  Kotarbiński developed a general doctrine, called reism. It has two aspects, ontological and semantic. Hence, we can speak about semantic reism and ontological reism, although this distinction was clarified by Kotarbiński later. In general, reism goes against the acceptance of the existence of general (abstract) objects, that is, facts, properties, states of affairs, relations, etc. The main ontological thesis of reism is as follows (it is subdivided into two subtheses): (R1) any object is a material, spatio-temporal, concrete thing; (R2) no object is a state of affairs, property of relation (according to Kotarbiński, these three categories exhaust the domain of alleged abstract objects). Now (R1), that is, the positive thesis of reism has a rich content. Firstly, it marks a formal feature of existing objects, namely their concrete character.