Skepticism or scepticism (see spelling differences) is generally any questioning attitude towards knowledge, facts, or opinions/beliefs stated as facts, or doubt regarding claims that are taken for granted elsewhere.Philosophical skepticism is an overall approach that requires all information to be well supported by evidence. Classical philosophical skepticism derives from the 'Skeptikoi', a school who "asserted nothing". Adherents of Pyrrhonism (and more recently, partially synonymous with Fallibilism), for instance, suspend judgment in investigations. Skeptics may even doubt the reliability of their own senses. Religious skepticism, on the other hand, is "doubt concerning basic religious principles (such as immortality, providence, and revelation)". Scientific skepticism is about testing scientific beliefs for reliability, by subjecting them to systematic investigation using the scientific method, to create empirical evidence for them.