Logos

Not that Jefferson isn't down with some good old-fashioned emotional pathos, but for the most part the form of rhetoric he uses is logos.

He presents clear reasons why the colonies are declaring independence, including a cause-and-effect explanation and specific offenses for evidence.

People have natural rights, he argues, which government was created to protect. This government is not only neglecting its purpose, but is doing a whole bunch of other bad things on top of that, so obviously we have to declare independence. Cause: government not doing what it's supposed to do. Effect: we declare independence from that government.

How logical.

Government, Jefferson writes, is an institution that derives its power "from the consent of the governed," a.k.a., those people with "unalienable Rights" to "Life, Liberty and the pursuit of Happiness" (2). Because of that fact, Jefferson says, "whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government" (4).

Makes sense, doesn't it? The people create the government to serve them, therefore they have the right to replace it when need be.

Moving past the most famous part of the document, Jefferson proves the failures of the British government:

The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States. To prove this, let Facts be submitted to a candid world. (8-9)

Not only does Jefferson state that the government has wronged the people, he sets out to demonstrate exactly how by continuing with a specific (and lengthy) list of evidence. He doesn't make vague, angry claims with nothing to back it up, there are at least twenty-seven specific examples given to support his accusation. No one can say T.J. wasn't thorough.

Now, Jefferson wasn't all logic and reason, he lets some pathos sneak in there. Phrases like "all men are created equal," "mankind are more disposed to suffer, while evils are sufferable" (5), and "absolute Tyranny" (8) certainly appeal to the more emotional side of the audience.

Whose heart doesn't flutter a little bit at that famous opening line of the second paragraph? There's no shame in admitting it.

Jefferson also later describes how the British people were "deaf to the voice of justice," (44) which is a pretty dramatic way to say they didn't respond to a letter. Next time you ask someone for a favor and they ignore you, tell them they were "deaf to the voice of injustice"—and if you just get weird looks, though, you didn't get the idea here…

Jefferson adds in elegant, dramatic phrases here and there to inspire the reader to support the argument that the colonies must be independent, but overall the document is pretty calm, cool and collected. He uses logical arguments with clearly delineated evidence to support his argument, meaning that the primary rhetorical device in the Declaration of Independence is (drum roll, please) logos.