One of her flaws--and she had a few dillies--was her inability to admit that any part of her personality and intellectual makeup did not have a solid rational basis.

While some people are certainly more rational than others, nobody is batting 1000 in this area.

Mostly it was just silly, like coming up with complex explanations for why she liked Mickey Spillane novels. Hell, why can't you just like Mickey Spillane novels because they're entertaining, and, come to that, keep you from having to frigging THINK for an hour or so?

But other things were more serious, like her affair. I'm sure she convinced herself it was 100 percent rational, but I suspect "younger and hotter guy" might have had something to do with it (the affair blew up when Branden also went for something "younger and hotter.")

Rationality should normally be in control of emotions in a healthy person, particuarly with the important things in life. But there are so many minor things in life where one can say, "I don't have a good reason for liking pistachio ice cream, but I like it," and let it go at that. It's harmless, unless you start making decisions like who to marry, who to vote for, or what steel alloy to use in a building on frivolous impulse.

If you are the sort of person who convinces themselves that they can't have any part of their existence, even the most trivial one, that doesn't have an unbreakable logical structure underpinning it, then it's just a short mental trip to the belief that ANYTHING you think must be objectively rational and inarguable. This, I suspect, was one reason the formal Objectivist movement was drifting into the "cult" zone, and people like David Kelley and others moved out and kept the ideas fertile and changing.