They're probably lesser giants than the Enlightenment writers and philosophers who inspired them. It should be noted that of the Founding Fathers (John Adams, Benjamin Franklin, Alexander Hamilton, Thomas Jefferson, James Madison, George Washington), Hamilton was openly opposed to the institution and trade of slavery, never owned one in his life. John Adams never owned slaves.
Benjamin Franklin did at one point, but became president of the Pennsylvania Abolition Society and in the last year of his life, petitioned Congress to ban it. Jefferson was a fucking monster tbh, huge intellect and small character. No comment on Madison, he's the Father of the Constitution and author of the Bill of Rights.
In May 1794, in a letter to Tobias Lear, George Washington expressed that he wanted to liberate his slaves, referring to his ownership of people as “repugnantly to his own feelings.” He knew that the values that he had been fighting for as a revolutionary were incompatible with slavery. He also knew that his own legacy would be affected by the position he took on that issue.
Although Washington didn't have control over the freedom of the Custis slaves, he did stipulate in his will, which he wrote in July 1799, how his own slaves should be treated.
“I do hereby expressly forbid the sale, or transportation out of the said Commonwealth, of any slave I may die possessed of, under any pretence whatsoever,” he wrote.
Washington added that he expected the former slaves “shall be comfortably clothed and fed by my heirs while they live.” He further instructed that his younger slaves be provided for until they were 25 and should be taught an occupation and learn how to read.