The article analyzes Bertrand Russell’s distinction between knowledge by acquaintance and knowledge by description contained in his writings from 1910 to 1912. I point to some problems that arise from Russell’s concept of direct knowledge if they are observed in the light of modern psychological and neuroscientific research. In some cases knowledge by acquaintance may be mediated by certain unconscious operations and by mental representations of conceptual nature. I point out however that some of the examples given in The Problems of Philosophy can be characterized by a different degree of indirectness. Consequently, I propose to view Russell’s distinction as a typology. Because Russell narrows knowledge by description to specific descriptions, Russell’s division is not exhaustive and therefore is not a logical one. The article also shows that there are reasons for both narrowing his category of direct knowledge (e.g. by excluding universals) and for expanding it (e.g. by unconscious experiences).

The article addresses the problem of properties and epistemic functions of Russellian ‘knowledge by acquaintance’ interpreted here as a variant of intuition. The epistemic functions of intuition can be performed in two ways: first, as propositional knowledge of direct and immediate kind (a foundational function), and secondly, as a non-‑propositional form of consciousness that provides a justifying basis for intuitive truths. The distinction between these two functions of intuition presupposes a differentiation – not explicitly articulated by Bertrand Russell – between acquaintance and knowledge by acquaintance. Acquaintance as a form of non‑propositional consciousness is not epistemically autonomous, which is to say that it is not a judgment and cannot be qualified as either true or false, so a separate epistemic problem arises here, one of the shift from acquaintance to knowledge by acquaintance. The author points out that the shift from acquaintance to knowledge by acquaintance is difficult to accomplish, and she offers the opinion that the epistemic function of acquaintance or, more generally, of various similar kinds of consciousness, should not be interpreted in terms of justification. They should be understood not as a justifying element or a justifying reason for propositions that underlie other propositions, but as a factor that is an indispensable genetic and simultaneously structural element of propositional content in the sense assumed in transcendental philosophy.

The distinction introduced by Bertrand Russell between knowledge by acquaintance and knowledge by description is the starting point for analyses related to the concept of acquaintance. I propose to assume that the following three concepts used by Russell are equivalent: knowledge of things, knowledge by acquaintance, and acquaintance. Then I present linguistic analyses concerning the construction of ‘know‑NP’ and ‘znać‑NP’, which lead to (i) division into a direct and indirect acquaintance and (ii) separation of knowledge from acquaintance, recognizing them as two different cognitive relations. Then, through the prism of knowledge, I describe the concept of acquaintance, pointing to the common properties of these concepts (aptness, non‑voluntariness, dispositiona-lity, contextual dependency), and postulate similar normative functions. This paper can be treated as an introduction to the concept of acquaintance and an elucidation of its role in epistemology.

Charles Travis argues that perception has no representational content and consists only in the relation of direct presentation (acquaintance) of mind‑independent particulars. He bases his argument on an interpretation of Gottlob Frege’s writings. I argue against Travis that, according to Frege, not only perceptual beliefs but also perception as a presentation of particulars has representational content. The paper identifies three problems for the claim that perceptual acquaintance involves representation.

In a few short paragraphs of The Problems of Philosophy Bertrand Russell presents his theory of introspective knowledge based on the concept of knowledge by acquaintance. In this article, I critically analyze these comments by Russell and their proposed application by contemporary authors, including Brie Gertler (2001; 2011) and Laurence BonJour (2003). I show how these theories differ from the competing ‘inner‑sense theories’ and try to show that they are inconsistent with Gareth Evans’s ‘transparency’ observation. Then I compare acquaintance theories with Alex Byrne’s (2005; 2012) ‘transparency’ theory and show that Byrne’s theory offers a simpler account of mechanisms governing introspection and attribution of mental states to other agents than the observer.

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