Jonathan Ellis and Eric Schwitzgebel in Imperfect Cognitions:
We’ve all been there. You’re arguing with someone – about politics, or a policy at work, or about whose turn it is to do the dishes – and they keep finding all kinds of self-serving justifications for their view. When one of their arguments is defeated, rather than rethinking their position they just leap to another argument, then maybe another. They’re rationalizing –coming up with convenient defenses for what they want to believe, rather than responding even-handedly to the points you're making. You try to point it out, but they deny it, and dig in more.
More formally, in recent work we have defined rationalization as what occurs when a person favors a particular view as a result of some factor (such as self-interest) that is of little justificatory epistemic relevance, and then engages in a biased search for and evaluation of justifications that would seem to support that favored view.
You, of course, never rationalize in this way! Or, rather, it doesn’t usually feel like you do. Stepping back, you’ll probably admit you do it sometimes. But maybe less than average? After all, you’re a philosopher, a psychologist, an expert in reasoning – or at least someone who reads blog posts about philosophy, psychology, and reasoning. You're especially committed to the promotion of critical thinking and fair-minded reasoning. You know about all sorts of common fallacies, and especially rationalization, and are on guard for them in your own thinking. Don't these facts about you make you less susceptible to rationalization than people with less academic intelligence, vigilance, and expertise?
We argue that no. You’re probably just as susceptible to post-hoc rationalization, maybe even more, than the rest of the population, though the ways it manifests in your reasoning may be different.