Denis, your story strikes a Romanian chord. The situation around here is even worse, from what I can tell. But it is quite a fascinating question, with different answers from different points of view.
For an economist, it is a matter of price formation. In the state system, Romanian doctors are paid a fixed (and miserable) wage, largely unrelated to quality or effort. The incentive to pocket bribes is huge, and patients know it so well. In the private sector (with transparent and varied prices for medical services), bribes are almost unheard of. Also, there is a more or less efficient market for bribes. Patients find out how much a doctor expects, usually from past patients, or from other doctors. Surgeons receive more than GPs, professors more than debutants, etc.
But I think there is something more about "medical envelopes", from a cognitive point of view. First of all, there is a vast asymmetry of competence between doctors and patients, which gives the former a large freedom of action. Is this pill better, or another one? Surgery or not? Home treatment or hospitalisation? To make things worse, the post-hoc reckoning is not very helpful, since most decisions may be medically justified, but you might also end up dead. The patient is at the mercy of the practitioner since she does not know what choices are better. The best way to make sure one gets the proper treatment is to insure the benevolence of the doctor, and a bribe is the simplest path to gain the doctor's amity.
Second, there is something special about this particular social exchange: the patient is dealing in an ultimate value - her health. Something everyone in Romania says is that there is no price too high to be healthy. (Paradoxically, giving up smoking somehow does not make the list - self-hint-hint-nudge-nudge). If people would risk not bribing a policeman to avoid a fine, they are extremely unlikely to jeopardise their health in this manner. One cannot afford to stick to abstract principles (like discouraging corruption) when her life is at stake.
Finally, there is something like a Maussian gift in the affair: one passes a fat envelope even without the explicit mention of an economic exchange. It is not that the surgeon would not operate without being bribed - the patient just shows gratitude without visible economic reckoning. Of course, under the veil of generosity stands the solid self-interest of the patient. The fat envelope is meant to make sure that no scalpel is lost in her belly. But no-one says it out loud. It's a "I know that you know that I know etc" which makes sure that the transaction is smooth and polite.
To end with a personal anecdote: I was (and to some extent I still am) very wary of giving out envelopes to doctors. A little bit of moral prudishness, a little bit of fear (what if he feels insulted?), a bit of monetary unsaviness. Those who are more competent in these matters reassured me: "just put the envelope on his desk - he knows what to do next" After all, he is the expert, and I am not.


I don\'t think the purpose of apologetics is to shore up a group per se. Their purpose is to reassure the individual believer (religious, or otherwise) who is having doubts. This happens whenever someone is taught to believe things without good reasons to do so; as soon as they start to think about it, doubts creep in. And for the individual this is painful, so apologetics are very welcome.
The group, I think, is the irreducible fact in this situation - for historical reasons, there\'s a group, and you\'re in it. Apologetics makes being in that group more comfortable for you as a member, but the group is not really in danger of breaking up just because people have doubts about it.
Nations are a good example here: everyone has a nation and most people believe that their nation is fundamentally a Good one. What if your nation has done thing ostensibly wrong in the past, or still is? - well, it\'s nice if you can find rationalizations to make it seem OK. But realistically no-one is going to change their national identity even if their nation [i]does[/i] do bad things. The rationalizations are nice, maybe they help people sleep more easily, but group identity doesn\'t depend on them.
This is obvious in the case of nations, it\'s less obvious in the case of religions, because in theory a religion is a matter of \"belief\" i.e. something you could be argued out of. In theory, belief is prior to group identity in the case of religions. But realistically, it\'s not, is it? People very rarely change their religion. It\'s very nearly as much a matter of birth as nationality.
That is not to say that in certain rare cases - and perhaps at certain crisis points in an individual\'s life - one may have one\'s worldview turned upside down by a particular argument or other kind of encounter: a Road to Damascus moment. But I suspect that in those cases it is the emotional content (and context) of the experience that really counts, rather than the rational structure of the argument. It reminds me of Lakoff and Johnson\'s work on political metaphor. Lakoff would argue that liberals spend too much time constructing \"rational\" arguments, rather than simply appealing to positive emotional constructs (like patriotism, or respect for authority) as conservatives do. These positive metaphors, which offer a kind of emotional security, may be what initially attract agnostics and floating voters - and even the odd apostate - as well as obviously strengthening the commitment of existing believers.
Anyway the marketplace of religious ideas is certainly a fascinating research area and it would be great to do an ethnographic study of (say) small evangelical groups from a cultural evolutionary point of view - if one could somehow get access! Simon Coleman\'s work on Swedish evangelicals is really fascinating: he found that members of these groups would adopt a completely different and much more open kind of discourse towards him, assuming he was an \"insider\" (i.e. a fellow evangelical in general, rather than a member of their own particular church), from the discourse that they adopted with \"outsiders\" (agnostics, atheists, and even non-evangelical Christians).
Coleman, S. (2004). The charismatic gift. [i]Journal of the Royal Anthropological Institute (n.s.),[/i] 10, 421-442.