Logos, ethos, and pathos
Barack Obama’s Selma speech is dominated by ethos (appeal to trust and authority) and pathos (appeal to emotions), but we can also find some examples of logos (appeal to logic). Sometimes, these modes of persuasion are mixed, for example when Obama mentions the founding documents of America and the values they promote. In this case, he uses both ethos, as he appeals to these documents’ authority, and pathos, as he seeks to stir the audience’s emotions toward these values.
Logos
The speaker appeals to logos when he makes logical connections between ideas or when he mentions facts that support his views.
For example, he alludes to the Civil Rights Movement to support his idea that the Selma march represented an important part of the American fight for freedom and equality: “The march on Selma was part of a broader campaign that spanned generations; the leaders that day part of a long line of heroes.”. By using the phrase “long line of heroes”, Obama also creates ethos, as he suggests the respect he has for the leaders of the Civil Rights Movement.
To support his idea that unity can create change, Obama gives factual examples and shows the social change brought about by the Selma march and by similar events: “Because of campaigns like this, a Voting Rights Act was passed.”
...the change (…) is visible here today in the presence of African-Americans who run boardrooms, who sit on the bench, who serve in elected office from small towns to big cities; from the Congressional Black Caucus to the Oval...