How do you control for your bias?
This seems like an open question, and I'm not particularly sure what you're asking about specifically.
So, you know precisely what is happening in your brain?
I'm confused. Are you saying that I do not really know why I ate the cheesecake? That may be so... and in fact, it's probably likely. But that's beside the point.
I know I ate the cheesecake. I know what problem I have to solve--why I ate the cheesecake. And I know I did it because I had a desire, though perchance I'm using terms a bit differently than you.
Maybe you're inferring that I think I know what happened in my brain because I mentioned "I was there when I rationalized...", but that would have been taken the wrong way. I don't know why I do every little thing, but there are indeed situations where I do in fact catch myself rationalizing, and in those situations, I don't have severe reasons to doubt that I rationalized it. The reason I mentioned this is because it tends to be a stereotypical thing to happen on a diet (the "I'll only eat one"/"I'll exercise more" notion), not because I'm trying to suggest we are constantly aware of these things.
Heh... okay, I won't ask you to define conscious here... but yeah, I'm perfectly aware that most of the time I'm stuck in a sort of "autopilot"... it's quite intriguing.
Have you ever had a sore on your tounge and you kept scraping it against your tooth? You could consciously keep yourself from doing it but eventually you would lose focus and the tounge would be scraping agaisnt the tooth again even though you didn't want it to. Why?
More specifically, you wanted to not do it (the modal correction here for emphasis that this is a goal--perfectly okay to speak this way loosely otherwise given you're aware of it). But you also had a desire to do it. This is, in fact, quite what you're describing--you're suppressing a
desire to perform this action you do not want to do.
Maybe I'm being more inclusive with the term "desire" than you. I view desires as internal states--manifest when you have little goals you want to achieve, which if you're lucky, you're aware of. In addition, these little goals are about things that require some sort of perception, analysis, etc in order to achieve (by virtue of being worthy of being called "desire"), and are abstract things--the goal is not exactly the same thing as obtaining it (eating an orange works just as well as the cheesecake, but going for that celery stick does nothing), and may or may not be even be something that can be "achieved" (that is, goes away once it is reached). You don't necessarily know what these things are, but you have them, and those are the things that interfere with your higher level goals, in the specific scenario I imagine that we're talking about--where you have "weakness of character". I've yet to discuss the other sort of "lack of power", but I think it's a bit more obvious (I cannot break my track record--I can mitigate this by a different sort of approach--by training more).
Recently I've been studying OCD, someone I care about has it, and it amazes me how seeminly simple it should be to overcome this specific affliction. Why is it so hard? Something inside me wants to scream "stop it"!
I might just be fooling myself, but I find with a bit of creativity, I can map something onto quite a number of alien situations in order to at least get a picture of what it's like. With respect to OCD, holding my breath for a while seems to do the picture--I can easily imagine having a "little goal" to accomplish certain sorts of things, similar to that urge to breath, that I quite simply cannot overcome.
My conclusions are simply that I don't think we are as in control of our behavior as we would like to think we are.
Wouldn't that depend on how in control you think you are?

All I'm talking about is the things that could possibly count as will. They happen for reasons. Going back to the topic of hand, we're considering LFW, and your failed diet. I'm pointing out that even in your failed diet, there's a reason you failed. And yet, oddly enough, there may be ways you can succeed, but it's best met by trying to work with yourself rather than plow over your "little goals". This is done by using strategies. These are the sorts of things we can will to do with complex acts, such as dieting. But through it all, nothing here looks even remotely indeterministic--if it were, we certainly cannot say that we were the cause in any sense.
Like the ego I suspect it is largely an illusion.
I suspect it's a bit fuzzier than that. Probably the biggest fuzzy thing is where you draw the line around the self. That sort of matters with respect to whether or not you call it will, but since I'm only trying to speak to what can be called will, I'm sort of ignoring this piece.