1. Enlightenment thinkers viewed it as "a violation of people's natural rights".
2. American and French revolutionary pronouncements about liberty and equality also focused attention on people's rights.
3. Quakers and Protestant Evangelicals said slavery was "repugnant to our religion".
4. Slavery wasn't necessary for the economy (England and New England=slave free) so slavery was considered out of date and unnecessary.
5. Slave rebellions indicated that slaves weren't "contented" with their life and people were appalled by the brutality with which they were repressed.
6. Britain's abolition of slavery caused other nations to follow suit due to its leading economic and military power.,
