A trick to using malapropism is to ensure that the two words (the original and the substitute) sound similar enough for the reader to catch onto the intended switch and find humor in the result.
Positivism is a philosophical theory stating that positive knowledge is based on natural phenomena and their properties and relations. Thus, information derived from sensory experience, interpreted through reason and logic, forms the exclusive source of all authoritative knowledge.
Positivism is the belief that human knowledge is produced by the scientific interpretation of observational data. The approach has been an ongoing theme in the history of western thought from the Ancient Greeks to the present day. The term was used in the early 19th century by the philosopher and founding sociologist, Auguste Comte.