Lately I've been thinking about the logical problems to do with consistency and inconsistency. I don't mean "consistency" in the mathematical sense of a "self-consistent system". I mean in pragmatic terms: if you take one approach to a certain situation, but take a different approach to another similar situation, is that wrong? Does it have the status of a logical fallacy? Or something more complex?
In some cases we have a special name for inconsistency: "unfairness". That is, if in one circumstance you are unkind and in another comparable circumstance you are kind, that can be called "unfair". But does this mean you have to be a bastard just because you were a bastard in the past, lest people say notice your change and accuse you of inconsistency? To take a legal example: are the courts obliged to mindlessly repeat the patterns in precedence, for the sake of consistency (which is argued to be a specific form of "equal treatment under the law"), even when precedent is plainly unfair in other aspects?
Moreover, just the concept of consistency presumes that you can take several different circumstances and argue that they either are or aren't comparable. So: "if the news is thick with coverage of Zimbabwe's troubles, but nothing about Zambia's, is this inconsistency, possibly motivated by the fact that there's white people being stomped on in Zimbabwe but not Zambia?". Possibly -- but maybe Zimbabwe and Zambia are just different situations; or maybe not so different at all.
And moreover, in all things there is a degree of emotional motivation, which you often can't get to work consistently. I.e., just because I care about one person, doesn't mean you can get me to care about someone who you can agree is objectively comparable.
On the one hand, if I'm in glorious downtown Albuquerque and see two panhandlers, and give money to the one and not to the other, I would take a dim view of anyone who says "You're being unfair, because the first one is Navajo and the other one is Hispano" or the first a man and the second a woman, or the first clearly disabled and the second not, etc. But on the other hand, if I ran a homeless shelter whose policy (explicit or de facto) was to help only Hispanos, or only Catholics, or only English-speakers, etc., that would be clearly less defensible. But when I try to answer "why?", I feel like I'm just rationalizing, more than enumerating the clear reasons.
To take a more topical example: The Axis of Evil! The argument goes that [the governments of!] Iraq, Iran, and North Korea are Evil(tm) because they want to develop nuclear/chemical/biological weapons. The US government has nuclear/chemical/biological weapons. Does that make the US government Evil(tm)? Ah no, because Evil(tm) is something that only others can be! Okay, how about Israel's government? The Israeli military has never met a Strangelovian weapon they doesn't like; does that make them Evil(tm)? Ah, no, because Israel Is Our Friend(tm), of course.
And how about China's government? They're not exactly friendly with the US; they have nuclear, chemical, and biological weapons; they have a habit of selling arms to about the nastiest people they can find on Earth; and every now and then they conduct "missile tests" within an inch of Taiwan, showing that wise restraint is not among their skills. But they can't be in the Axis of Evil(tm) because they do things like make sunglasses and clock radio that we buy at Walgreen's.
On the one hand, the truth of the statement "Iraq's government is Evil(tm)" shouldn't have to depend on the truth of the statement "China's government is Evil(tm)". Doing something about one but not the other, is definite inconsistency, but one could argue that one has to start somewhere. And there is such a thing as wisely choosing one's battles (altho "battles" is usually used metaphorically there!).
But on the other hand, it's hard to get the masses riled up against an enemy that is basically The Axis Of Those Who Are Evil Yet Small Enough To Rattle Our Sabres At While We Ignore Clearly Greater Evils Elsewhere, Because Ah Well.
In fact, that way madness lies. And I've been there, and they don't validate parking.
This consistency problem is like pulling at a thread on a shirt and having the carpet unravel.