Consider the following facts.
1) Any learning process starts from ignorance. For instance, when a human begins learning to play violin, he only produces bad sounds. From the first bad sounds he can go toward virtuosity.
2) When a new word is read, frequently one assigns a bad meaning to it. After reading the same word in different contexts, the proper meaning can be deduced.
3) For our ancestors Earth was plain. Now is almost a sphere.
4) Each truth is the limit of a sequence of corrected errors.
5) Even preserving the same books, dogmatic thought changes as time runs.