Justification The tendency to believe that two wrongs make a right. The effort to make something unjust appear just by blaming outside causes.
"I am a Vietnam veteran, so it's understandable that I snap at people."
Sometimes justification has a retributive quality:
"I was mean to her because she looked at me funny."
Rationalization Rationalization is the effort to make something that is wrong seem right. It is more fanciful and convoluted than justification.
"Sure, I took his money, but he would have wasted it anyway."
"I flunked out of school, but a degree wouldn't have helped me get a job anyway. It's hopeless out there."
Projection Projection is the tendency to infer that all evils are external. More specifically, it is the unconscious tendency to associate one's own evil tendencies with others.
A selfish person thinks: "Everybody out there is selfish. No one will take care of me, but me. Therefore, I have to look out for number one."
A dishonest person thinks: "You can't believe anything anyone says."