The aim of the paper is to provide an answer to the following question: How to interpret the principle of acquaintance and what role does it play in Bertrand Russell’s epistemology? It seems that the principle itself should be so adjusted as to take into account two concepts: (1) an act of judgment as a multiple relation and (2) the division of reality into what is directly given (sense‑data) and physical objects. I show, contrary to Russell’s assurances, that the content and the role of the principle is not clear, and its acceptance leads to a paradox. Having discovered that consequence, Russell abandoned the dualistic division of reality and with the help of the method of logical constructions, sought a position that embraced phenomena