In Science and Poetry (1926), I.A. Richards provides and exact formal
definition of pseudo-statement in poetry:

"A pseudo-statement is a form of words which is justified entirely by its
effects in releasing or organizing our impulse, attitudes " and responses. "
a statement is on the other hand justified by its truth, i.e, its
correspondence, in a highly technical sense, with the fact to which it
points".

NB. In relation to poetry (written by poets), Richards draws this
distinction between prepositional statements (which aim solely to express
truth about the external worlds) and PSEUDO-STATEMENTS (of poetry) (which do
not) to posit a deeper opposition between poetic language and entities
(emotive, unverifiable) and scientific language (detonative, verifiable).

The function of poets and poems is not to supply a REPERTOIRE of verifiable
facts or entities but to impart a perfect emotive description of a state of
mind or of a supposed being.

What separates the truth of pseudo-sentences and pseudo-individuals from
those of scientific statements and entities is its specialist ability to
organize experience, response, emotion, social interaction in richly
complicated and imaginatively stimulating new unpredictable ways. Consensus
is less difficult to be obtained in the former set of statements, the
non-pseudo ones.

The whole of pseudo-sentences and pseudo-entities (or pseudo-IDs) is
epitomized by this kind of extra-complex organization, production of
impulses (feelings?) and responses (feelings?) in the emotive utterance
(including the recent insults, obscenities, ect.. ect.)
 
Regards

Antonio Gonzales Y Perez