“As an aid to the conceptualizing process, men select from the total content of the concept a few characteristics; they select the ones that best condense and differentiate that content at a given stage of human development. Such a selection in no way shrinks the concept’s content; on the contrary, it presupposes the richness of the concept. It presupposes that the concept is an integration of units, including all their features.”
— Leonard Peikoff, “O.P.A.R.”, pages 102-103.
(There is a lot that is wrong in Kant’s conclusion that “There must exist synthetic a priori judgements.”, but the “synthetic” part of it is due to a faulty theory of concepts, one that conflates a concept’s definition with its content.)
I don’t partake of Ayn Rand’s (and Leonard Peikoff’s) animosity toward Kant. Yet his theory makes no sense at all to me.