Immanuel Kant said that a human being’s innate practical reason gives rise to a universal set of “moral laws” which any rational person knows they must follow. 

 But even if we know the universal laws, why should we feel compelled to follow them? Kant’s answer was that we m...

This claim argues that we have no ethical obligation to act well beyond what makes us personally happy or satisfied. This seems extremely close to making ethics purely subjective. 

Philosophers, like Nietzsche, argue that a person truly concerned with their ‘self’ w...

Sidgwick argued that it is happiness that we should take as the motivation for being good. So if happiness was what was intrinsically good, we must, at times, even put our own desires aside to maximize the greatest happiness for the greatest number of people. But what might motiv...

This claim(adopted by authors like Sam Harris) argues that we should use the tools of modern science to assess what human beings want and what their characteristics are, for instance, by looking at evolutionary biology or psychology and develop an ethical framework in accordance with human na...

David Hume observed that we can never move readily from scientifically understanding facts about the world to determining what values people should hold to. It became clear that just knowing objective facts about human nature and desires couldn’t necessarily lead us to a clear se...