Academic Skepticism

The claim

No impression carries a mark that guarantees its truth. Nothing can therefore be known with certainty, and the wise course is to withhold assent while acting on what is persuasive.

What it held

The strangest thing about Academic scepticism is its address. This is Plato's Academy, arguing for two centuries that knowledge is unattainable — and its members claimed to be recovering the real Socrates, the one who knew that he knew nothing, from beneath the doctrines later attached to him.

The target was the Stoic theory of the cognitive impression: the claim that some perceptions are so clear they could not have arisen from anything but their object. Arcesilaus and then Carneades argued that for any such impression an indistinguishable false one is possible — the identical twin, the dream, the wax seal that cannot be told from its pair. If no impression is self-certifying, assent is never safe.

The obvious objection is that life then becomes impossible, and Carneades answered it with a theory of the persuasive: impressions can be more or less credible, and can be tested against one another, without any of them ever amounting to knowledge. That is a theory of reasonable belief without certainty, and it is the school's most durable contribution.

How it argued

Arguing against whatever is proposed, on either side, without asserting a position — the practice Cicero calls in utramque partem. Carneades famously argued for justice one day and against it the next before the Roman senate.

What it was arguing against

Stoic epistemology above all, and the whole idea that any school possesses a criterion of truth.

Where it disagreed with itself

Whether the sceptical Academy held its position dogmatically — the Pyrrhonists said it did, and that asserting nothing can be known is itself a claim to know something. Philo of Larissa's late softening split the school and produced Antiochus' return to dogmatism.

Common misconceptions

That it is the same as Pyrrhonism. The Academics allow degrees of credibility and act on them; the Pyrrhonists regard even that as conceding too much. And it is not a rejection of Plato but an interpretation of him — arguable, and argued.

How it began

Arcesilaus became head of the Academy around 266 BCE and turned it from doctrine to dialectic, reportedly because he thought Plato's dialogues were about questioning rather than teaching.

What became of it

Ended when Philo's successor Antiochus declared the sceptical phase a mistake and returned the Academy to positive doctrine. Sulla's siege of Athens in 86 BCE finished the institution.

Lasting influence

Cicero's philosophical works are Academic, and they were how the ancient debates reached the Latin Middle Ages and the Renaissance. Augustine's first surviving book is an answer to this school.

Why it still matters

Carneades' account of the persuasive is an early theory of graded justification, which is roughly where epistemology arrived again in the twentieth century after trying alternatives.

Put another way

Two wax seals from different rings, side by side, with no way to say which made which impression.

Where to start

Cicero's Academica, with the caveat that he is on one side of what he describes.

The surprising bit

Carneades came to Rome on an embassy in 155 BCE, gave a brilliant speech defending justice and an equally brilliant one demolishing it the next day, and Cato had him sent home before he corrupted the young.

In their own words

Connections

Answers

Old Academy

Opposed by

Early Stoicism

Parallel to

Pyrrhonian skepticism

The verdict

Plato's school spending two hundred years proving that nothing can be proved, and doing it well.

Sources

• Stanford Encyclopedia of Philosophy