Is seeing believing?

To a larger extent, i do agree that seeing is believing because we as humans, its in our natures to not really believe someone without them showing a proof. We believe in what our eyes see and that's what we say its the truth-what our eyes see. In court cases, lawyers have to present evidence in favour of his client. 

Why does he have to present evidence? 

Because he knows that the judge can not believe anything he sees without giving justifications and evidence to his statements. It the same thing in real life situations.

However, nobody has seen God but still people believe in Him. So its not necessary for one to see something in order to believe in it. People believe in reincarnation. We don't know even know if it exists or not.

 Hence, it is not necessary to see something in order to believe in it.