A Swiss scholar, Jacob Burckhardt, wrote a book named 'The Civilization of the Renaissance in Italy', in which he wrote, "this culture was charecterised by a new belief - that man, as a individual, was capable of making his own decisions and developing his skills."

From that time onwards man, began to question the then existed believes and the age of rationalism developed. Man realised that for every thing that existed there is an explanation which can be scientifically proved. Based on this various hypotheses were put forward for the existence of God by the believers and the Scientists eventually disproved each and every one of them.

Proof is what authenticates the existence of an item. Where ever we go, we need proofs. Why do you carry your passport when you are on a tour to any foreign country ? Why do you test drive a car before purchasing ? The salesman will give you a sugar-coated description about the car. But still, we will test drive it because we need proof. We need proof to accept a tale as a fact.

Personal experience is what matters the most. Believing or not believing some thing should be left to the discretion of that individual. Even a hard core atheist like me will start believing in the existence of God if and only if I meet God in person.