Saul Kripke is widely and justly admired for his brilliant technical work in symbolic logic; but his most influential contributions have been to two ancient and related problems concerning meaning and necessity.
The problem about meaning is simple. People make noises with their mouths and marks with their hands. What is the difference between those that are just noises and marks and those that manage to say things, perhaps about distant times and places? How, for instance, does “Napoleon was banished to Elba in 1814” convey, to us now, something about a nineteenth-century Corsican despot?