To the uninitiated, advertising is full of Mad Men-esque mystery, but as a writer and creative lead, I'm here to tell you that advertising is just fancy persuasion. At its most fundamental, an ad is trying to get you to think, feel, or do something, usually purchasing a product. Advertising often takes cues from the world of rhetoric and communications, including concepts like ethos. A little bit of rhetorical theory can unlock why some ads work and others fall flat. Ethos in advertising refers to the general vibe or culture of a time or place, but for our purposes, we're looking at it as a form of persuasion. The ancient Greeks are where we get many foundational theories around persuasive communication, and Aristotle believed good rhetoric often took three forms: logos (appeal to intellect), pathos (appeal to emotion), and ethos (appeal to authority). Ethos in advertising means that a brand is convincing the audience that they know what they're talking about—that you can trust them. It creates instant connection and trust with the audience, gives them a reason to listen to the ad, and clarifies the message. It builds a loyal brand following by telegraphing reliability and credibility, which are important cornerstones of any successful brand with strong brand advocates. Ethos doesn't always have to be obvious, and it can be established through various means such as featuring a subject matter expert, using statistics, or establishing the brand as the expert. Some ads use ethos strategically to make an ad more convincing, while others rely on deceitful practices. Ethos is powerful but needs to be balanced with other forms of persuasion, such as logos and pathos, to feel authentic and believable.