http://www.thecommentator.com/article/3476/prof_hawking_trip_not_cancell...
Postscript:
The Cambridge spokesman Tim Holt has changed his story: “We have now received confirmation from Professor Hawking’s office that a letter was sent on Friday to the Israeli President’s office regarding his decision not to attend the Presidential Conference, based on advice from Palestinian academics that he should respect the boycott. We had understood previously that his decision was based purely on health grounds having been advised by doctors not to fly."
Maybe Mr Holt can also confirm that - in the interests of consistency - Professor Hawking will no longer use any medicine or medical procedure developed in Israel.
Postscript #2:
The more renowned is a man and the more specialised his field, the more likely he is to pronounce ex cathedra on matters on which he is totally ignorant...
Postscript #3:
How would Stephen Hawking fare in the non-Israel Middle East?
http://www.israelnationalnews.com/News/News.aspx/167837#.UYwLoEoTTdd