The distinction between identifying reference and uniquely existential assertion is something quite undeniable. The sense in which the existence of something answering to a definite description used for the purpose of identifying reference, and its distinguishability by an audience from anything else, is presupposed and not asserted in an utterance containing such an expression, so used, stands absolutely firm, whether or not one opts for the view that radical failure of the presupposition would deprive the statement of a truth-value. It remains a decisive objection to the theory of Descriptions... that... it amounts to a denial of these undeniable distinctions.

Strawson (1964) "Identifying Reference and Truth-Values", Theoria Vol xxx; As cited in: Paul Snowdon (2009) "Peter Frederick Strawson", The Stanford Encyclopedia of Philosophy.

Peter Frederick Strawson (Stanford Encyclopedia of Philosophy/Fall 2009 Edition)[plato.stanford.edu]