5. Mathematical Problems
I should say first of all, this: that it shall be possible to establish the correctness of the solution by means of a finite number of steps based upon a finite number of hypotheses which are implied in the statement of the problem and which must always be exactly formulated.
This seems obvious, but it sets up the stage later for Turing and his answer to the halting/decision problem.
Author: David Hilbert
Original date: 1900