Several philosophical problems are based on an analogy between a real situation and a probabilistic model. Such problems are based on urn analogies. The present dissertation aims to describe and implement a methodology oriented towards the resolution of philosophical problems based on an urn analogy. This methodology is based on the use of the n-universes. To this end, I describe first the n-universes in a detailed way. I also discuss the difficulties of the theory of n-universes related to the demultiplication of the criteria and to the relation one/many between the objects and a given criterion.On the one hand, I present an application of the framework of n-universes to the Doomsday argument and to the problems recently appeared in the literature in keeping with the Doomsday argument. My concern is also with showing how the application of the framework of n-universes to several problems and thought experiments related to the Doomsday argument helps clarifying the problem data and making disappear the associated ambiguity. I present then an analysis of the following problems related to the Doomsday argument: the two urn case, God's Coin Toss, the Sleeping Beauty Problem, the Presumptuous Philosopher, Lazy Adam, and the Shooting-Room Paradox. I present lastly a solution to the Doomsday argument, based on a third route, by contrast to two types of solutions classically described.On the other hand, I present an application of the framework of n-universes to Goodman's paradox. I replace first Goodman's statement in the framework of n-universes. I propose then a solution to the paradox, based on a distinction between two different modelizations of Goodman's statement in two structurally different n-universes.