Purpose is defined as the reason for existence. Unless there is a Creator/intelligent Designer, there can be no reason. Nature doesn't operate under reason. When people seek purpose for their lives, they often add comments such as, "why was I put here?" and "what am I supposed to do?" Clearly they are seeking real purpose. Psychology doesn't talk about real purpose, psychology talks about getting a feeling (or sense) of having a purpose. If you do something that earns you praise, it will typically give the feeling of having fulfilled your purpose. Helping other people will earn you praise, at the very least, self praise. At some point in our lives we will see that all we are doing is chasing feelings. When Richard Dawkins was promoting his book, "The God Delusion", he was interviewed by Jeremy Paxman on a British station. At the very end of the interview, Dawkins was asked if he was comfortable (in his philosophy) and Dawkins responded " I am comfortable with that but even if I wasn't it wouldn't change what I believe because I don't believe were put here to be comfortable". People long/crave to be part of a plan or design that is larger, higher, more significant than heir own happiness or comfort. I don't see where science has anything to do with purpose. I think Christianity tells us that God has offered to adopt us as His sons and daughters in a bond of supernatural love, and for those who desire God, to seek Him and He will reveal Himself. We can seek Him by trying to obey His command to love one another and love your neighbor for where love is, there God is also.
