I've experienced (well, also currently experiencing) a related fear of a specific part of rationality. I've seen some people on LW and many more on OvercomingBias express beliefs that the conscious mind, the part I can call me, is so out of control that all it's good for is making up stories, rationalizing the actions of an unconscious mind guided by outdated programming and environmental factors.

Mostly, I think, I reject this idea because it would essentially mean declaring everything I've done, every decision I've ever made, and every decision I will make, as a lie. Not even one of those justifiable lies that people like to talk about in the face of radical honesty either. A huge, undefendable lie about every intention "I've" ever had. So essentially, by accepting such a belief, I've retroactively lied to everyone I know, myself included. All reasons for my actions can be thrown out the window, because none of them will ever be the actual reason unless I throw the burden of responsibility onto what is in essence a runaway mental train.

Every time someone asks me "Why do you think this is the best idea," I'll have to respond, "I don't know, but it's probably something horrifically self-serving. The driver does what they want, and I'm just here for the ride and to be the scapegoat when the idiot at the wheel does something wrong."