‘Rational’ is the positive term used to command beliefs, actions, processes as appropriate. In the case of beliefs this means likely to be true, or at least likely to be true from within the subject’s perspective. Thus, rationalization is the process of interpreting an agent’s actions and sayings in order to see them as rational. To accept something as rational is to accept it as making sense, as appropriate, or required, or in accordance with some acknowledge goal such as aiming at truth or aiming at the good.
Supposing Tony decides to do something really nice for his brother on his birthday and buys him a particular brand of a new car. And Tony tells his brother “you’re going to be glad you have this car, because it is exclusive and luxurious.” Tony is confusing his brother desires with his own. When we use a false pretext to satisfy our own desires or interests, we’re guilty of rationalizing. Rationalizing involves a confusion in thinking, and to the extent we wish to avoid being confused in our thinking, we should try to avoid rationalizing.
But one may argue, it is good to do nice things for other people. If you do something that helps them, or that they like, or that benefits the world, what difference does rationalization make? If for whatever reason, the new car makes Tony’ brother happy, that’s what counts. But whether Tony’s brother is happy or not, there has been a confusion in his thinking. And it is a common fallacy indeed. Obviously, most instances of rationalizing are not a blatant as Tony’s, but people frequently deceive themselves as to their true motives.
Rationalizing need not be selfish either. Let’s say an artist or comedian is elected President of a country with robust entertainment industry, he/she decides to leverage on the entertainment potentials and activities. He/she may think such decision is in the interests of the country -when in fact he/she is motivated by self-desires to promote the country entertainment industry to the extent that he/she is deceiving him/herself about his true motivation. This is rationalization! But this may not be a selfish rationalizing; his/her actions may not benefits him/her personally.
Rationalizing involves an element of self-deception, but otherwise it isn’t necessarily devious. However, some people encourage others to rationalize because they themselves stand to benefit in some way. For instance, if Tony’s friend say to him, “hey, guy, that’s a fine idea! Really cool. Your brother will really like that brand of a new car. Maybe I could cruise with him sometimes”. Tony’s friend may or may not so this innocently. If he does, he too is is guilty of rationalizing; if he doesn’t, he’s just cynical.