And thats an answer to a question i had posed previously.
If someone who doesnt know <insert deity here> (not meant to belittle, but this is a general question) and lives a life that is not a "Sin" to their beliefs, but is a "Sin" to yours, are they "Sin"ning ¿
Then they are not sinning. St. Paul tells us to follow our consciences, and for a Christian, the goal would be to form the conscience toward Christ and His teachings. For those who do not know His teaching, then they would simply follow their consciences and be judged according to that.
That is only my opinion, BTW, not doctrine.