I just read the assignment for class (Rosenstand p. 127-140), and I believe that this is so far the most convincing theory that I have read to date. Psychological egoism is true to almost everyone that I know. We as human beings do tend to always think about "what's in it for me?" In addition, according to the professor, a good theory must be able to hold an argument. For example, if you were to save, someone from drowning it does not necessarily mean that you are a compassionate person; you could be thinking (sometimes subconsciously) that it makes you feel good to help someone, which means that you did in fact save that person for self-gratification. If you look at ethics through psychological, egoism even mother Teresa was doing all that good for herself.