Larry says we have to believe. We should believe enough to follow Christ and do what Christ wants us to do, including living out our faith, being honest, and generous, and sharing what God has done for us.
Many say seeing is believing, that they will believe what they can see and understand. I think of Larry and a couple of others who would argue.
Saint Augustine went further. He said, from Hebrews 11, that faith is to believe what you do not see; the reward of this faith is to see what you believe.I think they are right. When I believe, and live out that belief, I am getting the vision of what God wants my life, others, and the earth to be. As I see God's vision, I begin to see what I believe, about God, myself, and the world. Believe and you will see!