11. The application of the above sources of criticism to the sacred text demands very extensive research and much sound judgment. "Canons of criticism," as they are called are valuable in their proper sphere; but, as Westcott remarks (ubi supra), "they are intended only to guide and not to dispense with the exercise of tact and scholarship. The student will judge for himself how far they are applicable in every particular case; and no exhibition of general principles can supersede the necessity of a careful examination of the characteristics of separate witnesses, and of groups of witnesses."
We bring this subject to a close by an enumeration of the last six of the thirteen rules laid down by Westcott.
8. "The agreement of ancient MSS., or of MSS. containing an ancient text, with all the ancient versions and citations marks a certain reading."
9. "The disagreement of the most ancient authorities often marks the existence of a corruption anterior to them."
10. "The argument from internal evidence is always precarious." This canon he illustrates by several examples: "If a reading is in accordance with the general style of the writer, it may be said on the one side that this fact is in its favor, and on the other that an acute copyist probably changed the exceptional expression for the more usual one," &c.
11. "The more difficult reading is preferable to the simpler." This canon rests on the obvious ground that a copyist would be more apt to substitute an easy reading for a difficult than the reverse.
12. "The shorter reading is generally preferable to the longer." Because of all corruptions of the text, additions from parallel passages, or to meet its supposed wants, are the most common.
13. "That reading is preferable which explains the origin of the others."