Philosophical problems are unlike scientific or mathematical problems in that problems in philosophy are often refined rather than solved There is widespread belief that no philosophical problem is truly "solvable" in the conventional sense. As Bertrand Russell, in his 1912 book "The Problems of Philosophy" says: "Philosophy is to be studied not for the sake of any definite answers to its questions, since no definite answers can, as a rule, be known to be true, but rather for the sake of the questions themselves." However, even this is not universally accepted amongst philosophers. So it is that Martin Cohen, in his 1999 iconoclastic account of philosophy, 101 Philosophy Problems, offers as the penultimate problem, the question of whether or not 'The problem with philosophy problems is that they don't have proper solutions'.
He goes on to argue that there is a fundamental divide in philosophy between those who think philosophy is about clarification and those who think it is about recognising complexity. It has also even been disputed, most notably by Wittgenstein, that genuine philosophical problems actually exist. The opposite has also been claimed, most notably by Karl Popper, who held that such problems do exist, that they are solvable, and that he had actually found definite solutions to some of them.