A computer-implemented filtering method comprising: receiving a set of propositions, each comprising a respective linguistic description expressed by a respective user; forming an input matrix of lexical components vs. propositions, wherein rows in the input matrix represent the propositions and columns in the input matrix represent lexical components in the respective descriptions; performing a matrix factorization on the input matrix to reveal latent clusters of the lexical components and/or propositions; filtering the set of propositions based on one or more of the latent clusters; and outputting a result of the filtering to a target user.