Why is it that while Europeans were talking about freedom and self-government, they were increasing the practices of slavery and colonization?

One of the more difficult paradoxes of the Enlightenment was that it coincided with an escalation in the practice of slavery, with people such as Thomas Jefferson espousing the virtues of human liberty while keeping their fellow humans in bondage. What impact did the Enlightenment have on racism? How does the Enlightenment relate to slavery? Why is it that while Europeans were talking about freedom and self-government, they were increasing the practices of slavery and colonization?