Here we see guys in goofy Lewis and Freud costumes putting forward simplistic alternative views on the origin of moral sentiments to set up a round-table discussion:
The discussion interestingly displays no evidence of these folks having read Freud's discussion of morality in Civilization and its Discontents, specifically his claim that experience in fact does not support the utility of Christian morality, but that its central tenet, "Love thy Neighbor as Thyself," is an absolute psychological impossibility, and so nonsense as a commandment.
If experience and religion do coincide in what they teach us about morality (meaning that we can give a fully adequate account of our acquisition of morality by referring to evolution and cultural forces) the younger woman (Margaret?) here says that it still helps to leave God in the explanation, because this "gives us a sense of humility." So, if we think that morality is a human creation, then, she thinks (I'm extrapolating here), we can therefore run rampant and change it according to our will, so we need to have God in there to make it objective and transcendent of any given conception we come up with of it. I do not at all agree that this is necessary, but it does point out an interesting characteristic of progressive moral thought, i.e. that there's always room for improvement not only in our specific moral rules but in our ideals themselves.
In describing the derivation of morality from human experience, we also see the naturalistic fallacy looming up again (see Wes's post on this). If you already have basic moral principles, then experience can teach us the best way to apply these, but history and science can't in themselves give us fundamental moral principles. This is not to say that these principles aren't acquired through experience (i.e. people telling us about them) or that they can't even be given in experience, as some philosophers think that moral qualities are just given in experience like sensual qualities, so I'm not arguing against humanism, but we need to keep the is/ought distinction in mind.
Lastly, right in the fake-Lewis's speech at the beginning, we see a leap from intuitionist morality to religious morality, and even before that, the host sets up the conflict as being between being given morality by culture and discovering it internally. As I've stated above, you can have a non-religious, intuitionist, self-transcending morality (like possibly Kant's, but certainly W.D. Ross's, which is much more reasonable seeming than Kant's morality anyway). You can also, as Spinoza or Mill does, give a picture of morality where society does invent morality, but does so more or less on the basis of basic human needs which (if we go along with them and don't try to deny them like an ascetic) give us a basic "innate" morality (i.e. suffering is bad). Freud adds to this picture and says that once we're inculcated by our society, we internalize this and, as faux Lewis says, we feel uncomfortable when we do wrong.
I watched a couple of minutes into video #2 of 6 making up this roundtable, and the thing is so cliché-riddled with points about Nazis and slavery and all that I can't stomach any more right now, but if anyone wants to wade in deeper and point out some particularly brilliant points that occur later on, please post about them here.