Love is all around. A romantic cliche? No, a fact of human life. Just ask Anne Marie Pahuus, a Danish philosopher at Aarhus University. Love is essentially the closest, most intense relationships we have, for instance with our partners and children. Its wide range of emotions runs from erotic passion to friendship, from delight to torment. Love can conquer all, and it can bring life-long sorrow. Down through the ages - in a variety of guises - love has been the favourite theme of thinkers and artists, as indeed it remains to this day.