Evidence is reviewed suggesting that, in the general population, empathizing and systemizing show strong sex differences. The function of systemizing is to predict lawful events, including lawful change, or patterns in data. Also reviewed is the evidence that individuals on the autistic spectrum have degrees of empathizing difficulties alongside hypersystemizing. The hypersystemizing theory of autism spectrum conditions (ASC) proposes that people with ASC have an unusually strong drive to systemize. This can explain their preference for systems that change in highly lawful or predictable ways; why they become disabled when faced with systems characterized by less lawful change; and their "need for sameness" or "resistance to change". If "truth" is defined as lawful patterns in data then, according to the hypersystemizing theory, people with ASC are strongly driven to discover the "truth".