Arguments for the existence of god

Apologetics
As long as there have been two or more people with differing religious views, there has been proselytism. This of course presents a problem; as religion is based on faith rather than evidence, logic, or reason, how does one go about convincing other people that their religion is the correct one? After all, if it's based on faith and not reason, your faith is by definition really no more a reasonable position than anyone else's. If you don't like what the church is doing, just form your own. You don't need evidence, just faith. As a result of this complete lack of evidence on what the true faith apparently is, there are over 1,000 denominations of Christianity alone, and no empirical reason to believe any of them.

Over the years, attempts to convert people to a particular faith have taken many different forms, most of them involving brute force and threats of violence - Convert or suffer the wrath of god's chosen people! This was fine up until about the end of the Dark Ages, with the adage that-

unknown source: "Creationism lost its best argument when the Catholic church stopped burning people at the stake"

After the enlightenment, the church started to have serious problems justifying its position. As science expanded our view of the world, God had fewer and fewer places to hide. Coupled with the fact that it was now considered slightly uncouth to simply torture and burn alive those that disagreed with you, the church and its parishioners now had to work very hard to justify their positions of belief, and harder still to convert others. Thus apologetics was born.

In a nutshell, apologetics is the discipline of attempting to justify a theological position through evidence, philosophy, science, metaphysics, and history. However, when these apologetics arguments are actually reviewed under scrutiny, we find they rely on: There are many conflicting arguments which attempt to support the existence of many conflicting gods. Being often mutually contradictory, they can't all be correct - but they can all be wrong. Indeed, every "argument" presented for gods thus far has one or more problems with validity or soundness. At their core, even the most seemingly persuasive apologetics are founded upon cognitive biases, magical thinking, logical fallacies, or basic unproved assertions, and the fact that theists of all stripes tend to use the same arguments for their specific god or gods speaks more to the common flaws in human thinking than it does to the usefulness of the arguments.
 * evidence so incredibly poor that even the apologists using it wouldn't accept such evidence as proof of anything in any other argument than for that of their personal god,
 * horrific straw man representations of true scientific theories,
 * convoluted metaphysics that ultimately have no real world underpinning, and
 * the distortion of historically documented events and evidence in a fashion similar in degree and irrationality to holocaust denial.

Definitions
It is important when engaging in an argument with a theist that all the required concepts involved in the argument are clearly defined; particularly the definition of God. Having clearly defined definitions prevents the theist from moving the goalposts mid-argument, or even more frustratingly getting to the end of the argument and then having the theists say “but that's not my god” or "that's not in my Bible".

Purpose of the argument
It is also important to make sure that the discussion is one that will be enlightening. An important question is, "what is the purpose of this discussion/argument?"

Prior to the onset of the hopefully dialectical discussion, both sides must reflect on the purpose and aim of the discussion. Argumentation will only prove to be fruitful if both sides are aware and accepting of the limits of persuasion in argumentation.

Religious people will almost never be "convinced" by any logically defeating counter-point, remaining staunch in their conviction, unless their faith is solely dependent on reason and proper logic. Therefore, it seems the appropriate middle-way seems to be to approach these discussions, on the whole, as forums for insightful discussion, rather than grounds for a conversion war, an approach that has proven and will continuously be proven to be ineffective in convincing religious theists to lay down their dogma.

It is important to consider the reason that successful logical arguments fail to convince theists is precisely that these theists were not convinced by logical arguments in believing in a divine being. It is usually based on personal experience, some subjective conviction that cannot be formulated into logical terms. It seems that even those who claim that their theistic belief is constructed upon some logically argumentative foundation, when pushed, eventually admit there is some fundamental subjective impetus for belief. However, if a particular theist maintains that they have a logical, objective foundation, but then dogmatically refuse to acknowledge the failure of his argument and are unwilling to question his theistic belief, then further communication is unnecessary and pointless.

Most common theistic arguments

 * First cause
 * Pascal's Wager
 * Argument from design
 * Argument from the meaning of life

Favorites of professional apologists

 * Ontological argument
 * Transcendental argument
 * Kalam
 * Evolutionary Argument Against Naturalism