“Science could be compared to a great circle. The points in its interior denote all scientific achievements. What is outside the circle represents not-yet discovered regions. Consequently, the circumference of the circle should be interpreted as a place in which what we know today meets with what is still unknown, that is, as a set of scientific questions and unsolved problems. As science progresses, the set of achievements increases and the circle expands; but, together with the area inside the circle, the number of unanswered questions and unsolved problems becomes bigger and bigger.”
