Drawing upon latest studies in the history of parascience, this review article demonstrates crucial differences between its main branches at the turn of the 19th century. The author calls for a careful approach in using «presentist» historical methodology and highlights the motivations of both scientists and those labeled «stepchildren of science», who tried to find universal principles regulating the processes in the world of nature. The degree in which scientific ideas correlate with personal value biases may be used as a possible criterion for demarcating the boundary between scientific and parascientific discourses.