We tend to refer to him as doubting Thomas but if in fact all he did was doubt that could have been a virtue. Doubt can be the impetus for life-long learning.
The question that constantly seeks an answer.
Fides quaerens intellectum.
Faith seeking understanding, the motto of St. Anselm.
To understand the real problem with Thomas we need to stop and think about how we distinguish what we know from what we believe, statements of fact and statements of faith.
The word fact comes from the word to do or to make in Latin. Thomas wants facts. He wants to see with his own eyes, touch with his own hands.
Statements of faith on the other hand are things we accept as true because we trust the source from which we received them: a teacher, a book, a website. In reality most of what we think we know, we actually believe.
I believe the planet mercury exists and is closest to the sun.
I have not seen it with my own eyes.
I believe Thomas Jefferson wrote the Declaration of Independence.
I was not there and did not see it happen.
Imagine how ignorant we would be if we refused to accept as true any piece of information we had not personally verified.
Thomas' vice was not doubt but distrust, distrust which reflects a deeper egocentrism.
If I declare myself to be the only one fit to judge what is true, how arrogant am I? If I trust no one but myself, how egocentric have I become?
The word disciple means student, and education at its heart is a trust exercise. We trust the book. We trust the teachers. Or we make ourselves the sole judge of truth, and remain in our ignorance.
Thankfully Jesus forgave Thomas, and today we call him St. Thomas.
But remember we are told more importantly. Blessed are they who have not seen, but believe.
Blessed are we when we are willing to trust that there are others who know more, and learn from them.