Three things determine what we believe.
1) The language we speak
2) The ideas we consume (books, movies, music, conversation)
3) What our senses perceive (hear, tasted, touch, smell, but mostly see).
The last one is easiest. We either see things or we don’t. What we see we believe. We see a rock and we believe that rock exists. We touch it. Maybe we lick it. But our senses sense something and we accord that something as real because we sense it. This is a powerful paradigm. The inverse of this paradigm is that if we can’t sense it, maybe it does not exist because our personal and physical faculties for determining reality cannot verify it.
Second, none of reason up from a blank slate. This is a conceit of enlightenment thinkers who proposed a tabula rasa — a blank slate — upon which reality could be reasoned from. Nothing could be further from the truth. Even the idea of a blank slate becomes an idea that frames how we think reality should be. And, of course, all the ideas we have been fed in our lifetime about our origin and destiny frames our worldview. If our parents told us about God, we believe in God. If our schools replace that belief with a believe in a “natural” order that excludes a creator, then that becomes what we believe. We are easily swayed and constantly evangelized by our culture. If we consume books and magazines (National Geographic) and TV shows that presume the chance existence of a universe that somehow ordered itself over time — then we believe it unless there is some countervailing message. Evangelism actually isn’t that difficult when you conceive of it is telling people what to believe. It is just that the Christian view of the world is so at odds with the prevailing and overwhelming message that comes from schools, universities, movies, magazines and books. But volume does not equate to truth.
Finally, the language that we speak is the fundamental framework for our conception of reality. Our language is the reach and limit of our logic. Words and our linguistic world limit what can be real to us. Where there is an extra-rational reality (love or sorrow or regret) we seek to find words to approach them rationally — to bring them under our intellectual control.
Accurate language yields a logical framework. We are unable to logically think about something for which we cannot find words.
Some languages are better than others at rationally approaching the world. English may be wonderful, but one cannot create a rational framework for space flight with English (or French). We need other languages — such as calculus — a wholly unique language by which we can rationally approach, describe, and harness the “laws” of physics.
The point is that our rationality is not as precise as presume it to be. When we rely upon our senses alone we cannot know the past or future, nor radio waves or even the far side of the moon, let alone God.
What we read become our intellectual universe — that corpus of literature (or TV and movies) extends or limits the possibilities of reality in our minds. A framework a literature devoid of God will not yield a belief in God. A framework of God will yield a belief in God.
Finally, language itself is our link to rationality and logic — and we have little control over the languages we speak.
In the end, humans are always finite creatures unable to comprehend our universe from an external point of view. We are anchored, intellectually, to what we sense, read, and the language we speak. We are finite creatures wholly incapable of rationally deducing a God’s eye perspective of the universe and time and space and life. As such we are rendered creatures of faith operating in an intellectual vacuum from which we cannot escape except through faith.