I've been watching some discussions between Christians and atheists -- not participating in them so much -- which follow the pattern: atheist asks: How can Christians believe X, followed by fruitless discussion. Followed, incredibly, by many more discussion which are exactly the same, including the exact same X.
One popular X lately is: How can God be 3 different people?
The answer seems clear to me: if God is omnipotent, he can be as many different people as he wants to be.
I used to believe that God existed and that he was omnipotent. I don't believe anymore that God exists, but it seems to me that if you believe He does and He's omnipotent, that pretty much explains any other questions anyone might have have about Him. Certainly including: How can He be 3 different people. Omnipotent means God can do anything. He can be 5 different people if he wants to, or 1000. Or 2/3 of one person. He could change from one of those numbers to another and back again much more quickly than you could blink an eye. In the same amount of time he could destroy the entire universe, make another one exactly like this one is right now after having developed for billions of years, and then get rid of that one and make a slightly different one, and get rid of that one and make one in which there are people much more intelligent than humans on every planet, and each one has 5 hands and 3 feet, and then get rid of that one and make another one, and so forth, billions or googolplexes of times in a billionth of a billionth of a second, and still make it seem as if the universe was more than 13.8 billion years old and the Earth was more than 4.5 billion years old and had contained living organisms for 4 billion years, or anything else which any of us could or could not imagine, because "omnipotent" means he can do anything, period, and being 3 people at once is far from the most amazing thing He could do.
That's what I was taught as a Christian child. Maybe other Christians don't believe exactly the same as that, I don't know.
Now, to me, a much more pertinent question seems to be: If God exists, why does He hide himself from atheists?
The theists, of course, have a stupid answer prepared and just waiting for that question: "He does show Himself to you all the time, you're just ignoring Him. Look at that tree! Now how can you say there's no God?!"
Which is why I don't go around asking my question even though it seems more pertinent to me.
How do you change a theist's mind about the existence of God? Now THAT'S a good question! I have no idea how to do it. After after several years' worth of contact with New Atheists, I have much, much less desire to do it. These days, without having come to regard God's existence as one bit more likely, I think about converting to Catholicism or Islam just to make it even clearer that I'm not a New Atheist. I've been an atheist since the mid-1970's. These days, after a lot of contact with New Atheists, I often start to cringe when I hear that someone's an atheist.