God reveals Himself to human beings by chosen witnesses. Sin has left us naturally blind to spiritual things and strangers to God. Blindness leaves a person dependent on the testimony he receives from credible witnesses. This is exactly where we find ourselves in respect to the knowledge of God.
Now, it is true that every person on his pilgrimage through life encounters many conflicting witnesses. Lies are all about us as well as truth. Far more of the ideas and beliefs that we encounter than we would ever imagine are essentially spiritual. They are directly or indirectly giving us a concept of what God is like. Whether we will believe in the true God or the popular lies of this world is the great issue of life and eternity.
But God has set before us many clear voices testifying of Him. The material universe with its incredible complexity, beauty, and immensity is one such witness, a witness to its Creator - or rather a collection of witnesses too numerous to count. They are physical in nature, but they testify of the existence, power, wisdom, immensity, and goodness of the Eternal Spirit that made them. And it is you, the individual that must deal with this testimony to a Creator, with all the profound implications of being yourself His creature.
The theory of evolution is a denial of essential truth about God, masquerading as a science. Science has its place, but God has not given the world a special class of men whose theories rule our spiritual lives. He has given us a universe of evidence and made each one of us capable and responsible to come to right conclusions. The fact of creation is important for everyone to grasp since it is foundational to understanding our responsibility to obey and honour His laws.
We cannot know everything about God from this witness, but it is a starting place. "For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse" (Romans 1:20).