This question could be interpreted in several ways:.
- “How is it that we have (a) God?”
This is taking the question literally, but this question is unanswerable, for the following reasons:
First, if “god” is that who made all things out of nothing, which I think we have to presuppose as a basic definition for “god”, then we definitely cannot “have god” per se. God would be infinitely greater than we are. We can’t have god. God has us, for the simple fact that god made us.
- “How is it that there is a “god”?”
This question is also unanswerable. If god exists, then god would have definitely existed before there was anything. The proper question would rather be how come we exist, and not how come god exists, because our existence would be predicated on God’s existence. God needs to exist for us to exist. Conversely, if we exist and there are other things in the universe, then either there is a non-rational explanation for existence, or God has to exist.
I say “non-rational” explanation, meaning that creation can be satisfactorily explained to be a product of a random process, since any design or rational process would lead to the necessary condition that order is guiding the creation of the universe, which in itself requires a rational Being to sustain it, since there is no known rational force in the universe other than rational beings. Nature in itself is chaotic, random and irrational.
- “How is it that we come up with the idea of “god”?”
This is interpreting your question’s “god” is an idea. But this question is futile, because if “god” is as I defined earlier, then necessarily we either have to come up with a non-rational explanation for reality, or that God is a reality; nay, god would have to be the only reality, since this god would be the Creator of all things, including time and space.
So, technically, we don’t come up with the idea of God, if God is real; it would rather be that because God is real, necessarily we would find His footprints all over nature as well as within our own heart.
If God is not real, then this question is mute, since it has no meaning.
- “How do we know that God is real?”
This I think is the only interpretation of your question that is viable. Logically speaking, we can argue the following way:
– as discussed above, either there is a Creator God, or we must have a non-rational reason for creation to exist.
– however, non-rational processes cannot produce the kind of systematic and orderly progress from Big Bang to planets to life to rational creatures. It is a natural law that the measure of chaos must increase unless sustained by external force. Evolution cannot explain it. There must be a rational mind to create design in the universe.
A second line of reasoning is the reality of Jesus.
– Jesus was a real historical person.
– He claimed to be God Himself.
– This claim is either true or false.
– If false, he either knew it was false or he didn’t.
– If he didn’t, he was a lunatic, and a very miserable one for he died for it.
– If he knew it was false, then he was the worst of liars; he would be down right evil, considering the situation the Jews were in. But he was also not a successful liar, for he also died for it.
– Or thirdly, it was true, and he knew it, then He was God, and God exists. God truly came among us, lived among us as one of us, died for our sins, and rose to give us eternal life.
– Now given Jesus’ life, nobody in the entire human history ever doubted the authenticity of his teachings. Many might have reduced his miracles, but none would equate him as lunatic or evil. His words and deeds simply were not those of a lunatic or an evil liar.
– That left us with the only possibility, however incredible it may be, that He is indeed who He claimed He is, God.