In the same way, therefore, one would expect that the speed of light would appear to differ according to its direction relative to the motion of the Earth through the aether.

• 这个一直以来是被当作无需证明的公理使用的。同样的，所以有人会猜想光的速度会根据地球在宇宙中的相对运动方向而呈现出不同。