Benjamin Franklin was a colonial scientist and political theorist who based his ideas and scientific applications within Enlightenment era thinking. Benjamin Franklin certainly encouraged a shift from religion-based to a reason-based society. For years, Franklin did not fully embrace his own thoughts and writings, however, as he owned two enslaved people for many years before he embraced and actually practiced abolitionist principles, and finally released the two people he had held hostage.
In the 1750s, Franklin embraced the Enlightenment era principles of individual freedom and reason-based thinking that understood slavery to be the highest contradiction of enlightenment concepts. He began petitioning through the Society for Promoting the Abolition of Slavery, for full abolition, and for full support of recently freed black people.
Franklin came to understand that religion-based thinking in colonial America often justified slavery through superstitious justifications. However, white supremacist scientists in the 18th and 19th centuries often attempted to justify slavery with pseudo-science. Scientists like Franklin, however, believed that reason-based societies would lead to more just and free societies for all people. Certainly, religion-based societies such as the puritan societies of the northeast colonies bolstered oppression, particularly based on race and gender. Dominant religion-based societies often embrace hierarchy among people due to the inherent hierarchy of worshiping the conception of a "superior" divine being.