helpful summary of that criticism here . Among the important objections is one that you raised: Who says the universe had a beginning? There are quasi-scientific arguments that it did in fact have a beginning (based on Big Bang cosmology) and philosophical arguments that it must have had a beginning (based on the alleged impossibility of...

I was reading some questions on this site regarding vagueness and the Sorites conundrum and I'm not sure I understand the fascination with figuring out what does or doesn't qualify as a heap. Isn't the word heap useful precisely BECAUSE it doesn't have a strict quantitative requirement? We choose to use the word "heap" and not a different word (like grams, or tons, or twenty-seven, etc.) because it offers us flexibility. I'm not sure exactly why this "puzzle" has received so much attention. The fact that there hasn't been an accepted solution makes perfect sense to me because there is nothing to solve. It seems like trying to apply precision to a word intentionally designed to be imprecise. It seems to me that if we figure out the exact point at which something becomes a heap then we will no longer be able to use the word as freely. Am I misunderstanding the problem? Thanks in advance!

I think you understand at least one aspect of the problem quite well. As you say, words like 'heap' are useful only if they're vague. Indeed, their vagueness seems built into their meanings: they're essentially vague; they wouldn't be the words they are if they weren't vague. The problem is that their vagueness seems to imply the contradiction that is the sorites paradox (see the two SEP entries that I cited here ). And it's not just 'heap', a word we might not care too deeply about. Practically every concrete noun and ordinary adjective we use ('car', 'fetus', 'child', 'person', 'tall', 'rich', 'unjust', 'toxic', 'honest', 'safe', and on and on) is essentially vague and hence apparently implies a contradiction. Yet we can't help thinking that plenty of things do answer to those nouns and adjectives. Surely there are rich people and toxic chemicals, but the sorites paradox seems to show that there can't be. It's as ubiquitous as it is hard to solve.

On 2/2, I asked: What I remember from my philosophy courses is the spirited debate, lively dialogue. For me this site is too question-and-answer, like the Stanford Online Encyclopedia that is often pointed to in the responses. Is there a place on the web where I can find a more dialogue-based form of philosophy? In reply, I received 2 replies bemoaning the quality of thinking found in philosophy chat rooms. I don't believe my question implied that I wanted to chat with morons in a "philosophy chat room", but let me clarify: I graduated with a BA in philosophy from what was then ranked as the #1 liberal arts college in the US, so I'd say I can tell the difference between people who can't reason their way out of paper bags, and philosophers. But the responders seem to imply that, at their level of philosophical accomplishment, there isn't much more to be said after one respondent has answered. In my view, this implies that the quality of the questions is poor, not provoking spirited dialogue from the...

Just for the record, neither Prof. Smith nor I bemoaned the quality of thinking in philosophy chat rooms, having made it clear that neither of us had ever visited any. But we both have serious doubts about the quality of philosophical conversation to be found there, if any exist. My doubts stem from seeing non-philosophers post and comment on philosophical topics, as I said. With your own training in philosophy, you'd find those threads deeply disappointing too, I'm sure. Prof. George suggested you might find the philosophical give-and-take you're seeking on blogs run by philosophers, but naturally those focus on whatever topics the bloggers currently find interesting. If your interests happen to match theirs, and if they allow comments, you'll find something on which to comment. David Chalmers maintains a long list of philosophy blogs here . I myself like the way AskPhilosophers functions. You wrote, "[T]he responders seem to imply that, at their level of philosophical accomplishment,...

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