If scientific theories claim to provide ultimate truths about the nature of reality, then how can we explain new theories and revisions of existing theories? To take an extreme example - if we once believed that the world was flat, how can we justify our current belief in a spherical world? In this particular case, our current ideas can clearly be explained by the increases in technology and no one would seriously question the shape of our planet. However, in more complicated instances how can we be so sure that science offers anything more than a set of beliefs (i.e. in a similar way to religion or myths).

Later scientific theories often contradict the theories they replace. Does this mean that science is not in the truth business? There is a simple and much discussed argument for this conclusion. The argument is known as the 'pessimistic induction': all scientific theories more than say two hundred years old are now known to be false, so it is likely that all present and future theories will eventually be found to be false as well. So much for truth. There are a number of responses those of us who do think science is in the truth business can give. We can quibble with the premise of the pessimistic induction: surely not all theories more that two hundred years old are now known to be false. For example, we still believe the theory that the blood circulates around the body, and that theory is much more than two hundred years old. But even if the premise is an exaggeration, lots of our best old theories are contradicted by what we now believe. For example, if Einstein is right, then...

If there was to be a theory of everything, like all theories it should be able to predict certain events, would it predict human action and behavior? Then wouldn't this theory destroy our ideas on free will? -Rafael Gomez, 15

Rafael, this is an excellent question, and philosophers do not all answer it in the same way. My own view is that predictability in itself is not a special threat to free will. Suppose that I have free will. Now suppose that you know me so well that you can predict every move I will make. So long as you don't use that information to influence me, but just know it, I don't think that takes away my free will. You are not interfering. One of the things that makes this question difficult is that we have trouble seeing how free will is ever possible, prediction or not. The classic dilemma is this. Either everything has a cause or not. If everything does have a cause, then it looks like you have no free will, because the chain of causes leading to your actions began before you were born. And if not everything has a cause, if in particular some of your actions are uncaused, then that doesn't seem like free will either. It seems just like a random event. In short, either determinism is true or...

If one is upset that the places they visit are too populated, such as coffee shops, beaches, museums, etc., is that frustration a sign of hypocrisy? To put it another way, if I resent crowds and wish that people would leave, but I don't leave, am I being a hypocrite?

There is nothing hypocritical about wishing that one was, say, the only person on a beach. On the other hand, if you don't just wish that other people went away, but you think they have an obligation to leave, then you are probably entering the hypocrisy zone.

One of my teachers says that there is no such thing as "absolute truth". Could you tell me if she is correct in this statement?

Philosophers disagree about this, but I think there is such a thing as absolute truth. We need to distinguish the question of truth from the question of knowledge. It may well be there there is no such thing as 'absolutely certain knowledge', something we believe to be true and that we couldn't possibly be wrong about. But whether we can know an absolute truth for certain or not, there could be such a truth. We need to allow that there may be certain statements that are not absolutely true or absolutely false, because they do not have a crisp enough meaning. One way this might happen is if one of the words in the statement is vague. So, it may be that a statement like 'People with exactly 100 hairs on their head are bald' is neither absolutely true nor absolutely false. But it doesn't follow from this that there are no absolute truths, because it doesn't follow that every statement uses vague words. There may be some areas where absolute truth is not to be had. Some people would...

Hello experts, I have a question that burns my mind. Rorty is usually considered as one of the most significant philosophers of today. However, I simply cannot understand him. Firstly, he speaks against epistemology, yet he argues for "pragmatism" (which I presume is a theory of knowledge). Secondly, he argues against metaphysics, yet he argues for "eliminative materialism" (which I presume is a theory of metaphysics). What is happening here? Seems illogical to me.

Here is a cartoon version of Rorty's radical philosophy. The job of language and thought is not to represent an independent reality, but to give us tools that help us to thrive. Some thoughts and ways of talking are better than others, because more conducive to thriving than others, and Rorty is trying to convince us that pragmatism talk and eliminative materialist talk is better in that sense.

What is meant by the phrase "owing it to yourself"? How can you "owe" anything to yourself? What "loan" are you repaying when repaying a debt to yourself? Do we, as a matter of fact, ever "owe" anything to ourselves?

I agree that this is a funny expression. It's not as if I can borrow money from myself and then get in debt to myself. Maybe we just use this expression to say something like: 'This is something you can do, it is perhaps not something you would do as a matter of course, but doing it would be good for you'. If that is roughly the meaning (I doubt that this paraphrase is exactly right), then at least it is not suprising that we came up with a short expression for it! The expression also raises what is perhaps a deeper philosophical question, which is whether you can have an obligation to yourself. I'm inclined to say that you can have such an obligation, for example that you have an obligation to yourself not to take dangerous drugs, but the question is difficult and controversial.

What is the basic difference between philosophy and science?

This is a surprisingly difficult question to answer. There are a number of answers that seem to have something going for them, but also face various difficulties We might say that science is empirical, based on observation and experiment, whereas you can do philosophy with your eyes closed. But some parts of science are highly conceptual and far removed from the data, and on the other side a number of philosophers have denied that philosophy or any other form of inquiry could be entirely independent of empirical evidence. We might say that science concerns how things are while philosophy concerns how things ought to be. But although questions about how we ought to act and what we ought to believe are central to philosophy, there are also other, more descriptive aspects of philosophy, such as metaphysical questions about what sorts of things exist. We might say that science asks questions that we know in principle how to answer, whereas philosophy asks questions which, although they seem...

Is it possible for a human to ever do a selfless act? When someone does do a seemingly 'selfless' act, it is normally because of religious duties or an excuse to brag about it at a later stage, or even to get that good feeling you get when you know you have done a good deed (which is essentially selfish, considering that you get a mental reward, instead of a material one).

A powerful demon gave me a choice at lunch the other day: either my children will thrive and I will think they are miserable (which will make me feel miserable), or my children will really be miserable but I will think they are thriving (which will make me feel very happy). The moment I choose, I will have no memory of having made a choice or indeed of having ever had lunch with a demon. You know what? I'm going to choose happy children and miserable me. I'm no angel, but that is a selfless act.

I'm interested in such statements as "Life is strange", "The world is an amazing place", etc. How meaningful are they when we don't have other examples of "life" or "world" to compare them with? If they are not meaningful (and I don't know whether you will conclude that they are) why do people have a propensity for making such statements?

Even if in order to find something strange or amazing you need something familiar or mundane to compare it with, we could make sense of your statements in terms of the variety within a single life or a single world. It would be something like the sentiment that no matter how much you have experienced, you are in for more surprises. So even though some things become familiar and mundane, there will always be new things strange and amazing. And maybe we can even have strangeness without familiarity, the amazing without the mundane. Could there be a life where everything is strange and a world where everything is amazing? I don't at the moment see why not.

Seeing as you are Philosophers I thought you would be the ones to ask this question. Is there, or has there ever been, any truth to the existence of the Philosopher's Stone?

You have probably asked the wrong website, since the 'Philosopher' in 'the Philosopher's Stone' does not refer to a philosopher but to a scientist, or an alchemist. The term 'scientist' was only invented in the 19th century; Newton was a 'Natural Philosopher'. And in fact Newton himself was centrally concerned with the search for the Philosopher's Stone. For Newton put an enormous effort into alchemy, and the Philosopher's Stone is what the alchemists were looking for, a substance that would convert base metals into gold. There is alas no reason to believe this substance exists. Transmutation of elements does occur -- think of radioactivity -- but we've no way to convert lead into gold.