For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, because that which is known about God is evident within them; for God made it evident to them. For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse. (Romans 1:17-20)
The gist is this: if you pay attention to the Creation you will learn about God, because the Creation reveals what God is like. Presumably you don’t even have to become a scientist to learn, because this God-knowledge is clearly seen. Neither do you have to become a Christian to learn, because the knowledge is already evident even to the ungodly.
So the question is this: Does everything in the Creation reveal God’s divine nature? Everyone can see what the natural world is like: there is beauty and bounty and birth, but there is also violence and indifference and death. There are also plenty of features in nature that just seem sort of neutral and impersonal and random. Is God like all these things? Or does God instill in everyone the ability to distinguish those features of nature that are like Him from those that aren’t?