To solve a problem or to reach a goal, you don't need to know all the answers in advance. But you must have a clear idea of the problem or the goal you want to reach.
Bio: Elijah ben Solomon Zalman, known as the Vilna Gaon or Elijah of Vilna, or by his Hebrew acronym HaGra or Elijah Ben Solomon,, was a Talmudist, halakhist, kabbalist, and the foremost leader of mitnagdic Jewry of the past few centuries.