Annotation of achieved result: The objective of the research was to decide whether causation is an independent feature of external reality, or if it is a mere aspect of our knowledge. The later has been dismissed on the grounds that objects outside causal relations are, in principle, unknowable: dismissal of causation leads to agnosticism. However, the research proved that such realistic picture of causation faces difficulties as well. Mainly, a correct explanation of causation must lead to its reduction to some non-causal entities (in order to avoid vicious circle), but this contradicts the realistic position. This dilemma can be resolved by a non-reductive analysis (e. g. dispositional approach), which is still controversial topic. The research also proved the existence of non-causal knowledge and this disqualifies realistic position to causation as an adequate approach to epistemology. This is a serious consequence leading to revisions in scientific realism, but this topic is not properly discussed in the literature.