2009 reprint of 1925 edition. This is an important book of one idea, but that idea is a very important one for the social scientist. According to the author "many thought processes and thought constructs appear to be consciously false assumptions, which either contradict reality or are even contradictory in themselves, but which are intentionally thus formed in order to overcome difficulties of thought by this artificial deviation, and reach the goal of thought by roundabout ways and by paths. These artificial thought constructs are called 'Scientific Fictions' and distinguished as conscious creations by their 'as if' character." Vaihinger's work is an important early contribution to the human tendency towards self-deception.