This one comes courtesy of Derek Ashton:
The goal of textual criticism is to painstakingly work back toward an inerrant original, to discover its actual contents as best we can.
Inerrant original? Where’d that ‘inerrant’ come from? Let’s see how some textual critics define it, shall we?
Textual criticism deals with the origin and nature of all forms of a text, in our case the biblical text. This involves a discussion of its putative original form(s) and an analysis of the various representatives of the changing biblical text. The analysis includes a discussion of the relation between these texts, and attempts are made to describe the external conditions of the copying and the procedure of textual transmission. Scholars involved in textual criticism not only collect data on differences between the textual witnesses, but they also try to evaluate them. Textual criticism deals only with data deriving from the textual transmission—in other words, readings included in textual witnesses which have been created at an earlier stage, that of the literary growth of the biblical books, are not subjected to textual evaluation (see chapter 7). One of the practical results of textual analysis is that it creates tools for exegesis. (Textual Criticism of the Hebrew Bible, 2nd rev. ed., 1-2)
Paul D. Wegner:
Briefly stated, textual criticism is the science and art that seeks to determine the most reliable wording of a text. (A Student’s Guide to Textual Criticism of the Bible, 24)
Bart D. Ehrman:
At Moody, I learned the basics of the field known as textual criticism—a technical term for the science of restoring the “original” words of a text from manuscripts that have altered them. […] The more I studied Greek, the more I became interested in the manuscripts that preserve the New Testament for us, and in the science of textual criticism, which can supposedly help us reconstruct what the original words of the New Testament were. (Misquoting Jesus, 5, 7)
The textual critic seeks to ascertain from the divergent copies which form of the text should be regarded as most nearly conforming to the original. […] The science of textual criticism deals with (a) the making and transmission of ancient manuscripts, (b) the description of the most important witnesses to the New Testament text, and (c) the history of the textual criticism of the New Testament as reflected in the succession of printed editions of the Greek Testament. The art of textual criticism refers to the application of reasoned considerations in choosing among variant readings. (The Text of the New Testament, 2nd ed., v-vi)
Because two copies of a text will have wording in common between them, in practice a variant reading describes the places where the common text ceases, and each has its own form. ‘Variant reading’ is in fact a simple tool for breaking down the differences between two or more copies into manageable units. […] Textual criticism is the analysis of variant readings in order to determine in what sequence they arose. (An Introduction to the New Testament Manuscripts and Their Texts, 4, 159)
No need to belabor the point, which again, is simply the fact that textual criticism has no concerns about inerrant originals.