The idea of a god may be lunacy but it is not impossible. Whether I am evil or not is unknown as I we all strive to gain pleasure and evade pain, therefore all action are evil and good or neither. So we can assume that the definitions for good and evil are not abstract enough to be considerred viable for usage.
I am an agnostic-atheist. Though nothing is for certain, even this statement. So I may not be, though due to the lack of evidence to suggest otherwise, other than the fact that people can lie and I may being here and amongst other relevant scenarios, to believe otherwise is lunacy.