samwik: "Yes, but manners have to be taught."

To a degree, yes, but I think that they are 'learned' as much as 'taught', in the same way that a child learns its mother tongue.

samwik: "if you don't have an institution to pass these on, they seem to fade away within a couple of generations...I don't think the "institutional" answer (religion) is the best way to go; but without it, what else is left?"

We do have other institutions (and in my opinion far more important ones), the most important being the home and family, followed closely by school. Society as a whole, however, determines what is "mannerly". Conformity is promoted and enforced, as mentioned, within the home and educational institutions; but society, in general, encourages the maintenance and perpetuation of good manners by social-pressure. People are rewarded and punished for their behaviour from day to day. For example, successful interpersonal relationships, and often one's livelihood, depend upon one's ability to comply with a socially acceptable code of mannerly conduct. This is part of the matrix of social structure, in which religion may or may not play a significant role. If religious institutions were to vanish altogether from English culture, I wouldn't be concerned about the future of good manners.

Terry, I just saw your post.

I agree, except that I think it's important to differentiate between manners and ethics, which overlap but are not the same.

To recap on what we already know: "manners" includes rituals that have no intrinsic ethical value, and the rituals can differ between cultures. They often signal recognition of status, rather in the way that a dog will lower its head to acknowledge the dominance of another dog. Among humans the system can be quite complex and good knowledge of the local social “pecking order” is sometimes a distinct social advantage.
"Time is what prevents everything from happening at once" - John Wheeler