One, two, three. four...

Is a conductor (orchestral) really necessary?  The question arises because an orchestral concert in Pisa, Italy was conducted entirely by a robot.  Or was it?  The robot "learned" its movements by following the movements of the orchestra's resident conductor, so just who was conducting?  Really all the robot was doing was following a program - a set series of instructions - and there's nothing remarkable about that.  The more interesting question, which well predates computers and robots, is does an orchestra really need a conductor at all?  After all, these are professional players who have rehearsed together and know the piece they are playing - does someone waving a stick at them really make any difference?  Smaller groups, like string quartets and such, manage without a conductor.  So why not full orchestras?  I don't know the answer, but to my mind, a conductor - and who it is - certainly does make a difference, although I'm not sure why.