"Could 'sideways thinking' be another term for what Arthur Koestler calls ? Koestler coined this term to describe a phenomenon he calls the 'Act of Creation'. It's the spark that ignites original concepts, an event that takes place in semi-consciousness or absent-mindedness where the mind is free-associating. Koestler likens it to a sort of mental short-circuit that sparks a connection between two hitherto unconnected frames of reference."