Has there every been anything which refutes Descartes' theory that all we can be sure of is that we are thinking things? Is there any proof that we can be sure that other people exist?

Is it possible that the Universe and how we perceive it are just fractions of what is really out there? How would we know that the universe is not some completely different place that we could not even begin to undestand or perceive? For example ants live their lives without ever knowing of our existence so how would we know that there is not a lot going on in this world that we can not sense?

If no one ever loves me during my lifetime - if I don't ever have a relationship - will I have not lived properly? Is love that important to life, or is it something you can choose to engage in if you like? Thank you.

Is the exploration of space worthwhile? What possible application does it have? The money spent on space exploration could have spent elsewhere on more 'worthwhile' causes like cancer research or the third world. When you think about this, the exploration of space seems like a waste of time and money.

Why do I ask questions that I already know MY answer to? Why would I change my mind if I am already sure that, for example, 'knowledge comes from experience' or that, 'there is no life after this one'? Are there any instances in which any of the philosophers on this site have radically changed their minds or caused others to change theirs?

Are there any websites that accurately rank (as far as that is possible) philosophy departments in non-English speaking countries with strong philosophy programs?

I was reading up on the study of whether biologists who accept the evolutionary theory believe in God(s) and other theologistic happenings. Many of them say that they find no conflict between the two whatsoever. How is this possible? Isn't the theory of evolution itself based on random, natural selection?

Why should I be concerned about torture? As a middle class, white atheist living in the UK, neither I nor anyone I know is likely to suffer from it. I consider my aversion to it to be mere sentimentality. Bill Foster

Is it possible to determine whether the laws of Physics as they are currently perceived will last indefinitely? Is there anything to prevent the nature of the universe changing so much tomorrow that reality as we know it breaks down?

How useful is Kantian ethics when discussing an issue like abortion? Is it easily applicable in real life situations and does it leave any room for meaningful discussion on the issue?