For those who prefer proof to faith
Faith is belief that is not based on proof.
And sometimes a proof, or disproof, cannot be found.
In those instances, faith is our only option.
In science, our knowledge of the universe is growing but still severely limited. How much of the universe we are actually aware of, we don't really know. (And most of us are too egocentric to admit that we don't know.) Cosmic energy seems to be mainly 'dark energy' (73%) and 'dark matter' (23%). This is the stuff that is believed to hold the universe together and accelerate its expansion, but mankind has not yet identified the nature of this energy and matter. The remaining 4% consists of atoms and molecules that can be identified by mankind (or rather, a clever subset of mankind).
In medicine, following the invention of the microscope in the 17th century, microbiologists have studied diligently to understand the nature of bacteria. But even after 300 years, they admit to only having studied perhaps 1% of earth's microbes.
Since man can only understand only 4% of the nature of matter, and since man can only understand 1% of the nature of microbes, (and since man cannot understand the nature of women at all!) how can anyone claim to fully understand the nature of God?
What we can do, and this is really simple to understand, is to love God and to love one another. And the Cross shows us the most perfect example of love that can ever be discovered. See the meaning of the Cross.