an interesting read: World Philosophy Day

http://news.bbc.co.uk/2/hi/uk_news/magazine/7739493.stm

How can we explain human nature?

Human nature is one of those things that everybody talks about but no one can define precisely. Every time we fall in love, fight with our spouse, get upset about the influx of immigrants into our country, or go to church, we are, in part, behaving as a human animal with our own unique evolved nature—human nature

Source: http://www.psychologytoday.com/articles/pto-20070622-000002.xml

BUT ... can we universally explain it? Do any of the theories we;ve looked at help us? Why ? Why not?
What do you think the explanation is?