How much are we paying for this war? Ian Dennis Longstaff writes: Re. "Critical thinking the first casualty of war" (Tuesday). The last armed mission over Iraq presumably carried guided bombs. Were these jettisoned over the sea prior to landing for safety reasons? This would be the norm. How much do these guided bombs cost? What were the other costs of the mission with long-range flight refueling, etc? We have recently seen on TV one used to destroy a truck -- perhaps worth $5000! The "war"cannot be won from the air. Air just provides cover for ground troops, and there are none. Do you trust the Yanks with your fingerprints? Warwick Hempel writes: Re. "You can trust us with your fingerprints and retina scans, says Immigration" (yesterday). If you have ever been unlucky enough to go through the US immigration “service” you will already have had your fingerprints and retina scan added to their database. On a trip to Canada our plane landed in Hawaii to refuel. It was 12.30 at night and the plane was only on the tarmac for one hour. We were all taken off the plane and put through United States immigration procedures, which included fingerprinting and close facial photographing and then put straight back on the plane without ever leaving the airport secure area. US Immigration officials were a charming bunch of people with personalities that even a rottweiler would be ashamed to display. On science v faith Keith Binns writes: Re. "Razer and Ben Affleck take on the atheists" (yesterday). I know I'll get howled down as I'm attacking a cherished atheist myth, but Helen Razer's claim that "it is absolutely true that science and reason could only take hold in an era that had begun to fell god as an organising principle" is highly debateableAnd after you've howled me down you might care to actually investigate the issue by reading David Bentley Hart's Atheist Delusions, Yale University Press.