The identification of transmission errors may help determine the relationship of one manuscript to another or, even more importantly, determine the textual variant which most likely represents the reading of the original manuscript. It may be said that a discussion of the transmission errors is not a criticism against the trustworthiness of the documents. Finegan, Encountering the New Testament Manuscripts , p. 55. Unintentional Variants Scribal errors create variants in the textual tradition. One type is referred to as unintentional variants and have several causes.
Some errors seem to have been caused by a visual difficulty during the copy process.
During the process of reading from the exemplar and beginning to write it on the copy, a scribe could make mistakes as he repeats the line. These are some of the main causes of variants that can be described as intentional.