post-mortem

Now, a few words on looking for things. When you go looking for something specific, your chances of finding it are very bad. Because, of all the things in the world, you're only looking for one of them. When you go looking for anything at all, your chances of finding it are very good. Because, of all the things in the world, you're sure to find some of them.

Almost a century ago, Werner Heisenberg formulated one of the great principles of quantum physics, which describes the behavior of particles at atomic and smaller scales: one can accurately determine the position of a particle OR one can accurately determine its motion, but one cannot determine both accurately at the same time.

Reference: http://www.porcupine.org/forensics/forensic-discovery/chapter1.html