during this publication the writer keeps that fertility declines independently of its “background”. in most cases, fertility decline is believed to ensue due to alteration within the socioeconomic historical past corresponding to the decline of the child mortality cost, urbanization, the extent of literacy, and so forth. This perspective has been considered as similar to “demographic transition”. besides the fact that, the concept that of demographic transition is so superficial, naïve and unscientific that it may be utilized only to the ostensible demographic phenomena, to not the mechanisms of fertility decline. the writer regards this fashion of pondering, i.e., that the prevalence of fertility decline relies on socioeconomic heritage, because the “background dependence” of fertility decline. to the contrary, there's significant counterevidence to the historical past dependence of fertility decline. The argument is made that history dependence lacks optimistic proof and predictability and hence, is falsifiable. That decisive counterevidence is brought during this publication. the writer revives the diffusion speculation of fertility decline on the element of the variety of young ones in step with couple because the reaction–diffusion strategy in a mathematical equation. Fertility decline in Europe within the eighteenth and 19th centuries happened as a reaction–diffusion technique self reliant of socioeconomic heritage. In Japan besides, fertility (the variety of kids according to couple) declined independently of historical past. This e-book offers considerable evidences persuasively demonstrating this independence of fertility in Japan. The prevalence of marriage can be self reliant of socioeconomic background. Thus the writer formalizes the wedding functionality as an quintessential equation of marriage likelihood, therefore, it demonstrates a greater healthy with the saw information than does the other marriage functionality. prevalence of marriage is nearly exclusively depending on the density of marriages that ensue in a given subspace.