I've never had any sort of therapy, but I have done some personal development courses in which similar sorts of dialogue take place.
The thing is, we are all running on corrupt hardware (a phrase I couldn't find in a top-level post, which surprised me -- maybe there's scope for an article on the theme). (ETA: thanks to JGWeissman and ciphergoth for locating this article.) When asking ourselves the fundamental question of what we believe and why, we have to take that into account, and it goes way beyond the usual lists of cognitive biases. I don't see "depression" in this list, or for that matter "optimism", "mania", "self-effacement", "overconfidence", "introversion", "extraversion", or any other general patterns of mood and background belief that greatly affect how a person lives their life. How do you uproot a belief which seems convincing to you, that you can even talk the hind leg off a donkey defending with seeming evidence, but which you have just the tiniest suspicion is no more than a figment of your mental constitution? Rigour in assessing that evidence, and your evidence for believing that it's evidence, and so on, is one way. If CBT as typically practiced does not reach that level of rigour (and whose thinking does?), well, a blunt knife can be more dangerous to its user than a sharp one, but it need not be perfectly razor-sharp if it does the job.
An additional complication in the present context is that beliefs cause actions, and actions cause outcomes. If the beliefs are about those outcomes then there are problems of circularity. Contrary to (C) in the top-level post, the student's belief "I'm inadequate" has a very clear anticipated experience: failing in her course. The (rather lukewarm) replacement anticipates a chance of success. However, "I'm inadequate" is likely to cause failure to work on the course, which causes failure on the course.
Here's a very simplified payoff matrix. Assume that whether you pass a course depends solely on whether you work at it. If you work you will pass, if you don't you will fail. The payoff for passing is 1, for failing 0.
work don't work
believe you'll pass 1 0
believe you'll fail 1 0
If this is the situation, then clearly you should work, and having made that decision, believe you will pass. But if you only work if you believe you'll pass, the table becomes:
work don't work
believe you'll pass 1 n/a
believe you'll fail n/a 0
Both beliefs are then no more right or wrong than the sentence "this sentence is true". They try to reach past the means of producing an outcome to the outcome itself, which is surely a fallacy in some decision theory or other. A correct belief in the above situation is "I will pass if and only if I work". You might then still choose not to work, because there is some better use of your time, but with the correct belief, you are in a position to make that choice.
A few relevant quotes, in chronological order:
"Know thyself." (Ancient Greeks).
"Never despair; but if you do, work on in despair." (Marcus Aurelius).
"The truth shall set you free." (John 8:32).
"When I look around and think that everything's completely and utterly fucked up and hopeless, my first thought is "Am I wearing completely and utterly fucked up and hopeless-colored glasses?"" (Crap Mariner).
Re "corrupted hardware", the source article appears to be Ends Don't Justify Means (Among Humans).
"Cognitive behavioral therapy" (CBT) is a catch-all term for a variety of therapeutic practices and theories. Among other things, it aims to teach patients to modify their own beliefs. The rationale seems to be this:
(1) Affect, behavior, and cognition are interrelated such that changes in one of the three will lead to changes in the other two.
(2) Affective problems, such as depression, can thus be addressed in a roundabout fashion: modifying the beliefs from which the undesired feelings stem.
So far, so good. And how does one modify destructive beliefs? CBT offers many techniques.
Alas, included among them seems to be motivated skepticism. For example, consider a depressed college student. She and her therapist decide that one of her bad beliefs is "I'm inadequate." They want to replace that bad one with a more positive one, namely, "I'm adequate in most ways (but I'm only human, too)." Their method is to do a worksheet comparing evidence for and against the old, negative belief. Listen to their dialog:
[Therapist]: What evidence do you have that you're inadequate?
[Patient]: Well, I didn't understand a concept my economics professor presented in class today.
T: Okay, write that down on the right side, then put a big "BUT" next to it...Now, let's see if there could be another explanation for why you might not have understood the concept other than that you're inadequate.
P: Well, it was the first time she talked about it. And it wasn't in the readings.
Thus the bad belief is treated with suspicion. What's wrong with that? Well, see what they do about evidence against her inadequacy:
T: Okay, let's try the left side now. What evidence do you have from today that you are adequate at many things? I'll warn you, this can be hard if your screen is operating.
P: Well, I worked on my literature paper.
T: Good. Write that down. What else?
(pp. 179-180; ellipsis and emphasis both in the original)
When they encounter evidence for the patient's bad belief, they investigate further, looking for ways to avoid inferring that she is inadequate. However, when they find evidence against the bad belief, they just chalk it up.
This is not how one should approach evidence...assuming one wants correct beliefs.
So why does Beck advocate this approach? Here are some possible reasons.
A. If beliefs are keeping you depressed, maybe you should fight them even at the cost of a little correctness (and of the increased habituation to motivated cognition).
B. Depressed patients are already predisposed to find the downside of any given event. They don't need help doubting themselves. Therefore, therapists' encouraging them to seek alternative explanations for negative events doesn't skew their beliefs. On the contrary, it helps to bring the depressed patients' beliefs back into correspondence with reality.
C. Strictly speaking, this motivated cognition does not lead to false beliefs because beliefs of the form "I'm inadequate," along with its more helpful replacement, are not truth-apt. They can't be true or false. After all, what experiences do they induce believers to anticipate? (If this were the rationale, then what would the sense of the term "evidence" be in this context?)
What do you guys think? Is this common to other CBT authors as well? I've only read two other books in this vein (Albert Ellis and Robert A. Harper's A Guide to Rational Living and Jacqueline Persons' Cognitive Therapy in Practice: A Case Formulation Approach) and I can't recall either one explicitly doing this, but I may have missed it. I do remember that Ellis and Harper seemed to conflate instrumental and epistemic rationality.
Edit: Thanks a lot to Vaniver for the help on link formatting.