The source of the problem of negativity is the pre-Socratics’ philosophy. In the history of early Greek thought to the problem of non-being addressed, for example, Heraclitus, Parmenides, Democritus, Gorgias. It can be assumed that the teachings of the pre-Socratics are the basis of the subject of non-being in the concepts of subsequent philosophers. Attention is focused on the interpretation of non-being in Plato’s philosophy. In the «Sophist», non-being is understood not as the opposite of being, but as the «other» of being. The theoretical basis of this understanding of negativity is the pre-Socratic’ teachings about non-being.