Historians using computers to apply quantitative methods and historians using computers for other things have strained relationships. This is not the result of mutual bad will, but results from genuine differences between information as provided by contemporary phenomena and that derived from historical documents. Only after these differences are taken care of quantitative and other formal methods are methodologically safe. A tentative model for a possible solution of part of these problems by fuzzy logic is presented. More generally we discuss which developments are needed in the application of information technology to historical research to ease the strained relationship mentioned at the beginning.