Propositions belong to science or to everyday intelligence. Russell concurred with much of the preceding during this century's late teens and early twenties. He agreed that propositions are pictures of reality and that elementary propositions, reflecting atomic facts, are logically independent of one another. He was persuaded by Wittgenstein that the propositions of logic and pure mathematics were simply tautologies. Russell held with Wittgenstein that a proposition can represent a fact because the proposition is made of words signifying objects and their conditions.
Perception falls within knowledge by acquaintance.
All knowledge is a relation, for Wefald as for Russell, between a person and the object of the knowledge. Perception is such a relation. Whereas Russell thought the objects of perception, the objects of immediate acquaintance, to be sense data, Wefald holds the objects of perception to be concrete material objects. Another sort of knowledge by acquaintance is memory. In acquaintance we know not only objects, but relations and structures.