Thank you for a very interesting and well written philosophy article. I took notice that you are an atheist. I too am an atheist at heart, and an agnostic at mind. Although I won't be able to contribute with different theistic arguments, I'd like to make a general statement about the discussions surrounding the existence of God and also to comment on each of the three arguments you have presented.
God is an ill-defined concept, and the vast majority of the discussions surrounding the existence of God are either plagued by semantic inconsistencies between the two sides or just plain meaningless. In the first case, people which engage in the debate start from different definitions of god and either keep comparing apples to oranges or end up discussing the definition itself. In the latter case, people assume god to be ineffable or transcendental in nature, in which case the discussion is meaningless because the existence of something which is totally untenable and disconnected from the physical world is not only untestable, but also effectively equivalent to it not existing at all for all practical purposes.
Regarding the cosmological argument, it is undoubtedly one of the strongest arguments in favor of some ultimate first cause for everything, which could be called "god", in order to solve a problem of infinite regression. I, however, like to follow a little epistemic principle called Ockham's razor (or the law of parsimony), which essentially tells us that the best explanation is the one which, with the fewest and simplest assumptions, can explain the widest range of phenomena. In this particular case, it appears to me that the simplest assumption is that there is no first cause, but simply that existence is equally and infinitely extended into the past and into the future. Causality drives change within existence, but not the origin of existence itself.
Regarding the moral argument, I don't consider it to be a strong argument for the simple fact that I don't believe in moral objectivism. From everything that we know about the universe, the only parts of it which have any sense of morality are conscious (within a varying degree) living beings. The universe is fundamentally amoral, with the morality that we are used to being a convenient social construct for the successful organization of growing groups of people. There is no need for god as the source of morality because there is no objective morality in the universe.
Finally, my views on the fine-tuning argument are related with my views on the cosmological one. Within an everlasting existence, multiple iterations of universes are perfectly feasible. Of course, only those whose parameters are "finely-tuned" will have an appreciable duration and will give rise to the conditions for life and consciousness to evolve. It is perfectly possible that other iterations have completely different values for those natural constants; it's that most of them give rise to universes within which no form of life is able to evolve in order to analyze those universes from the inside like we do with ours.
I'd like to end my comment by noting that my cosmological view is neither original nor scientifically proved. But it offers a much simpler frame to interpret both the infinite causal regression and the apparent fine-tuning of our universe's natural constants than to assume any ill-defined deity concept which is either incomprehensible or irrelevant from our standing.
Sorry I'm coming to this post so late after it was published...
Concerning your thoughts about the moral argument: This means that there is no inherent transcending "value" in anything? The life of a 3 year old child is ultimately no more valuable than fecal matter. If my daughter is raped and killed, I can find solace and comfort in knowing that my feelings are social constructs. I should just fuhgedaboudit.
I admit, I am referring to emotionally charged situations because I am programmed to. It just seems to me that if I believed this way that you describe, no objective morality, that since there is no value in anything, I would live for my own personal gratification only. Squeeze all the pleasure I can out of life and go out with a bang. Nothing we do matters except for a short period of insignificant time on this planet. That means rape, steal, kill, lie, cheat, if it makes me happy in any given moment. Nike: Just do it. Know the consequences and risks to future pleasure potential, but just do whatever you want. Sure, people will be hurt in the process, but none of that matters in time. All that matters is me and my pleasure.
Is this consistent with your position?