When Thomas Jefferson sat down in Philadelphia during the summer of 1776 to draft what would become the most famous document in American history, he drew heavily from a philosophical tradition that had been building for over a century. The Declaration of Independence did not invent its ideas — it crystallized them.
The Lockean Foundation
John Locke's Second Treatise of Government (1689) established the framework that Jefferson would adapt. For Locke, all human beings are born with natural rights — rights that exist prior to and independent of any government. These include life, liberty, and property. Governments, Locke argued, are formed by consent of the governed precisely to protect these pre-existing rights. When a government fails in this duty — or actively violates those rights — the people have not merely the right but the obligation to alter or abolish it.
Jefferson translated this into the immortal second paragraph of the Declaration:
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.
Note the substitution: Jefferson replaced Locke's "property" with "the pursuit of Happiness." Scholars debate the reasons — some suggest Jefferson followed George Mason's Virginia Declaration of Rights, others that he sought a broader formulation. Either way, the Lockean architecture remains unmistakable.
"Self-Evident Truths"
The phrase "self-evident truths" is doing considerable philosophical work. Jefferson was not simply asserting popular opinion. He was invoking the Enlightenment tradition of natural law — the idea that moral truths about human nature can be known by reason, without appeal to revelation or tradition alone.
This was a radical claim in 1776. Most political orders on earth rested on hereditary authority, divine right of kings, or simple conquest. To assert that all men possessed equal natural rights by virtue of their humanity alone was to challenge every existing monarchy simultaneously.
The Tension at the Founding
The Declaration's promise was not immediately fulfilled — most obviously in the institution of slavery, which Jefferson himself practiced. This tension was apparent to contemporaries and has never been fully resolved. But the document's words created a standard against which American practice could always be measured — and found wanting.
Abraham Lincoln understood this when he cast the Civil War as the nation finally living up to its founding promise. Martin Luther King Jr. understood it when he appealed to the Declaration in Letter from Birmingham Jail.
Why It Still Matters
The natural rights tradition embedded in the Declaration provides a basis for individual liberty that does not depend on government permission. Rights, on this view, are not granted by the state — they are recognized and protected by it. This distinction is foundational.
It means that when a government claims to expand rights by granting new entitlements, it is engaged in a fundamentally different activity than when it honors pre-existing natural rights. Both may be defensible, but they are not the same thing, and conflating them distorts our understanding of what rights actually are.
As we mark 250 years since Jefferson's pen scratched across parchment in Philadelphia, the natural rights tradition remains the deepest root of American liberty.