That is, the mind can perceive what is truly right. Once one reflects on that truth he cannot deny it thus making the truth self-evident. The first self-evident truth states that all men are created equal. Jefferson, being a student of political theorist John Locke, perceived all men as equals in the sense that they are equally free. This does not imply that all men are equal in their talents and intellectual faculities.
All men are free based on the commonality of their humanity.
Thus humanity is the only requirement. The meaning of Jefferson's wieldy statement of equality came under speculation in 1857, eighty-one years after its birth, during the court case of Dred Scott v. Sanford. Scott was a slave who questioned whether his residence on free soil had changed his status as a slave. Consequently, Chief Justice Roger Taney raised the question whether Scott, a slave and a person of color, had the right to sue in a federal court of law. To answer this question, Taney went back to Jefferson's words in the Declaration.