We have a big yard and there's woods all around us, and I'm going to look under the trees, so if I find them I'm going to get some toothpicks and open it."

VOA: special.2011.07.11

The reason it looks like a tautology, because you look around, nothing seems to have its velocity forever.

其原因听起来像是绕圈子,因为你看看四周,似乎一切都不可能永远运动下去

耶鲁公开课 - 基础物理课程节选