Paul Graham posted this in the summer, which included this quote that I want to comment on today:
"I sometimes ask students what their position on slavery would have been had they been white and living in the South before abolition. Guess what? They all would have been abolitionists!"
Graham's essay uses this quote to make the point that unless you are an "aggressive independent-minded" type, that is, not predisposed to either conformity or passivity, you are unlikely to have been an abolitionist.
I think there is a simpler analysis. Why not instead list what actions an abolitionist of the time - Harriet Tubman, Frederick Douglass, Sojourner Truth - would take if alive today? It would be pretty easy to take that list of actions, compare it to your current life, and get a rough idea of whether you would have been an abolitionist in those days.