Maverick,

Research suggests that morality is not evolved to be rationally consistent. The basic idea is that we get our "moral" sense from a series of biological impulses that govern how we treat family. So, scientists have noted for a few decades that in animals, empathic, selfless, behavior tends to be reserved for those who are genetically closer to us.

Humans are an astounding species in many ways. One is that our powerful cognitive ability allows us to generalize things from one mental "class" to another, with such force and reality that we can feel the emotions and impulses associated with one "class" by proxy for a second. So, we can take that suite of kin-based empathic, moral behaviors and, through a bit of cognitive gymnastics, feel it in a very genuine way for others as long as we conceive of them as "like family."

We can do this with trees. We can do this with a patch of land. We can do this with pretty much anything we can invest with a sense of family (or, I suppose, home. Not quite sure how the patch-of-land thing ties in).

We can also, through a complicated series of mental gymnastics, take that sense of family and kin away. Historically researchers have explored this concept under the banner of "dehumanization."

Anyhow, I'd argue that the better way to think of human morality is that we are remarkably consistent, non-hypocritical, and undifferentiated in our morality for those we have mentally classified as "in."

And we are remarkably consistent, non-hypocritical, and undifferentiated in our lack of morality and empathy towards those we have mentally classified as "out."

The inconsistency is in what we classify as in or out. That's where we start seeing the most blatent forms of hypocrisy, and is most evident in those areas where cultures or political affiliations disagree on what should be classified as "in."

Dogs are one of the blurry boundaries. In western cultures we consider them "in" and therefore have a deep moral aversion to the thought of eating them for food. In other cultures they are "out" and are objects that can be treated as food.

Another one is the abortion debate. Without speculating as to the motives of both sides, much of the debate boils down to a cultural argument over when a developing fetus should be considered "in" and when they should be considered "out."

Again, this is without speculating as to the motives of either side. People on both sides of the debate have questioned the genuine-ness of the moral feelings on the opposite sides of those on the opposite sides of the political spectrum. But whatever the motives, the debate itself often was cast in terms of when we should start treating the fetus as a human, probably because no matter what other motives are at play, the psychological need to determine the "in" vs. "out" threshold is so important that it becomes a battleground anyway.

Over the last two hundred years science has upended a great many of the conventional notions of human rationality. We're not morally consistent by nature; rationality and consistency are values that we achieve after a lot of work.