We like to think of ourselves as rational animals, but perhaps it would be more accurate to describe ourselves as rationalizing animals. However reasonable a view may be, it’s possible that we have acquired it for wholly irrational reasons and are now simply rationalizing it in order to maintain our self-image as consistent, rational, and moral. It’s not just a question of rationalization, either — we appear capable of making up complete falsehoods as part of this.
Massimo Pigliucci writes in the Summer 2003 issue of Free Inquiry about studies of the human brain which reveals some interesting — and perhaps disturbing — information:
Studies of patients with split brains have allowed us to begin to understand the functions and relative roles of different parts of our thinking organ. The left hemisphere, usually referred to as the "rational" side, is actually the rationalizing one, what neurobiologists call "the left interpreter." It is in charge of holding onto one person's current paradigm and worldview, no matter what the evidence. The left brain will distort facts if they conflict with the current held viewpoint.
It may sound like your brain is hard-wired to get you to lie in defense of what you believe, but it's not the simple. Instead, it seems like the brain is hard-wired to lie to you in defense of what you believe — it's not that you're lying, because you sincerely and completely believe the defense you are creating. Those defenses are not only not true, however, but they have been constructed by your brain solely for the sake of defending what you believe and regardless of whether they are true or not. And you aren't even conscious of it.
In fact, the left brain can literally make up stories if the evidence is scarce or contradictory. A typical experiment was with a patient characterized by a complete severance of the corpus callosum (which connects the two hemispheres in normal individuals). He was shown a chicken leg to the right half of the visual field (which is controlled by the left brain) and was asked to pick a corresponding object. Logically enough, he picked a chicken head. The subject was then shown a house with snow to the left field (controlled by the right brain) and, also logically, chose a shovel.
The individual was then asked to explain why he picked a chicken head and a shovel. Notice that there was no communication between the two hemispheres, and that the only hemisphere that can respond verbally is the left one. Astonishingly, the left hemisphere made up a story to explain the facts while being ignorant of half of them: the shovel was necessary to clean the chicken excrement!
I never cease to be amazed at the sorts of things that these experiments on cognition and brain function reveal. I’m sure that the average person would not have thought the above situation to be likely, but it clearly happened: a person made a choice for entirely sensible reasons, but because their brain was unable to understand or articulate them, it made up entirely new reasons and created a fictional story around them.
It's not as though they are trying to defend an indefensible or irrational position — if their brain could understand what's happening, it would be easy to provide a defensible and rational explanation. Thus the brain isn't fabricating the given explanation because the truth is somehow irrational or unacceptable; instead, the brain is fabricating an explanation because it needs some sort of rational explanation for the sake of maintaining appearances — including one's appearance as a rational being to oneself.
Simply amazing — and all the more so because the belief being rationalized here was so obviously reasonable and appropriate in the first place. It’s bad enough that a person might rationalize bad beliefs, but apparently we rationalize good beliefs as well.
How often do you suppose this happens? How many of our beliefs, especially the very good ones, are rationalized rather than rational? Clearly the ability to articulate good, sensible, and rational reasons for some position, belief, opinion, or action is not a sufficient reason to conclude that you have been thinking or behaving rationally.
Maybe your brain is just very good at fabricating post hoc rationalizations for beliefs and behaviors which can be justified rationally, but which you hold or did for completely different reasons. Should we perhaps change our beliefs about qualifies as “rational”? If we did, might that be a rationalization as well? How would we even know?
