Debates between atheists and theists over the existence of God are common, but really good and productive debates are rare. Im not talking about the formal, professional debates between trained debaters; Im talking about more personal and private debates serious discussions between serious people. What can be done to improve their quality and ensure that time isnt wasted?
The more you assume about the other person, the more likely it is that some of your assumptions will be wrong; that in turn leads to mistakes, misunderstandings, and missed opportunities. As much as possible, ask questions rather than simply making assumptions. Dont assume that you know their religious doctrines. Dont assume that you know their philosophical beliefs. You can make guesses, but try not to act on or base much on them.
In addition to not making assumptions about what the other person believes, you also shouldnt assume that they share with you how to define key terms and concepts. If they dont, then arguments you make using these concepts wont be as effective and may be counterproductive. The biggest issue to get out of the way is the definition of the God itself. Unless everyone is operating from the same definition of this, theres no point in even starting.
Not only will people differ in how they define key concepts, they will also differ in the sorts of premises they rely upon. These different premises will cause you to examine the same arguments and evidence in completely different ways. In fact, it may be that the real discussion you should be having is not over these arguments and evidence, but over the premises and assumptions themselves.
There are few things more annoying that someone who offers for evaluation and critique an argument which they themselves dont rely upon and which, if false, wouldnt affect their position. This suggests that they only care about getting you to agree but not why which means they dont care about believing for good reasons. Theres no sense in wasting time with such a person. Insist on arguments which they find convincing and which if undermined would cause them to reconsider their belief.
There is no sense in even beginning a discussion if you have no plans or means for supporting your beliefs and defending the claims you intend to make. A mere statement of belief serves as nothing more than a psychological self-report and almost no one will care about that. To get people to care, you must articulate sound reasons for your beliefs and this entails supporting your claims. Unless you can do this, dont bother starting.
Not every attempted defense of ones beliefs is equal. Some defenses are better than others and what separates the good from the bad is ones ability to use sound logic and reason. The better you are at constructing a logical argument, the better you will be able to defend your claims as well as critique the claims made by others. Insist on this not just from yourself, but also from others. If their logic is poor, you wont get anywhere.
There is a tremendous difference between discussion and preaching. Discussion is a give-and-take process where everyone contributes something. Preaching, however, is just one person getting up on a soapbox and haranguing others until they get tired enough to walk away. People who enter discussions with the intention of preaching are disingenuous in their actions and should be cut out of the conversation.
If you enter a conversation unwilling to reconsider your position and uninterested in the possibility of learning something new, they you are too closed-minded to help the conversation be productive. More likely than not, youll just end up preaching. You probably wont learn anything and others wont learn from you. A little humility here when it comes to what you think you know can go a long way.
Some may question why anyone would bother to debate the existence of God in the first place. Most theists seem to see this as an opportunity to evangelize, with only few claiming that faith must come as a gift from God and cannot be produced through reasoned argument. A larger number of atheists question the value of such arguments, insisting that too many theists arrived at their beliefs through non-rational means and if thats the case, what reason is there to think that their minds will be changed through the use of rational argument?
Theres definitely something to this. If a person hasnt reasoned their way into a position, its unlikely that they can be reasoned out of it and a reasoned discussion like this has little value unless all enter into it with a willingness to consider the possibility that they may learn something new and have to change their minds. In a significant number of cases, then, the arguments might just be a waste of time thats why several of the above suggestions provide things to watch for in order to determine who is worth continuing with.
In a few cases, though, it might still be worth engaging in at least something of a discussion with someone who isnt as reasonable and rational as youd prefer. Sometimes you might be able to show a person how to reason well. Its not uncommon for people to hold unreasonable positions simply because they dont understand how to reason properly. Sometimes, you might be able to plant a seed of doubt and thereby get them to engage in greater skepticism of their position somewhere down the road you probably wont see it, but it may happen.
Finally, there may be some value for you in that you will learn more about aruging. Even if you have no hope that the other person will help you get anywhere with regards to the substance of the discussion, they might serve well as a bad example and allow you to practice identifying fallacies and finding the flaws in an argument.

