In Einstein's day, there were only a few thousand physicists worldwide, and the theoreticians who could intellectually rival Einstein probably would fit into a streetcar with seats to spare.

在爱因斯坦的时代，全世界只有几千名物理学家，那些在智力上能与爱因斯坦匹敌的理论家，可能一辆有轨电车就都坐下了。