Let's say time machines exist. What would happen if you got into a time machine, went back in time, and stopped the invention of time machines? Larry 16, NJ

If time machines have been invented, then no-one can change that. Ifyou were to step into a time machine, travel back in time and try toprevent the invention time machines, you would fail.

My teacher said all violence ever does is create more violence, and that even if you use violence for good you're doing nothing long term. What do you think? Larry, 16, NJ

I think that that is a very good rule of thumb. Humans often react to violence by retaliating. Hence many of the absurd feuds and wars that go on. Of course, one can think up exceptions. But they are rare.

When philosophers pose theories of language, are they implicitly dealing with just human language, or are their theories meant to address all possible languages?

Philosophers of language explicitly deal both with issues concerning all possible languages and with issues concerning just human languages. They usually make clear which of the two they are discussing at the time.

In what way do the social sciences and natural sciences differ as science? Are the social sciences "less" scientific?

A great deal has been written on that, and opinions vary. I willjust give you mine. 'Science' and 'scientific' are not themselves terms of science. Somephilosophers have attempted to give the terms a clear meaning (KarlPopper, for example). I think they have failed. And I don't think thatthe ordinary language terms 'science' or 'scientific' are very clear oruseful. So I would suggest that your questions aren't good ones.Further, there are many branches of natural science and many branchesof the social sciences and there is probably little to be learnt fromcarving the whole lot into two groups and trying to compare andcontrast them. Better: look at each branch of study that interests youand see if the theoretical claims are properly justified.

Is it morally acceptable for the rich to use their wealth to hoard an *essential* resource (such as housing) in order to make a profit?

One's answer to that might well depend on one's general politicalorientation. There are those who think that property is theft (a sloganassociated with Karl Marx and Pierre-Joseph Proudhon). Such peoplewould tend to answer your question 'absolutely not!'. Others believethat people can and often do own things and do have a right to hoard,if they choose to: it would be a good and generous thing for thewealthy to share their resources. But they are not morally obliged to.Personally I think it is hard to justify the institution of ownership.John Locke famously attempted to do so. (I think this was related to his defence of British colonialism in America). Roughly speaking (if I remembercorrectly, which perhaps I don't - maybe someone will correct me if Iam wrong) his idea was: God gave the Earth to mankind in common. So ifthere is some as-yet-unowned good, you have a right to put it to use -mix your labour with it and thereby increase its value. Since you own your body, you thereby come toown the good....

What do we owe to people who don't yet exist? Intuitively, it seems to me that we shouldn't, say, cause widespread damage to earth because it will so valuable to our descendants. But can we really be said to be doing something wrong to someone who doesn't exist? And would it be wrong to do something that would cause them never to exist in the first place? It seems that if we can do moral harm to future people, but it isn't wrong to cause them to never exist, then it morally superior to never have children rather to bring children into the world in which you have done the *slightest* damage. (The children, of course, would disagree.) But if it is wrong to cause them to never exist-and, since they would drastically prefer to exist-then we have a tremendous burden to reproduce as much as possible. If it make any difference, I am interested in how these question relates to our burden to reduce catastrophic/existential risks to the human species (global warming, nuclear war, gray goo, etc.).

That's a lot of difficult questions! First: I think we can do wrongto people who don't yet exist. It seems unfair to be less respectful ofsomeone who will be born in, say, 2020 than someone who was born in,say, 1995. Second: it is not obvious that your second question makesmuch sense. You can't do wrong to a being who doesn't exist, never hasexisted and never will exist, simply because there are no such beings!A future being isn't yet around to be harmed, but will be later. But non-existent beings aren't there to be harmed. You go on toconsider a conditional: 'if ... it isn't wrong to cause them never toexist ...' where 'them' is supposed to refer to future people. But ifwe cause there to be no future people then 'them' doesn't refer andthere is no issue about harming them. Still one might wantto argue that we have a duty not to make the planet uninhabitablebecause we have a duty to our species. I am not sure how to justifythat, but the thought seems to have some intuitive appeal.

Hey, A question of art. What can philosophy say about the emergence of the new art forms of the late 20 century? Can a computer programmer in any way be an artist, can a video game be considered art, even when its primary focus is to entertain, can a whole web page be a work of art? Thanks by advance

Well, if by 'the new art forms' you mean such things as video games and web pages, then it looks like you have answered your own questions in the affirmative. To me that seems the right answer. A video game could be both art and entertainment, a web page could be both a work of art and a means of communication, just as a building designed by Gaudi could be a work of art and a house.

Hi! I think this is a philosophical question concerning language. I just read this in a newspaper: "They share neither an underlying raison d'être nor a modus operandi." And the question is: what is the language of this sentence?

I'd say: If it is a sentence of a public language, then it's English. It has English syntax. All of the expressions in it are English too, though two of them have been adopted from other languages.