Aristotle set out to answer exactly that question over 2,000 years ago

with the Treatise on Rhetoric.

Rhetoric, according to Aristotle,

is the art of seeing the available means of persuasion.

And today we apply it to any form of communication.

Aristotle focused on oration, though,

and he described three types of persuasive speech.

Forensic, or judicial, rhetoric

establishes facts and judgements about the past,

similar to detectives at a crime scene.

Epideictic, or demonstrative, rhetoric

makes a proclamation about the present situation,

as in wedding speeches.

But the way to accomplish change is through deliberative rhetoric,

or symbouleutikon.

Rather than the past or the present,

deliberative rhetoric focuses on the future.

It's the rhetoric of politicians

debating a new law by imagining what effect it might have,

like when Ronald Regan warned that the introduction of Medicare

would lead to a socialist future spent telling our children

and our children's children what it once was like in America when men were free.

But it's also the rhetoric of activists urging change,

such as Martin Luther King Jr's dream

that his children will one day live in a nation

where they will not be judged by the color of their skin,

but by the content of their character.

In both cases, the speaker's present their audience with a possible future

and try to enlist their help in avoiding or achieving it.

But what makes for good deliberative rhetoric,

besides the future tense?

According to Aristotle, there are three persuasive appeals:

ethos,

logos,

and pathos.

Ethos is how you convince an audience of your credibility.

Winston Churchill began his 1941 address to the U.S. Congress by declaring,

"I have been in full harmony all my life with the tides which have flowed

on both sides of the Atlantic against privilege and monopoly,"

thus highlighting his virtue as someone committed to democracy.

Much earlier, in his defense of the poet Archias,

Roman consul Cicero appealed to his own practical wisdom

and expertise as a politician:

"Drawn from my study of the liberal sciences

and from that careful training to which I admit

that at no part of my life I have ever been disinclined."

And finally, you can demonstrate disinterest,

or that you're not motivated by personal gain.

Logos is the use of logic and reason.

This method can employ rhetorical devices such as analogies,

examples,

and citations of research or statistics.

But it's not just facts and figures.

It's also the structure and content of the speech itself.

The point is to use factual knowledge to convince the audience,

as in Sojourner Truth's argument for women's rights:

"I have as much muscle as any man and can do as much work as any man.

I have plowed and reaped and husked and chopped and mowed

and can any man do more than that?"

Unfortunately, speakers can also manipulate people with false information

that the audience thinks is true,

such as the debunked but still widely believed claim

that vaccines cause autism.

And finally, pathos appeals to emotion,

and in our age of mass media, it's often the most effective mode.

Pathos is neither inherently good nor bad,

but it may be irrational and unpredictable.

It can just as easily rally people for peace

as incite them to war.

Most advertising,

from beauty products that promise to relieve our physical insecurities

to cars that make us feel powerful,

relies on pathos.

Aristotle's rhetorical appeals still remain powerful tools today,

but deciding which of them to use

is a matter of knowing your audience and purpose,

as well as the right place and time.

And perhaps just as important is being able to notice

when these same methods of persuasion are being used on you.