For an introductory lesson, listen to a lecture about Abu Ghraib prison and how good people “turn evil”:

http://www.ted.com/talks/lang/eng/philip_zimbardo_on_the_psychology_of_evil.html

Combibe this with  some great quotes on conscience to set you thinking, on this site:

http://quotes.liberty-tree.ca/quotes/conscience

An introductory handout, based more on religious views, go to:

http://www.tere.org/assets/downloads/secondary/pdf_downloads/ALevel/ConscienceNotes.pdf

For an excellent, more advanced article discussing Kant and conscience by Professor Allen Wood of Stanford University, in the context of a threefold classification (conscience as theories of moral knowledge, motivation and reflection) go to:

http://www.stanford.edu/~allenw/webpapers/KantOnConscience.pdf

The Catholic catechism on conscience, deeply influenced by Aquinas, go to:

http://www.catholicity.com/catechism/moral_conscience.html

Former Treasury secretary Paul Roberts inveighs against the US use of torture:

http://www.counterpunch.org/roberts05282009.html

If you’re thinking of becoming a lawyer, what do you make of the US Supreme Court’s “Shock the conscience” test of illegality?

http://law.jrank.org/pages/10268/Shock-Conscience-Test.html