In her “HeForShe Speech”, Emma Watson uses all three forms of appeal, with a preference for ethos and logos.
Generally defined as appeal to reason, logos means using logical arguments, facts, or statistical evidence to support one's case.
Emma Watson frequently draws on statistical evidence to make the audience realise why the issues of gender roles and gender equality are urgent: “I’ve seen young men suffering from mental illness unable to ask for help for fear it would make them look less ‘macho’—in fact in the UK suicide is the biggest killer of men between 20-49 years of age;” (ll. 74-77); “…it will take 75 years, (…) before women can expect to be paid the same as men for the same work. 15.5 million girls will be married in the next 16 years as children.” (ll. 119-123)
The effect of using logos is that it makes the audience more likely to accept her call to action and her arguments because it proves they are supported by facts. In general, Watson's arguments are clearly laid out and explained in a logical way: “If men don’t have to be aggressive in order to be accepted women won’t feel compelled to be submis...