There is no cause to doubt that Christ lived.
Because you did not see him and feel him yourself as Thomas did, why should you doubt his existence?
If you can doubt that, you may as well doubt that your great grandfather ever lived; because you never saw him nor touched him. Logically, there is fair assumption for you to believe that your grandfather whom you knew must have had a father in order to have been born. Logically, his father must have been your great grandfather.
You don't have to see everything to believe it. You must trust some things to those who lived before you.
You have good reason to believe that somebody or something existed before you came here.
Never doubt that Christ lived; never doubt that God lived because great things happened to prove that before you came into the world.
Deny that positively which you know of, and not that which you do not know of”.