Human beings seem to have a propensity for religious experience.
I do not believe this propensity is sufficient reason to infer the existence of God. The rationalist in me says that it is probably some adaptation hardwired into the human psyche by evolution hundreds of thousands of years ago in order to cope with the overwhelming profundity of consciousness.
The problem for me is that what science knows about the workings of the human mind pales in comparison to what it doesn’t know. Science can’t tell us exactly how this spiritual propensity in man developed. More importantly, science can’t presently tell us that religion still does not fill some important psychological need. So while I am fully sympathetic with the more militant atheists like Sam Harris, Richard Dawkins, and Christopher Hitchens when it comes to all the evils that have been perpetrated in the name of one religion or another, I don’t think that they have come close to establishing that all mankind would be better off without any religion.
I do not believe that belief in God is inherently irrational, but I do think that rationality suffers when religions, sects, and denominations insist upon objectifying what are subjective spiritual experiences. The inability or unwillingness to distinguish between understanding founded on empirical observation and understanding based on religious faith is what I find troubling.
I realize that none of this may actually be relevant to whether I am an atheist or an agnostic. It does, however, leave me in doubt about whether there is anything to be gained by affirming that God is non-existent rather that merely acknowledging that God is unknowable. Since resolving those doubts is not a particularly high priority in my life right now, I think I think I will remain more comfortable under the label “agnostic.”