On the other hand, it would seem that many of the top experts today are masters at mashing up the frontiers of multiple fields. Just think of all of the applications of Neuroscience + X (CS, Philosophy, Psychology, Chemistry, etc.). Sure, there are few (no?) people today that can claim mastery of 10 or 20 fields, but most of the cutting edge research does seem to require expert knowledge of 2 or 3.