The formalized axiomlogy construct the new foundation for research of an existential conditions of the possible worlds.

In this article, this distinction is clarified by the method of possible worlds that the one is just semantical rule and the other is an expression of empirical facts.

Going through the ancient stage, the modern classical stage and the stage of the theory of possible worlds, where the theory of reference improves itself continuously and overcomes its shortcomings, it, at last, leads itself towards the life world, where it finds its perfect and satisfactory explanation.

Logical Analysis to Possible World Counterfactual Conditional Sentence;

Examination of the possible world in Europead s geometrical system based on pure deduction;

On the Use of Conception of "Possible World" in Decision;

In the resistance of modernity against tradition a distinction has been made between the Natural Reason of philosophical tradition and modern Mundane Reason.