Source: p 175, French prepositions à and de in infinitival complements, A pragma-semantic analysis (2008) by Lidia Fraczak, as part of Adpositions ; Pragmatic, semantic and syntactic perspectives (2008) edited by D Kurzon, S Adler
Concerning the verbs considered as “presupposing” by Adamczewski (1991), it may be observed that what is presupposed by V1 is not always V2 itself but some stage preceding the one represented by V1. Thus, the verb commencer (“to start”) presupposes the stage “to envisage”, “to plan”; the verb continuer (“to continue”) presupposes the stage “to start”; the verb finir (“to finish”) presupposes the stages “to start” and “to continue”; and the verb oublier (“to forget”) presupposes the stage “to think of ”. This kind of presupposition can be called “lexical” and it may be distinguished from “situational” presupposition, where the use of some V1 requires that the fact expressed by V2 be presupposed.
Some verbs seem to be related to both types of presupposition: for example, oublier in “oublier de + V2” (“to forget to + V2”), on one hand, presupposes the stage “to think of ” and, on the other hand, it will be used in a context where the fact expressed by V2 is presupposed as well.
Other verbs, however, while containing “lexical” presupposition, do not require “situational” presupposition. It is the case, for example, with the verb essayer (“to try”) (considered as “presupposing” by Adamczewski), which does presuppose some previous step or stage (“to think of ” or “to plan”) but whose use is not necessarily determined by a presupposition about the fact expressed by V2. Statements like the one below:
(4) Un prisonnier a essayé de s’évader cette nuit de la prison X.
‘A prisoner tried to escape from prison X last night.’
do not allow us to consider that the piece of information related to V2 (“to escape...” in this case) is necessarily presupposed.
I do not understand the (bolded) last sentence above. How does essayer de NOT presuppose the prisoner's escape? The prisoner must have presupposed the possibility of escape before trying it?