scepticism

Ancient philosophical view that absolute knowledge of things is ultimately unobtainable, hence the only proper attitude is to suspend judgement. Its origins lay in the teachings of the Greek philosopher Pyrrho, who maintained that peace of mind lay in renouncing all claims to knowledge.

It was taken up in a less extreme form by the Greek Academy in the 3rd and 2nd centuries BC. Academic sceptics claimed that although truth is finally unknowable, a balance of probabilities can be used for coming to decisions. The most radical form of scepticism is known as solipsism, which maintains that the self is the only thing that can be known to exist.