In philosophy, an aporia (aporíā) is a conundrum or state of puzzlement. In rhetoric, it is a declaration of doubt, made for rhetorical purpose and often feigned.
In philosophy, an aporia is a philosophical puzzle or a seemingly irresoluble impasse in an inquiry, often arising as a result of equally plausible yet inconsistent premises (i.e. a paradox). It can also denote the state of being perplexed, or at a loss, at such a puzzle or impasse. The notion of an aporia is principally found in Greek philosophy, but it also plays a role in post-structuralist philosophy, as in the writings of Jacques Derrida and Luce Irigaray, and it has also served as an instrument of investigation in analytic philosophy.
Plato's early dialogues are often called his 'aporetic' (Greek: ἀπορητικός) dialogues because they typically end in aporia. In such a dialogue, Socrates questions his interlocutor about the nature or definition of a concept, for example virtue or courage. Socrates then, through elenctic testing, shows his interlocutor that his answer is unsatisfactory. After a number of such failed attempts, the interlocutor admits he is in aporia about the examined concept, concluding that he does not know what it is. In Plato's Meno (84a-c), Socrates describes the purgative effect of reducing someone to aporia: it shows someone who merely thought he knew something that he does not in fact know it and instills in him a desire to investigate it.
In Aristotle's Metaphysics, aporia plays a role in his method of inquiry. In contrast to a rationalist inquiry that begins from a priori principles, or an empiricist inquiry that begins from a tabula rasa, he begins the Metaphysics by surveying the various aporiai that exist, drawing in particular on what puzzled his predecessors: "with a view to the science we are seeking [i.e., metaphysics], it is necessary that we should first review the things about which we need, from the outset, to be puzzled" (995a24). Book Beta of the Metaphysics is a list of the aporiai that preoccupy the rest of the work.