Facebook CEO Mark Zuckerberg faces his toughest task this week—to persuade lawmakers and the public that he takes privacy seriously and will implement the steps necessary to restore the public’s trust after recent privacy issues has shaken confidence in the platform.

Persuasion, by definition, is the act of presenting arguments to move your audience to action or to change their beliefs or attitude. It’s exactly what Zuckerberg will be attempting to do this week—move his audience to change their attitude about Facebook after it was revealed that millions of users saw their data shared improperly.

Persuasion skills are absolutely critical for today’s leaders, and especially for Zuckerberg as he faces tough questions. It is no longer enough to make a popular product; contemporary entrepreneurs must play the role of advocate and politician—navigating a minefield of regulators, competitors, and changing consumer behavior and tastes.

As a student of persuasion for the past quarter-century, I can tell you that leaders who win hearts and minds are often those who follow Aristotle’s 3-part formula of persuasion that the Greek philosopher created down more than 2,000 years ago. From the Declaration of Independence to the most influential speeches in modern history—inspiring writers and speakers have all followed the formula.

Aristotle’s Three Modes of Persuasion

Aristotle believed that rhetoric—the art of persuasion—required both wisdom and eloquence. Persuasion, he argued, cannot occur in the absence of elements, or what he called “appeals.” They are: ethos, logos and pathos. A convincing argument must include all three components.

1. Ethos. Ethos refers to the credibility of the speaker. Aristotle believed that audiences found a speaker to be trustworthy if the speaker had three characteristics: wisdom, virtue, and goodwill. A speaker must be seen as a person of high integrity and morality to viewed as credible and trustworthy.