For what can be known about God is plain to them, because God has shown it to them.
Ever since the creation of the world his invisible nature, namely, his eternal power and deity, has been clearly perceived in the things that have been made. (Romans 1:19-20)
“There came to St. Anthony in the desert one of the wise men of that time and said: ‘Father, how can you endure to live here, deprived as you are of all consolation from books?’
Anthony answered: ‘My book, philosopher, is the nature of created things, and whenever I wish I can read in it the works of God.’”