An epitrope is defined as, “a figure of rhetoric, consisting in granting something that one can dispute, in order to give more authority to what one wants to persuade” (Littré, Epitrope), S. Concession.
Under ordinary conditions, as described by Grice’s principles, the arguer refutes everything possible, and concedes anything else. So, “Peter concedes P” pragmatically implies that Peter is not able to refute P. If the arguer concedes a doubtful proposition, he or she will be considered a bad arguer; if he or she concedes something that could obviously be refuted, the speech will be interpreted as being ironic:
P is obviously wrong:
L: — P, okay, but / yet Q
Embedding P in a concessive structure, assigns P to the opponent, whether or not he or she wishes to endorse it:
About a writer whose qualities of style have just been discussed in a rather negative way:
I am ready to consider him a good stylist, but he doesn’t know what a plot is.
Irony may also arise from the exaggeration given to the granted position:
I may have visions, but I also have some hard evidence.