I think the question is not "Is it possible to know too much?", but rather "Is it possible for too much information to overwhelm our ability to know anything at all?". In which case the answer is a resounding yes! The delta between what security professionals can collect today and what they can process is called the "Security Gap" and it's getting bigger every day.
"The answer in both America and Britain has been to collect more haystacks: useless, indiscriminately acquired information on people who've done nothing to arouse suspicion," he writes. "We even inveigle our citizens to become amateur curtain-twitchers and pecksniffs, demanding that they report "suspicious" activity to the authorities. Between DNA databases, mandatory fingerprinting for visa seekers, CCTV carpet-bombing, and Oyster card data, we've never collected more "security" information than we do today. But does this really make us secure? Is it possible to know too much?"
But, I'm not sure it's time to hoist the white flag just yet, however. A few years ago, after the bombing in London, closing the Security Gap meant assigning over one thousand MI-5 agents to manually review surveillance video. The process took over 6 weeks. Today, using new search and video analysis technology, just a handful of those agents could have probably completed much of the same work in a few days. Search technology in particular is rapidly closing the gap between the data we can collect and store and what we can "know". It's not unlike what happened with the Internet when tools like Google have made sifting through billions of images and pages as simple as typing a few key words. Suddenly this huge heap of information that had been sitting there unused by most became hugely useful when we could quickly and easily sift through it.
The prospect of these same advances in video search being applied to security is likely to greatly tame America and Britain's current jumble of haystacks, but such technology will of course bring with it a new set of problems. For those who have spent years working to close the Security Gap, I am reminded of another question about a dog chasing a firetruck.
"What's he going to do if he catches it?"