Jesus appeared to the apostles in person and showed them His wounds from the cross. Even with the best proof of all standing right in front of them, the apostles still had a hard time believing that He was really there body and soul and risen from the dead. If most of the apostles had a hard time believing in the resurrection with Jesus standing right in front of them, imagine how the apostle Thomas felt who wasn’t there and heard about the resurrection through word of mouth. If Thomas, had his faith in Jesus’ resurrection shaken, imagine how hard it is for us to believe 2,000 years after it happened.
In addition to scripture, the Catholic Church helps keep the memory and faith alive by passing down Sacred Traditions from generation to generation. An example of a Sacred Tradition that is not in the Bible, is that Mary was a virgin throughout her entire life. A lot of information was written in the Bible, but much what happened was not written. Some knowledge was known at the time by the people who were there and the only reason we know it today is because that knowledge was continually passed down through the generations.
Ultimately, there is no irrefutable evidence about anything related to God. We are going to have to take a leap of faith and allow our soul to think along side of our brain. If there were definitive proof in God, then faith would not be needed and no grace would be given for believing in Him. If God made Himself visible all the time, then we would lose a lot of our free will to choose Him.
I know my soul is on fire thinking and talking about God. My soul is happy and peaceful praying in front of Him in Eucharistic adoration. When I believe in God, life isn’t meaningless. I have something to look forward to when I die. Very few of us have had the privilege of seeing Jesus, but we all have the power to believe.