It is a serious quarrel whether there is a standard formulation of traditional syllogisms. It has been essential to designate the consequential relationship between propositions in the syllogistic argument. This problem depends on the syntactical construction. Lewis put forward in opposition to this syntactical construction "theory of strict implication". Lewis' investigations have led a new interest in modal logic. Theory of strict implication was introduced by Lewis in opposition to formulation of syllogism, for this formulation was called by him material implication. And material implication can not represents a valid inference schema