Contemporary philosophical realism is the belief that our reality, or some aspect of it, is ontologically independent of our conceptual schemes, linguistic practices, beliefs, etc. Realism may be spoken of with respect to other minds, the past, the future, universals, mathematical entities (such as natural numbers), moral categories, the material world, and thought. Realism can also be promoted in an unqualified sense, in which case it asserts the mind-independent existence of a visible world, as opposed to idealism, skepticism, and solipsism. Philosophers who profess realism state that truth consists in the mind's correspondence to reality.