Hebrews 11:1 (NKJV)
Now faith is the substance of things hoped for, the evidence of things not seen.
Faith in God is not a belief in a fairy tale. It is based on reason and on rational evidence. But it is not like God has written on the sky "I am God, and you are not." So why does God hide behind his creation and behind the logic and reason of our minds? It seems that he is hidden to those who do not believe and that he is obvious and manifest to those who do believe. Belief is an interesting concept when compared to knowledge. Do I know something to be true because I have seen it, touched it, or measured it the way a scientist would? Or do I know something because I have an inner voice, an unexplained peace, a vision which sees the miracle of creation, or best of all a changed life.
Hebrews 11:6 (NKJV)
But without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him.
God wants us to believe by faith and not by our physical senses. It is as if faith is a spiritual sense supported only by our mind and not by our physical senses. God wants it this way. At our core being we are spiritual not physical. Jesus said those who worship Him must worship Him in spirit and in truth.
As it turns out, faith, which is a gift of God, is more real than the physical world. I think one day we will be surprised at what this world we live in is really like compared to eternity. It is just the shadow of the far more real thing.
2 Corinthians 4:18 (NIV)
So we fix our eyes not on what is seen, but on what is unseen. For what is seen is temporary, but what is unseen is eternal.