Although the opening line of the Gettysburg Address invokes Declaration of Independence language, Lincoln makes a slight change: he calls the principle that all men are created equal a “proposition” instead of a self-evident truth as Thomas Jefferson did.
Why did Lincoln make this change?
A proposition denotes a proposal of some sort – something that can be true or false, accepted or rejected. Whereas, a self-evident truth is always true – it is obvious once you’ve been enlightened to it. By making this change to the language of the Declaration, Lincoln may be recognizing the change that has taken place in the American Idea from 1776 to 1863. Americans began as “one people” in 1776 by asserting that all men are created equal; now, in 1863, many claim that we are no longer one people and that the principle of equality is not a self-evident truth but a proposition, a self-evident lie. Many, north and south, have rejected the proposition of equality. By making this change to the language of the Declaration, Lincoln seems to be asking fundamental questions about the nature of the American Idea: Are Americans still “one people”? Do we still hold these truths to be self-evident?