Start with the Ten Commandments to get an idea of his character. Also, the fruits of the Spirit of God (in us) can be found in the 5th chapter of the book of Galatians in the New Testament.

However, those depending on science may have a more difficult job experiencing the reality of God.

It’s about relationship, too, a larger topic in many ways. Can you know someone you don’t have a relationship with? Or, can you have a relationship with someone you don’t know? The latter does not seem to be the most likely.