By themselves, these elements are not yet complete thoughts. The science of denoted classifies complete products of thinking, and it turns out that all of them, only the judgment is capable of being true or false. That judgment is therefore the main object of logic. Judgments are divided into simple and complex in simple judgments entered by the Stoics considered Aristotle kinds of judgments on the quality, quantity and modality by improving their classification by using precise definitions. In complex judgments Stoics distinguished connecting, dividing and hypothetical. In all these forms explored the formal conditions of their truth. The most extensively developed part of the logic of the Stoics - the formal doctrine of the syllogism; in it, according to their opinion, it is the goal of all logic. All other parts of logic are only the basis for the doctrine of proof. Feature Hrisippovoy inference theory is that, according to this theory, are primary and do not need further breeding is not simple reasoning, and those in which the initial premise - a complex judgment: hypothetical, connecting or separating.