In their gonessology, the Stoics were not consistent realists because they have taught, like cynics, that only the private, the single, and that the general notions do not really correspond to the existing general, but only mental intelligence summaries of the concrete. In other words, stoic gnosiology is nominative. But on the other hand, they have assumed that real real knowledge is possible, because if real knowledge is not possible then it is impossible and truly correct behavior.
Because you can not want something without knowing what you want, and you can not act, act wisely and correctly, without knowing the purpose, and without being convinced that it is a meaningful and reasonable goal.Especially in logic in the narrow sense, the Stoics' teaching about the categories is interesting. Unlike Aristotle, who accepted ten categories, they accept Kant in the new age four categories: substance / upokeim, upokeimenon /, quality constant, quality random or condition and attitude. These categories are in a strictly internal connection, because each following presupposes the preceding as its concept, to which it is only a type of term, marked by its species mark.
COSMOLOGY AND ANTHROPOLOGY
The worldview of the Stoics is infiltrated by the three-fold trend. In contrast to the Platonic-Aristotelian dualism, they seek to explain the world through a beginning as monists. In contrast to the transcendental platonic ideas, they teach immanent reasonability and ideality. Thirdly, in their view, everything in the world is the work of reason, and the ultimate foundation of the world must be Absolute Reason. So everything in the world is explained teleologically.
At first glance, the Stoic system seems materialistic. For, according to them, only bodily is true, because only it can act and suffer suffering. Not only everything essential, including the human soul and the Deity, is in their opinion bodily, but all the qualities of the soul consist of air currents or breaths. Thus light, whiteness, warmth are bodies; the voice is a body. Even virtues and vices, wisdom and stupidity are bodies. For the soul, Chrysippus says, "Death is the separation of the soul from the body. But nothing can not be separated from the body, and vice versa - non-intrusive can not be in contact with the body. The soul combines with the body and separates itself from it, meaning it is a body. "Only in contradiction with themselves, the Stoics consider that space, time, place and thought are not bodies. In fact, Stoics do not accept the existence of empty space, because they think everything is filled with matter that is only of varying degrees of compaction. In this regard, the Stoics deny the impenetrability of matter.