we lie with our clothes the same way we lie with our words. whether we're trying to conceal wisdom, confidence, wealth, strength, compatibility, etc... there's a distribution to the potential gain and chance of getting "called out". That's assuming we're making a concious choice. A big portion of it is effective marketing making us insecure about all those things we try to conceal first, whether we are missing in any of those deparments or not. I think it's much more subconsious that we'd like to admit, particulalry if we think we're so rational.

Even if man really were nothing but a piano-key, even if this were proved to him by natural science and mathematics, even then he would not become reasonable, but would purposely do something perverse out of simple ingratitude, simply to gain his point.

—Fyodor Dostoyevsky, Notes from the Underground

(Self-promotion: this is the epigraph to the novella I'm working on, which is not really about rationality but is about what we're pleased to call "human nature", and which you may read the beginning of here if so inclined.)

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. 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 continues in the Summer 2003 issue of Free Inquiry:

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 story around them.

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 rational<i>ized rather than rational?

Should be perhaps change our beliefs about qualifies as “rational”? If we did, wouldn’t that be a rationalization as well?

It may just be semantics and a look into the biological process of decision making. I think there've been studies to show that our body tends to react to the question of which card deck is better 2-3 times before our rational self declares so. It may just be the process of a body forming a "hypothesis" and then subjecting it to a scientific type test before creating and declaring a rational theory.

What is everyone's response to - "people aren't rational, they're rationalizers"? I'm very new to the blog, but figured this would be the perfect place to get some thoughts on this idea.