As my learned friend Ms Miller has suggested, we use the term 'ivory tower' to refer to the enclosed world of academia. The image of scientists and academics 'living in ivory towers' suggests they are out of touch with the real world and know nothing about lives and problems of ordinary people.

Others will answer more fully, but I just want to say that most of friends here in Cambridge (who are academics) happily live in ivory towers. In fact, I think of the colleges of Cambridge as one big ivory tower. My friends live in secure ethereal bliss, unaware that there is an outside world. They read about it in The Times, but they have little experience of the real world. Bless them! Ah!