What two "big philosophical questions"
does jefferson's ownership of slave raise?

Thomas Jefferson, a man of great contradictions. He was one of the Founding Fathers of the United States but he was the owner of slaves.

One question would be:  Are really all humans equal by nature? Men´s natural-born rights of life, freedom were only applicable to white people and not to black slaves.

Second question: Can you hold that men can improve their destiny by their own actions but keep slaves who are deprived of the realization of their own will at the same time?

Explanation:

the main reason that the constitution did not proclaim all men to be free and equal is because of the issue of slavery.