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Richard Bentley is usually credited with the principle stating "the difficult is to be preferred to the easy reading." This was based strictly upon a humanistic perspective of the biblical text, that "a scribe is more likely to make a difficult construction easier, than make more difficult what was already easy."
It does not take into account the fact that the Bible is the Word of God and has been subject, therefore, to processes different from that of other literature.
Bentley was not a Bible scholar but a "classical scholar" who approached the Bible in the same manner that he approached ancient non-inspired writings, such as those of Horace.
Souter observes that "the impulse [Bentley] gave to [his textual] studies was such, that but for him there would have been no Lachmann and no Hort."
Metzger admits that Bentley depended to a large degree upon his own "instinctive feeling as to what an author must have written" (Metzger, p. 182). This is called "conjectural emendation." It describes an educated guess.
Even Metzger admits that Bentley's bent for conjectural emendation led him to make many decisions that were "rash and indefensible." Metzger states that the 24th edition of Nestle's Greek New Testament includes about 200 conjectures (p. 185).
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