Theists: What is the most compelling argument you have heard for Atheism?

[SteveII]

No, more like:

1. The fine-tuning of the universe is due to either physical necessity, chance, or design.

2. The fine-tuning of the universe is not due to physical necessity or chance.

3. Therefore, the fine-tuning of the universe is due to design.

Before you jump on any of these, remember that the argument is an inductive argument: in which the premises are viewed as supplying strong evidence for the truth of the conclusion.

It's also a disjunct syllogism, the -least- reliable form of valid argument, even if the premises -are- sound, that doesn't conclude "god".  I'm not sure why you think it's all that useful, even if you think it's true.  Would you also accept this valid argument?  

The fine tuning of the universe is due to either design, chance, or neccessity.
The fine tuning of the universe is not due to design or chance.
Therefore the fine tuning of the universe is due to necessity.

I'm just trying to gauge your level of confidence in the form of the syllogism.  

I never addressed necessity. My understanding is that the laws of physics do not dictate the constants we are discussing, so they each could have been different over a fairly wide range.  Therefore they are not the way they are due to necessity. 

In your version, you would need to have reasons why design as less likely than the others.