Socratic irony is feigned ignorance, and feigned belief that one's interlocutor knows the truth about something, in order to provoke discussion and advance the search for truth. Practised by Socrates in the Platonic dialogues, this term has become widely used to describe the practices of other philosophers whose method is analogically similar to that of Socrates in the dialogs.
For example, it is often said that Søren Kierkegaard practised Socratic irony, because his major aesthetic works were written under a variety of pseudonyms, and it is clear that Kierkegaard would not agree with all the positions taken by these pseudoauthors. In fact, the pseudoauthors sometimes even comment on one another (cfMetafiction), so it could be said that there is some form of dialog in Kierkegaard's work.
Irony is a form of utterance that postulates a double audience, consisting of one party that hearing shall hear and shall not understand, and another party that, when more is meant than meets the ear, is aware, both of that "more" and of the outsider's incomprehension.
Socraticirony involves a profession of ignorance that disguises a skeptical, non-committed attitude towards some dogma or universal opinion that lacks a basis in reason or in logic.
The expression "irony of fate" stems from the notion that the gods (or the Fates) are amusing themselves by toying with the minds of mortals, with deliberate ironic intent.