The ting to remember about many intellectuals is that their learning is, as the study your FB associate mentioned, from clinical, controlled studies. Most will deisgn a study to look for an answer to a question and they will often rig the study to get their desired answer, thus making them feel smart. This is hard to do with pure sciences like mathematics, physics, etc., though it is attempted as scientists try to prove their pet theories. When it comes to the soft sciences, or more correctly philosophies, such as the social sciences, etc., it is harder to get solid data since tests can be rigged.
What can be learned in the philosophies is through straight observation. By observing the outcome of a philosophy, we can see if it works as advertized. Still, one has to correct for outside variables. For example: today some say Capitalism has failed, ignoring the political dimension that prevent Capitalism from working correctly in the first by injecting favoritism into the system and creating opportunies for criminals to take advantage.
Sacrifice is a term I have come to very much dislike. To me it has come to mean a forced taxation of one's resources to give to another who probably doesn't deserve it. This can be physical force of the threat of the taxman and prison or force through guilt that you "should" help those down on their luck regardless of why they are down or if they intend to stay there living on handouts. I can see helping family if they are really in a rough patch and are intending to get back on their feet, friends too maybe. I don't think it is wrong with such help to give it conditionally and expect them to make good use of it. If they don't, then, well, they don't get anymore, hard as that might be to do.
Giving a gift is different. Giving a gift is something you want to do without expectation of return. This is done because you want to not because you "have to." This makes you feel good because it is done because of your feelings for the person receiving the gift. You could say you still profit from this exchange because you feel good by making them feel good at getting a gift, but that's fine too.
Anyway, here is what Ayn Rand says about sacrifice and I suppose this is how I have always felt about it, just put in clearer terms.
http://aynrandlexicon.com/lexicon/sacrifice.html