Hume saw problems using facts to justify morals. Learn about Hume’s Guillotine and where reason fits in morality!
Hume’s “A Treatise of Human Nature” - http://www.gutenberg.org/files/4705/4705-h/4705-h.htm#link2H_4_0004
GE Moore’s “Principia Ethica,” a text that puts forward a similar argument by different means - http://fair-use.org/g-e-moore/principia-ethica/s.13
A list of philosophical responses to the is/ought problem - https://en.wikipedia.org/wiki/Is%E2%80%93ought_problem#Responses
Related THUNK episodes:
https://www.youtube.com/watch?v=3EebMeEo91c https://www.youtube.com/watch?v=xu6kkLJ58Z0 https://www.youtube.com/watch?v=xdfiRfvH10k