There are a few equations in theoretical physics, which in a slightly different modification cover dynamic problems of most physical systems. Moreover, in a mystical way, the same types of equations appear in completely "non-physical" areas like finance (Black-Scholes equation), political science (voting theory), ecology (population dynamics), etc. In this paper we show that fuzzy logic mathematical apparatus applied to common causal principal with some natural restrictions on a system state space, allows us to resolve this puzzle.