Joe Carter over at Evangelical Outpost has an interesting discussion of atheism triggered by the claim made by several of his correspondents that atheism is an epistemological default position, i.e. unless the theist can provide proof that God exists, or at least provide good reasons for believing that He does, the atheist is justified in believing that He does not. In other words, the burden of proof is on the one who affirms an existential proposition, it's on the person who affirms the existence of something.
Since we cannot prove that God exists, and since we cannot offer compelling evidence that He exists, the atheist is justified, he claims, in believing that there is no God and in holding that belief until such time as the theist can offer evidence to the contrary. The problem, as Carter points out, is in deciding what will count as reasonable or satisfactory evidence:
In the case of entities such as God, whether evidence is reasonable or compelling will often depend on the inner state of the observer's "heart". The individual who wants there to be a God will find certain arguments and evidence more persuasive than will the person who does not want God to exist. That is, the mind will embrace what the heart desires and will reject what the heart disdains. This is what Blaise Pascal had in mind when he said that "the heart has reasons that reasons cannot know."
For example, someone hopeful, but perhaps doubtful, of God's existence might find the plethora of biological information and irreducible complexity in the biological realm much more persuasive of the existence of a transcendent mind than someone who is hostile to the notion that such a being exists. One who would welcome the reality of a Creator might be more inclined to see Aquinas' cosmological argument as plausible even if it's not a proof in the strict sense, whereas one who would not be at all happy with news of God's existence would argue that since it's possible to quibble with one of the premises of the argument he's therefore justified in rejecting the whole thing.
Evidence and arguments are person-relative. We see this in our responses to recent arguments justifying the invasion of Iraq. Many people who are inclined to support the Bush administration found their arguments persuasive. Those who were disinclined to support the current leadership were unconvinced. How one reacts to the facts depends in large measure upon how one feels about what they entail.
The fact that two people can view the same facts and come to different conclusions illustrates that there is a non-logical component to our reasonings, and it is this non-rational aspect of our noetic structure that people are referring to when they talk about Faith. Belief in God is primarily a matter of the heart and secondarily a matter of reason. The person who does not want God to exist will never be persuaded that He does, even "should they see someone return from the dead," as Jesus put it. On the other hand, a person who is open and receptive to God's existence will find ample warrant for believing that He does.
Again, Pascal put it well. He said, "There is enough evidence to convince anyone who is not dead set against it." The corollary to that is that no amount of evidence would convince one who is dead set against it.
