The culture around us is materialistic, sensual, and naturalistic. We value and believe in what we can see, feel, and sense. There is something very grounding about the senses; when we feel connected to the world around us, we feel joyful, and in control, and so we strive to create "flowery bands to bind us to the earth" as Keats said in his poem, A Thing of Beauty. He said we seek "a sleep full of sweet dreams, and health, and quiet breathing" and that is the essence of the materialistic, naturalistic mindset. It isn't to say that we shouldn't want good things, but that we tend to seek and define goodness by what we can feel, because we are sensual creatures.
Is God real?
God, on the other hand, is a spiritual being. How do grounded, sensual beings perceive a spiritual being as "real"? How do we "feel" God in a way that is not completely ephemeral and unsatisfying? The Bible says that God's glory can be seen and perceived in nature (Psalm 19). There is something absolutely different about the natural world—it is an endless source of fascination for scientists (who want to know how things work) and artists (who want to understand beauty) and athletes (who want to interact physically with its structures and take on the challenges of giant mountains and giant ocean waves). We may assert, intellectually, that nature is an impersonal product of evolutionary processes, but we pursue nature with our emotions. And we know, intuitively, when we see a DNA helix, or the inside of a cell, or a delicate pattern in a flower, that these things are the result of design. And if there is a design, there is a Designer.
How would such a Designer communicate the reality of Himself? His intellect and creativity has created a world that reflects His goodness, His power, and the wonder of what and who He is. There are also evidences from the "inner" worlds of the human mind and heart. We have an innate sense that life continues into eternity (Ecclesiastes 3:11). Why are we always so shocked and surprised when a person dies? To naturalistic creatures, this should be an accepted thing. It happens every day. It is the end result of every person's life. There should be nothing surprising or horrifying about it—unless we are somehow certain, deep down, that there is something after, something unknown to which the dead have gone. This is what is called "numinous" fear. It is the fear of a ghost or spirit, as opposed to the fear of a wild tiger or a car crash. It is spiritual, as opposed to natural.
In every human culture, two things exist: morality and worship. A culture, or people within that culture, can be amoral, or immoral, but there is always a standard which we either adhere to or walk away from. Immorality, or wrong, has no meaning without an innate moral code, what C.S. Lewis called "the law of human nature." If someone steals your food, you protest. If you know that you have the money to buy more, and time to go to the store, and nothing better to do, you still protest. Why? Because it's wrong to steal someone's food, and nobody likes having their food stolen. This, and a hundred other examples, are evidence that morality is not something we created, it is something we discover within ourselves—an unavoidable aspect of our makeup as humans. We were created in the image of God (Genesis 1:27).
We are also prone to worship. It isn't always a deity—sometimes we worship money, sex, superheroes, political parties. The point is, we tend to look to something outside of ourselves for help when we feel helpless or afraid; we tend to look to a "higher power" who can give our lives meaning. This is another evidence that we are made by, and to commune with, God the Creator.
Christians always have trouble proving God's existence to unbelievers, and that's because we can't prove it. We can point to the evidence in nature, in morality, and in the human heart. But the strongest evidence of all is the person of Jesus Christ. Throughout the Bible there is a "voice" that the church fathers called vox Dei or "voice of God." When Jesus speaks, the Spirit of God is obviously there, in concentrated form. It is the same voice heard in nature, the same voice that speaks to us through acts of kindness, the same voice we hear when we love and are loved, the same voice that is outraged at injustice, oppression, abuse, and neglect.
The Bible tells men and women to "trust in the Lord with all your heart, and do not lean on your own understanding" (Proverbs 3:5), and it reminds all humanity that God's existence is plainly seen, because God has shown us clearly that He is real (Romans 1:19). We want proof. We want answers that we can see and feel. But God wants followers who will trust Him despite the things that we don't see, and the things that don't make sense. God is real. The Bible tells us to have faith (Hebrews 11:6) when we hear vox Dei. It commands us to be those sheep that hear the Shepherd's voice and follow Him (John 10:27; John 3:16).
Does God exist?
Is God imaginary?
Can the existence of God be proven?
Why does God require faith?
Where is God now? When life hurts and is difficult, where is God?
Truth about God