He cited Greek (γνωναι and ειδεναι), Latin (noscere and scire), German (kennen and wissen), and French (connaître and savoir) as examples.
On the contrary, when one is not directly and immediately acquainted with a fact, such as Julius Caesar's assassination, we speak of knowledge by description.
When one is not directly in contact with the fact, but knows it only indirectly by means of a description, one arguably is not entirely justified in holding a proposition true (such as e.g. "Caesar was killed by Brutus").
[clarification needed] Per Russell, acquaintance knowledge is an awareness that occurs below the level of specific identifications of things.
According to Russell, acquaintance does not involve reasoning that leads the individual to form an inference that the thing possessing the quality is any specific “so-and-so”.
He believes that if "immediate experience" like sensations, is susceptible to being misperceived, thus resulting in erroneous inferences for epistemic agent (as is very common in everyday life) then it doesn't make sense to think of acquaintance as a necessity for knowledge.
Instead, Sellars emphasizes the need to dispel the myth by closely examining the “form of the givenness”, dissecting the proposed operations of acquaintance in terms of “such facts as that physical object X looks red to person S at time t, or that there looks to person S at time t to be a red physical object over there.” (Sellars) Sellars asserts that acquaintance theory has not been sufficiently evaluated, and that in order for the theory to be validated, the range of sense impressions it claims can be "given" to the epistemic agent must be fully accounted for by an "exhaustive list", and each type of impression must be meticulously scrutinized as a prospect for such givenness.
Conee argued that when Mary the neuroscientist first sees a red object, she doesn't gain new information but rather "a maximally direct cognitive relation to the experience.
"[2] Michael Tye makes similar use of the distinction between acquaintance and factual knowledge in his analysis of the Mary thought experiment.
Richard Fumerton views direct acquaintance (the theory of which he often refers to as “classical foundationalism”) as simple, hence indefinable.
He concurs with Russell that the acquaintance relation between the individual's awareness and a state, object, fact, or property obtains in a way that cannot be reduced to more basic operations.
He suggests that one potential benefit of acquaintance, or “the given”, is that it solves the problem of infinite regress of justification for beliefs by serving as the basis on which all inferences can be grounded.
Skeptics reject this proposal, arguing that in “the given” would need to be propositional in order to ground inferences, or, at minimum have its own truth value.
Skeptics who find Fumerton's response unsatisfactory persist that having a truth value requires employment of concepts, i.e., comparing, classifying, and making judgments.
That process involves at least the simplest of beliefs associated with memories of previous experienced, making acquaintance a form of inference.
He also posits that for an epistemic agent to establish acquaintance unavoidably engages a proposition, or at least requires categorizing of inputs.
In his “Object and Person” (2002), Roderick Chisholm examines the conflicting perspectives between philosophers on whether or not we can actually be directly aware of the contents of our experiences.
Chalmers contends that as acquaintances is understood as separate from cognition, it does not seem feasible as justification for beliefs or as a basis for knowledge.
Sellars resolved the problem simply by asserting that naturally the speckled hen experiment fails to support an acquaintance relation because the individual cannot reasonably be expected to build up such an association where the total number of objects in an array cannot be known without methodically accounting for them all.
He points out that the “character of the experience” is not distinguishable to the individual's subconscious in such cases of instant presentations of complex arrays of data.