Editing Knowledge by acquaintance (section)

===''The Problems of Philosophy''===
The distinction between knowledge by description and knowledge by acquaintance is developed much further in Russell's 1912 book, ''[[The Problems of Philosophy]]''.<ref name=Problems>{{cite book |last1=Russell |first1=Bertrand |title=The Problems of Philosophy |date=1912 |publisher=Williams & Norgate |location=London}}</ref>

Russell referred to acquaintance as "the given". He theorized that certain familiarities develop from an individual's experience with various primary impressions (sensory or abstract) that are so much a part of awareness itself that the individual possesses knowledge of these familiar features without accessing memories by the cognitive process of remembering. Russell believes that acquaintance is necessary in order for us to form any proposition—that any belief we form must be composed entirely of experiential components with which we have acquaintance. Per Russell, all [[Foundationalism|foundational knowledge]] is by acquaintance, and all non-foundational (inferential) knowledge is developed from acquaintance relations.<ref name=Problems/> Russell's famous description of acquaintance is as follows:

::We shall say that we have acquaintance with anything of which we are directly aware, without the intermediary of any process of inference or any knowledge of truths. Thus in the presence of my table I am acquainted with the sense-data that make up the appearance of my table—its colour, shape, hardness, smoothness, etc.; all these are things of which I am immediately conscious when I am seeing and touching my table. The particular shade of colour that I am seeing may have many things said about it—I may say that it is brown, that it is rather dark, and so on. But such statements, though they make me know truths about the colour, do not make me know the colour itself any better than I did before so far as concerns knowledge of the colour itself, as opposed to knowledge of truths about it, I know the colour perfectly and completely when I see it, and no further knowledge of it itself is even theoretically possible. Thus the sense-data which make up the appearance of my table are things with which I have acquaintance, things immediately known to me just as they are.<ref name=Problems/>{{rp|73–74}}

Russell adds that we have acquaintance with sense data, desires, feelings, (probably) the self, and universals like color, brotherhood, diversity, etc. Other acquaintance theorists would later suggest that we can have acquaintance with basics such as “yellow or not yellow”; ourselves; states, properties, things, or facts (Sellars, see below); feeling, sensations, ticklings, afterimages, itches, etc. (Chalmers, see below); necessary truths (such as “the tallest thing is the only thing that is as tall as it is”, “all violinists are musicians", "3 + 2 = 5", etc.); phenomenal experiences “seemings”;{{clarify|date=June 2020}} and sensory inputs, or “particulars that are directly present to the mind”.{{clarify|date=June 2020}}

Direct acquaintance only refers to the individual's direct access to some aspect of her/his experience, whereas knowledge by acquaintance requires that the individual have a belief about it. Russell and other acquaintance theorists assert that not only does acquaintance make knowledge possible; it makes thinking itself possible. This assertion is based on the epistemic principle that empirical experience is the source of properly simple concepts.

In ''The Problems of Philosophy'', Russell clarifies that knowledge we can have of a specific “so-and-so”, which is a thing identifiable as the thing that it uniquely is, is knowledge by description.{{clarify|date=June 2020}}

Per Russell, acquaintance knowledge is an awareness that occurs below the level of specific identifications of things. Knowledge by acquaintance is knowledge of a general quality of a thing, such as its shape, color, or smell. 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 also includes self-consciousness of one's having an experience. For example, "When I see the sun, I am often aware of my seeing the sun; thus 'my seeing the sun' is an object with which I have acquaintance." It is only possible to have acquaintance with things that exist, actual relata, according to Russell, and acquaintance does not involve thought, intention, or judgment, or application of concepts.

Russell allows for fallibility of acquaintance due to false impressions acquired in some acquaintance relations, and he argues that these do not negate the much greater number of accurate impressions that result in acquaintance based on truths. To support this position, Fumerton offers examples of error such as misidentifying a particular shade of color as another, and he suggests that acquaintance relations should not be viewed as guarantees of, but only as representations of probabilities of, truth relations.