Thought and science are therefore raising problems which their terms of study can never answer, many of which are doubtless problems only for thought. The trisection of an angle is similarly an insoluble problem only for compass and straight-edge construction, and Achilles cannot overtake the tortoise so long as their progress is considered piecemeal, endlessly having the distance between them. However, as it is not Achilles but the method of measurement which fails to catch up with the tortoise, so it is not man but his method of thought which fails to find fulfillment in experience.