Sorry for the delay. Wasn't feeling well.
OK, then, let's just go with, "No, I am not sure. Is my lack of certainty sufficient reason to declare that they do in fact exist?" Especially when the stakes are so great.
Since you ask:
My religious background is Christian-Protestant, specifically Wisconsin Synod Lutheran (fundamentalist evangelical). Like most, I was brought up in my parents’ church and, essentially, inherited my religion. My loss of faith began quietly, when I first read Lawrence and Lee's "Inherit the Wind," a play about the Scopes "Monkey Trial." It didn't really make an impression at the time, which was fortunate since this was during my junior year at a synod high school. It was, however, my first substantive exposure to a non-biblical view of the universe. From there, one thing led to another over the years and decades. I noticed as things went along that it was getting more difficult to have meaningful religious discussions, as my correspondents usually fell back on dogma, doctrine, and even the outright fantastic in response to my arguments and questions; questions spurred by discrepancies I noticed between what I could see and what I’d been taught to believe. I think the seminal moment came when I first saw a presentation of the PBS series "Cosmos," with Carl Sagan. It wasn't an epiphany, but it did give me a framework within which I could begin to assemble my doubts into a coherent whole, and a base from which I could begin searching for answers.
With the advent of the computer and the internet, I finally had a way to find and connect with others like myself. It didn't take long, though, to notice that most of my free-thinking friends were downright hostile to the very idea of god, any god, as well as to all religious believers. Richard Dawkins' books "The Root of All Evil" and "The God Delusion" became their bible and doctrine. I use those words on purpose; to me, there is no visible difference between the fundamentalist believer and the "fundamentalist" atheist. The rhetoric, fervor and reliance on dogma appear the same; the only major difference is that the believers' patronizing is replaced by the atheists' invective. I've always felt that it was easier to talk with a friend than with an enemy, even if only to exchange ideas with no intention of converting the other person to my point of view, so I try to reject confrontation as a matter of course.
Then I read another work by Carl Sagan: "The Varieties of Scientific Experience; Notes on the personal search for God," which is actually transcripts of Sagan's Gifford Lectures at Glasgow University in 1985. What immediately struck me was a remark in the Forward by the book's editor and Sagan's widow, Ann Druyan, regarding Sagan's treatment of his audience: "...what remains with me was his extraordinary combination of principled, crystal-clear advocacy coupled with respect and tenderness toward those who did not share his views." If I ever had an epiphany in this whole process, this was it; my immediate reaction was "Yes!" And then there was the book itself, laying out observable and testable arguments why the predominant Western notion of a personal creator deity is at least insufficient and at best unlikely. Since then, I've taken Carl Sagan as my model. He's not perfect and he has his hobby horses, but I find him so much more palatable than I do Dawkins. I believe it's possible to disagree with everything Sagan says and still enjoy the read.
Speaking of Sagan, I just re-read his preface to "Varieties" and was reminded that there are two types of religion, natural and revealed. Revealed religion is, of course, that which is derived from holy writ, to include teachings, commentaries and all other additions and supplements. Natural religion Sagan understood to mean "everything about the world not supplied by revelation." I would define it more specifically as the idea that humans have an inbred albeit vague knowledge of God and a desire to seek him out. Neither believers nor atheists spend much effort distinguishing between the two types, with the result that arguments about God and Religion often become intermingled and confused.
Hi. Hope you're doing well.