One of the best ways to help theists understand atheism (if they are open to doing so) is to tell them that atheists believe in one less god than they do.
The only problem with this is that the existence of many religions and gods throughout history is nothing more that what we would expect in a world filled with a vast plethora of cultures, societies, and unique individuals within those cultures and societies.
Pointing this out tells us nothing about the truth claims relative to any particular religion. All it tells us is that there are many of them and there are many of them because human beings are highly intelligent, imaginative, and creative beings.
The claims of revealed religion are that God has communicated with mankind and that he communicates with any individual within that class upon certain principles and according to certain rules. We have access to him within the precincts of those principles. But why should we expect that any person or society, whether or not they (or some sub-group within that society) had access to him, or understood the principles, would not go ahead and create religious systems of there own in lieu of this? All cultures have their own art, architecture, philosophy, customs, mores, myths, cuisine, and any number of other things, so why then, is the presence of many religions evidence to doubt that at least some of what many of them are saying is true, or that there may be one true religion the truth of which can be accessed upon certain principles (if one could find it)?
I see no
logical reason to conclude that the existence of 1,000 religions precludes the existence of 1 divinely appointed true religion, or that each of the 1,000 could not contain truths of divine origin.
One may perceive
psychological reasons for this, and they may seem compelling, but I see no reason to believe that God does not exist because
x number of human societies have worshiped or do worshiped
n number of gods. One of them may be the true one. None of them may be. The point is that the fact that many gods are thought to exist and are inconsistent with one another provides no rational point of departure for the primary questions of religion, which is
does God exist, and, if so, how can I know it?
In other words, if Zeus doesn't exist, tough titty. Ditto for Cronus and Rhea, Apollo, Mercury, Wotan, Shiva, Demeter, Hecate, Innna, Allah, Huan Ti, or whoever. What I'm interested in is the God that does exist; If he exists,what he's like, and how I can communicate with him.
The existence of many religions and gods is a bare anthropological fact, not evidence of anything relative to those 'terrible questions" who am I, what is the meaning of my existence, and where am I going after this life is over that is at the center of the Church's messege.
The face of sin today often wears the mask of tolerance.
- Thomas S. Monson