I've spent a lot way too much time talking to non-Christians about the same issues over and over again, and I wind up having to repeat many points, clarifications, and explanations. I therefore decided to try and make a compendium of some of these things that I can refer people to as opposed to having to retype the same arguments from scratch every time I talk with a new person.

This post has to do with morality and is aimed at people who don't believe that objective moral values need God to exist. We can frame the issue by asking the following questions: are the moral values and duties we hold dear and guide our lives by just social conventions, like what side of the road we drive on? Or are they merely expressions of personal preference, like having a taste for certain foods? Or are they somehow valid and binding, independent of our opinion, and if they are objective in this way, what is their foundation?

To be clear about a few things:

• Moral value refers to the worth of a person or action, whether it is good or bad.
• Moral duty refers to our obligation to act in a certain way, whether that action is right or wrong.
• By objective I mean independent of human opinion. For example, the laws of nature hold whether we acknowledge them or not, so they are objective.

Now, traditionally moral values have been based in God, who is the highest Good. But if God does not exist, what is the basis of moral values? In particular, why think that human beings have moral worth? 

Moral duties have also traditionally been thought of to spring from God's commandments. But if there is no God, what basis remains for objective moral duties?

If God does not exist, why think that we have any moral obligations to do anything? Who or what imposes these moral duties upon us? Where do they come from? It’s hard to see why they would be anything more than a subjective impression resulting from societal and parental conditioning.

Thus, people who claim that some things are just objectively wrong need to answer the above questions, or they need to say there is no such thing as objectively wrong.

I'll end this with something I personally believe:

1.  If God does not exist, objective moral values and duties do not exist.
2. Objective moral values and duties do exist.
3. Therefore, God exists.