A recent study (loose use of the word) surveyed philosophers of religion, other kinds of philosophers and average people to find out what the most convincing arguments for and against the existence of God are.
The study also attempted to see what factors influence how people view an argument (e.g. atheists view arguments more negatively than believers do, gender, education, etc).
[From the paper]
Respondents were asked to rate how strong they found a series of natural theological arguments ,on a likert scale of 1 (very weak) to 5 (very strong). Arguments were organized in two groups(arguments for and arguments against the existence of God) of 8 items each. The results are summarized in figures 1,2,and 3 grouped in arguments for and arguments against. Overall, the strongest rated natural theological argument was the argument from evil (meanscore: 3.55). The second strongest rated argument was the argument from parsimony (mean score: 3.01), followed by the cosmological argument (mean score: 2.98). The argument from miracles and the argument from beauty were rated as weakest. The mean scores of the arguments are summarized in the bar chart on the existence of God.
Breaking it down
Believers (Theists), Atheists and Agnostics were asked to evaluate arguments both for and against God. It’s one of the reasons this study is interesting, no one really cares how strong you think the arguments on your own side, which you obviously support, are.
Lets break down one of the bars in the graph, say, the moral argument:
3.4 is the average score believers assigned to it.
1.41 is the average score atheists assigned to it.
1.93 is the average score agnostics assigned to it.
Arguments were asked to be rated on a five point scale, with one being “very weak” and five being “very strong”.
This graph shows the mean score for each category of arguments (So, say, the average score atheists gave for arguments for God OR the average score agnostics gave to arguments against God).
It’s no real surprise that believers rate arguments for God higher than non-believers. Likewise, non-believers rate arguments against God higher than believers do. Agnostics (as somewhat expected) occupy the middle of these two positions.
What makes the strong arguments strong?
This could probably warrant a study within itself.
The strongest argument for God, according to the survey, is the cosmological argument; it is not something that you can outright disprove either.
In the case of the cosmological argument by Aquinas:
-  There exists things that are caused (created) by other things.
-  Nothing can be the cause of itself (nothing can create itself.)
-  There cannot be an endless string of objects causing other objects to exist.
-  Therefore, there must be an uncaused first cause called God [From 1-3].
1 – 3 are almost uncontroversial to most people. I’m not a believer and yet i accept 1 – 3 as true.
For an argument to be good, first, the premises must be true. If you accept the premises but reject the conclusion that comes from them, you are simply being illogical (aka stupid).
However, if the argument is not valid, that is, you cannot actually draw your conclusion from the premises, you can reject the conclusion.
In this case, i do not think it is obvious from the premises that the first cause just has to be God because we say it is so. It could be anything, multiple Gods, an unthinking atom, some prior always-existing state of the universe, etc. God could very well be the first cause but he very well could not be either.
The strongest argument against God is the problem of evil. It is relatively hard to deny that bad things happen, especially when they happen to people who don’t at all deserve them. If God is all-loving, why does this occur?
Both these arguments go to the very root of what it means to be human and how we view our existence. Where did all this come from? and Why do bad things happen?
That’s why i think they are both strong.
While it is interesting to see the strongest and the weakest, I am more interested in the level of agreement or disagreement. Even if the problem of evil is the strongest, this just could arise from atheists rating it very highly and distorting the average. It only really works if the person you are trying to use it against also thinks it is strong.
Whilst this is not included in the study, i quickly worked out the degree people disagree over particular arguments.
The largest disagreement over ratings was over the Moral argument, followed by the argument from miracles. So, one side found it much more or less convincing or strong than the other.
In the case of miracles, we can see why atheists might disagree with this, most of the miracles, their proof is by the Bible or the Quran, but they do not believe in those books. Seems automatic. They might not even believe it is possible for God to work miracles.
The most agreement (aka smallest disagreement) was found in the Problem of Evil, followed by an almost double as large gap, by the Argument from Divine Hiddenness.
Why do both sides believe these? I am not really sure.
Religious people are people just like atheists. They care about all the suffering in the world, they are compassionate, and they are charitable.
Christians are also always told God is the God of love and kindness.
If this is true, why does he let bad things happen? I think this speaks to everyone.
Hiddenness also ties into that, why does God seem to do nothing? Why are miracles so abundant, seems like an almost daily occurrence in in the bible but now the supply of those types of miracles seems to have suddenly dried up?
If God wanted us to believe or be good, why doesn’t he come down and do it constantly?
That sort of thing i guess. That also might be the reason why people disagree over the argument for miracles, miracles constitute anything BUT hiddenness.
Here is one last graph, it shows the two most agreed (green) and two most disagreed arguments (red) in each category.
What does everyone think about why the results are the way they are?